In Memoriam Alison Weisskopf (1960-2018)

Alison and Oryza nivara in
Orissa, Sept. 2010

Alison Weisskopf (1960-2018), passed away peacefully in hospice in the presence of her immediate family on 11 January 2018. She was a beloved colleagues at the Institute of Archaeology, a fixture in the archaeobotany laboratory for many years and a leading figure in archaeological phytolith research, respected globally. Her research legacy is substantial as her work takes a distinctively ecological assemblage approach to reconstructing rice cultivation ecology as well as crop processing. This has proved innovative and has proved fruitful, and can be expected to continue to inspire further research and agricultural ecology approaches to phytoliths around the world. Despite first being diagnosed with late stage cancer in 2010, she soldiered on was at her most productive as a researcher over the past half dozen years, which is readily evident from her publications list. 

Bangladesh, Nov. 2013: ethnobotany

She has made lasting empirical contributions on archaeological research in China, Southeast Asia (Vietnam, Thailand, Cambodia), and South Asia (Bangladesh, Sri Lanka, India). Through ethnobotanical fieldwork (in India, Thailand, Laos) and archaeological projects (in China, Bangladesh, Fiji), many further collaborations she was a key colleague in many international networks and she leaves behind many friends around the world.

Alison joined UCL as a BSc Archaeology student in 2000/01, essentially a career reboot as a mid-life adult. She demonstrated a strong affinity for environmental archaeology and archaeobotany from the beginnings of her studies. She took my “Plants and Archaeology” in 2001/02, and a new course on “Origins of Agriculture” the following year. Her BSc dissertation on phytoliths (“A study of the phytoliths from the late Bronze Age site of Krasnoe Smarskoe, Samara Valley, Russia, and the information they provide on agro pastoral economies and environments”) supervised by Dr. Arlene Rosen was passed with distinction in 2003. In receipt of a AHRC scholarship, she continued her studies in the MSc Palaeoecology of Human societies, with a dissertation on “An investigation of the Neolithic ash mound and settlement at Sanganakallu in the south Deccan, India, using phytoliths and macro-archaeobotanical material”, combined analyses of plant macro-remains and phytoliths and received a distinction in 2005.

Liu River, near Huizui, Henan, China, 2006

She began her PhD in 2005, again funded through an AHRC studentship. She submitted her PhD thesis, Vegetation, agriculture and social change in Neolithic north central China, a phytolith study, in 2009 and was awarded her doctorate in 2010. Her doctoral research took her on field to China several times, such as to the sites of Huizui and Xipo, where she worked alongside colleagues including Arlene Rosen (now University of Texas at Austin), Gyoung-Ah Lee (University of Oregon) and Liu Li (Stanford University). Her PhD represents years of dedicated laboratory work. She later published a revised version of her PhD as a monograph in 2014.

Sept 2010: Sampling Oryza rufipogin in Orissa, with
Rabi Mohanty and Mukund Kajale

In 2009 she took up a post-doctoral research associate position funded as part of a NERC project  'The Identification of Rice in Prehistory' (2009-2012), which came to be dubbed the Early Rice Project, and spawned follow on research projects, including 'The Impact of Evolving of Rice Systems from China to Southeast Asia' (2013-2016), and 'The impact of intensification and de-intensification of Asian rice production: transitions between wet and dry ecologies' (2016-2019). During a intermission between the first and second NERC projects she secured funding through a British Academy small grant to explore comparisons between phytoliths and diatoms in rice paddy soils, and she received a travel grant from the Thai Ambassador to the UK for ethnobotanical fieldwork on non-rice plant use in Thailand. Her research, and her development of phytolith approaches to rice cultivation ecology was central to these projects and their success. This sent Alison into the field to study modern rice ecologies, both cultivated and wild, in far flung parts of Asia, from central China to Laos and the highlands of northern Thailand, through Bangladesh and Assam, remote parts of Odisha state in India, and the Western Ghats mountains along western coast of India. Her unique experience and expertise has meant that she attracted archaeological collaborations and samples for analysis from an even wider range of countries. She authored 29 academic papers or book chapters, in addition to 1 monograph, with many more still in the pipeline. For a list her published academic papers and chapters: see here.

While many have approached phytoliths typologically and metrically to attempt to look at morphological differentiation between domesticated and wild rice (e.g. bulliforms or double-peaks), Alison’s innovation was to focus on the plant communities that occurred with rice and were sampled in harvests, sub-sampled in crop-processing and ended up to systematically recorded, quantified and discriminated in the micro samples from archaeological sediments. In her fieldwork and analyses, her focus on plant communities and how human communities intersected these is evident. It offers a legacy for phytolith archaeology.

Ethnobotanical fieldwork in Thailand,
Nov. 2012: with Katie Manning.

Alison, herself was a key node in our community. Having worked in the archaeobotany lab as a post-graduate student and post-doctoral staff member for some 15 years, she was often the focus of discussions, both of science and of social life. She has also trained and supported numerous students, offered countless cups of tea, words of encouragement, and a warm sense of humour. She is warmly remembered.

I invite comments to be posted to this blog by those who knew and miss here. And I append below various photos of Alison in action.

Gyoung-Ah Lee and Alison on the Liu river, Henan, China (2006)

Alison collecting rice weeds in Bangladesh, Nov. 2013.

Nov 2011: Northern Thailand: Cristina Castillo (Left) and ALISON (right) with Karen rice farmers in Northern Thailand

Ellie Kingwell-Banham and ALISON WEISSKOPF in Maharashtra, India (Sept. 2010)

14 July 2004, IoA foyer on lab botanical shirt day: Phil Austin, Emma Harvey, Meriel McClatchie, Jon Digby, ALISON WEISSKOPF, Emma Jenkins. Alison was an MSc student at the time, and was apparnelty the original source of the idea for this day.  Below a full photos of the whole lab group.

Dorian, ALISON, and Deepika Tripathi at the IWGP in Thessaloniki (2014)

Indo-Pacific Prehistory Association conference, Siem Reap, Jan. 2014. Participants in session on "Foraging and Farming". Alison fifth from Left.

Early Rice and Its Weed Flora, Symposium at Peking University May 2011

Rice bulliform phytoiths and morphological change

In preparing for a recent Bangkok workshop on the archaeology of rice, I have collected some thoughts of the proposed methodology for tracking rice domestication using rice bulliform phytoliths.

Fan shaped bulliform phytoliths form along the veins of rice leaves. Rice (genus Oryza) has a distinctive shape although some fanlike bulliforms do occur in other grasses, but with different shapes. These are also sometimes referred to “motor cells” as these cells function, when alive, to fold and unfold the leaf and thus to control sunlight exposure, which in turn relates to amounts of photosynthesis and water evaporation from the leave. Once they are silicified and have become phytoliths they stop functioning so this tend to mean that the phytoliths come from older rather than younger leaves.

These are relatively large for single celled phytoliths (28-40 µm) and therefore fairly easy to recover and to spot in phytolith slides. Bulliforms have suggested to be useful for tracking domestication, separating subspecies japonica and indica, and for studying crop processing. Identification approaches relies on measurements and/or counting variation in the number of chips along the scalloped edge of the fan. In terms of crop-processing they are an indicators of leaf presence (i.e. straw), i.e from harvested rice and/or threshing by-production as opposed to husk phytoliths that represent dehuksing waste.

A study of bulliforms from Lower Yangtze archaeological sites suggest that they became large and more pronounced in their japonica morphological metrics over time, 5000 and 2000 BC, over the period when domestication was completed and grain size increased (Zheng et al 2003a). Measurements on controlled experimental crosses indicate the bulliform shape is influenced by numerous genes, with 16 genes (QTLs) suggested, but these QTLs only explain somewhere between 37% and 54% of the variation, suggesting the environment (growing conditions) play a major role (Zheng et al 2003b). No QTLs were correlated with the b/a ratio suggesting this may be largely environmental.

Bottom line on metrics: May be useful for separating indica from japonica when it can be assumed that rice was fully domesticated; and trends may be found alongside domestication. Further work is needed, especially on aus and more variation found in South Asia and more tropical varieties in Southeast Asia.

Bulliform scalloped margins: scale counts and domestication. Another approach to documenting bulliforms is to count the “scale-like” facets along the rounded edge of the “fan”. The fans in domesticated rices tend to have more facets. Initially Lu et al (2002) proposed that phytoliths with 9 or more facets are likely domesticated, while less than 9 are wild. This has been backed up by field comparisons of wild and cultivated rices in South China (Huan et al 2015) These studies indicate that example with less than 9 facets occur in cultivated rice and more than 8 occur in wild rice but the frequency differences are substantial (see below). 

This means in in time series data assemblages can be used to track changes over time (below). This is nicely demonstrated in a time series through the Early and Middle Holocene for the Lower Yangtze by Ma et al (2016). It should be noted also that current approach of Ma et al (2016) exclude from counts any assymetric phytoliths.

Time series of rice bulliform facet counts (% of ≥9) from Lower Yangtze sites (Ma et al 2016).

These data show a direction of travel over time that is similar to non-shattering, grain size increase and other indicators. However, much variation is hidden by the fact that difference between 8 facets (very common in wild rices) and 9 facets (probably the most common value in domesticated rices).

In addition, an explanatory mechanism is not yet firmly established, unlike established domestication traits such as non-shattering and seed size. While ~16 genes may affect bulliform shape, environmental factors are also essential, and domestication is ultimately about genetic changes that differentiate domesticates from their wild ancestors. Therefore it is essential to understand how much of this shift phenotypic response to environmental conditions as opposed to evolution. Huan et al (2015) suggest that the increase faceting in domesticated rice is due to increased use of leaf folding to control evaporation from leaves. They hypothesis that the erect growth habit of rice and drier growing conditions than wild rice would lead to increased faceting. If this is merely a phenotypic response then it becomes a less useful domestication indicator. But this can also be questioned, as ecological indices (see below) suggest that early rice in China was grown under wet, wild-like conditions (at least at Tianluoshan) and that erect growth habit and drier conditions occurred only from the later Majiabang period, and then returned to very wet conditions (Weisskopf et al 2015). So further work is needed to understand genetic and phylogenetic signal in bulliform facet variation as opposed to difference to due with habitat.

The bottom line: on the whole this looks like a promising and worthwhile complementary dataset, but it remains no substitute for morphological domestication data from macro-remains, as other environmental factors seem to be at play. In addition it is worth noting some studies that question the reliability of this approach.

Applications in India that raise questions over the universal applicability of this approach.   Harvey (2006 PhD, UCL) counted this chips on bulliforms from Chalcolithic sites in Orissa (Golbai Sassan and Gopalpur, dating 1500-1000 BC), both of which have domesticated rice (based on spikelet base data), and wet field ecology (further work by Kingwell-Banham 2015, PhD UCL). In this material the average number of chips is 8.6 and thus “wild “ according chip count standards used by Chinese researchers.This is out of agreement with the non-shattering spikelet base data, weed flora and the large village context all of which indicate fully domesticated, wet-rice based agricultural economies.

Saxena et al (2006) applied this to phytoliths from the lake sedimentary sequence at Lahuradewa, next to a Neolithic site in the Ganges plain of the same name. They reported both wild and domesticated bulliforms through the core is roughly equal proportions between 8600 and 3500 BP after which wild forms declined. While Lahuradewa is often discussed an an early site of rice cultivation in India, critical review suggest this was primarily wild rice gathering prior to ca. 2000 BC or so after domesticated rice became available through hybridization with japonica (the proto-indica hypothesis) (Fuller and Qin 2009; Choi et al. 2017; Murphy and Fuller 2017). Thus the phytolith data here appear out of agreement with macro-remains and rice genetics.

Applications in Southeast Asia and China that raise questions over the universal applicability of this approach. The initial introduction of this approach (Lu etal 2002) included a dataset on a see floor core between China and Taiwan, an area that would have been flooded after the Last Glacial. This palaeoenvironmental sequence produced rice phtyoliths- and rice would be expected in fresh water wetlands in such areas when they were above sea level. However, this included substantial numbers of the “domesticated” type. Is it realistic to believe that domesticated rice was already cultivated in flooded regions of Southeast China during the Last Glacial (LGM)? If so, then it must have been a dead-end experiment, as the evolution of domesticates rice is documented over the course the Early and Middle Holocene, starting anew apparently. However, if the bulliform faceting is responding to environmental conditions this LGM population may have nothing to do with human selection and domestication

The Loagan Bonut pollen core on Borneo near Niah Cave produced substantial quantities of rice bulliforms with high facet counts (i.e. “domesticated”) around 8000-7500 BP, but not later (Hunt and Premathilake2012). Is this also to be interpreted as a lost domestication of rice? Or could this be a particular situation in terms of environmental conditions that encouraged wild rice and more leaf folding and bulliform faceting?

Most of the above cases have all been presented as evidence of early farming, which would represent “stealth domestication” without other clear indicators for cultivation over the millennia leading to these nor continuing into subsequent period. In all cases phenotypic plasticity in response to environmental change needs to be considered, and realistically dismissed before domestication can be adequately diagnosed.

Rice husk phytoliths and morphological change

In preparing for a recent Bangkok workshop on the archaeology of rice, I have collected some thoughts of the proposed methodology for tracking rice domestication using rice husk phytoliths (the "double peaked" cells from lemma and palea).

The husks of rice are full of silica and often all the cells of silicified. The rows of cells on the rice husk include trapezoidal phytoliths the upper corners of which often form into peaks, as in the image below. These are diagnostic of the genus Oryza, although a few similar forms may occur more rarely in other grasses. These are often the most frequent form of rice phytolith. Because these derive from husk, disposed of after dehusking, they are an indicator of dehusking waste and useful in crop-processing studies. (See Harvey and Fuller 2005)

Size and shape of these varies and has been suggested to be useful in tracking domestication through measurements on populations (Zhao et al (1998)), although these are not definitive because of large degrees of overlap and because cell size is also impacted by environmental conditions. An explanatory mechanism for how these change during domestication has never been satisfactorily elaborated, although some relationship to grain size change seem plausible.

The proposed method for looking at double peak cells and domestication uses 5 measurement on each phytolith as defined below, left (from Zhao et al 1998)- note that H is measured twice on each side of the phytolith. Some of these are then used in squared form. These are combined in discriminant functions that are meant to assign individual phytoliths to like domesticated or wild (i.e. if the domesticated score is greater than the wild score: formula at right).

As originally developed, Zhao et al (1998) reported correct classification in their modern reference set was correct in >70% of test cases. The formulae were developed by taking Bayesian approach to discriminant function analysis. In an attempt to employ and extend this work, we attempted to replicate this in London with modern rice accessions, but found a correct identification in only 44% of cases (Harvey 2006). In addition measurements on phytoliths from Chalcolithic sites in Orissa (Gopalpur and Golbai Sassan) predicted a majority wild rice and on 39% domesticated. However these sites (dating 1500-1000 BC) have spikelets bases that indicate fully domesticated rice (100% non-shattering at Gopalpur and ~70% at Golbai out of a small sample size: unpublished UCL data from Kingwell-Banham 2015). This indicates that this phytolith discrimination method is unlikely to work in India, raising questions about what biogeographic contexts it would be useful in, if at all. One problem is that some of the variation in ancient cultivars may not be well represented in modern landraces. Indeed some of the measurements on archaeological phytoliths from Orissa fell outside the range of modern material, both wild and domesticated.

Also, against this method are two applications in China that have yielded results that are illogical with regards to what is known about rice domestication. As applied by Zhao (1998) to Diaotonghuan cave in Jiangxi and change from predicted wild in pre-ceramic layers and predicted domesticated dominance in early ceramic layers was found. At the time Zhao wrote this it was assumed the that advent of pottery was Neolithic and sometime in the early Holocene, but recent dating work on nearby Xianrendong and another South Chinese cave, Yuchanyuan, indicate the ceramics began to be produced around the Last Glacial Maximum or just after 18,000-16,000 BP. The ceramics at Daiotonghuan are comparable and thus this would re-date the alleged rice domesticated to ~18,000-16,000 BP, nearly 10,000 years earlier than potential sedentary, agricultural villages. An more plausible alternative explanation is that rice husk cells (and grains) changes shape in response to the major and rapid change in climate and atmospheric carbon dioxide levels that took place after the LGM.

As applied by Itzein-Davey et al (2007) in the Lower Yangtze region to a stratigraphic sequence of Qingpu rice bulliforms dating between 2300 BP and 1800 BO (i.e. Warring State through Han Dynasty era), they found the majority of double peaks were predicted as wild, often as much as 80% in some samples. Rice was certainly morphologically domesticated in the Lower Yangtze long before this and we would expect fairly intensive rice agriculture during Han times. These results also call into question this index.

Nevertheless plotting double peak measurements over a time series may provide a line of evidence for rice that is changing and evolving morphologically. This has recently been applied in South America to argue for a lost rice domesticationin the Amazon (Hilbert et al 2017). In the context of Chinese rice domestication the study of Wu et al (2014) demonstrated both that wild and domesticated predictions are very mixed on sites of early cultivation but also that there is trend for more double peak cells to fall towards the apparently domesticated end of the spectrum through time.

The bottom line: Variation in husk phytoliths exists but its significance in terms of domestication, varietal changes, cultivation ecology remains unclear and deserved further study.

The lost rice of South America

One of my pet interests is lost crops, or largely forgotten ones-- species that were important in the past which are either completely lost from cultivation today or very nearly so. They serve to remind us that the ethnographic present does not provide a full range of potential economic activities nor the full range of crops. They demonstrate that archaeobotanical evidence can provide important broadening of our list of potential crops to consider in future breeding and sustainability efforts. An endemic rice of South America can now be added to the list of lost crops.

This exciting find, that received quite a bit of media attention (e.g. in Science) was the recent report of a rice that was apparently undergoing morphological change, i.e. domestication. The archaeobotanical evidence, published in Nature Ecology and Evolution last month by Hilbert, Iriarte and colleagues as part of the ERC Pre-Colombian Amazon Scale Transformations project, comes 

from  phytolith anaylses through a stratigraphic sequence at the site of Monte Castelo in southwest Amazonia, dating to between 5300 BP and 700 BP, which includes rice husk phytoliths (the double-peaked cells) and bulliform throughout. The proportion of rice increased somewhat in the past 4000 years, but shifted especially towards a much higher ratio of husk types to bulliforms, suggesting the concerntration of husk phytoliths that one might expect from dehusking or harvested rice spikelets. It is at this stage that the shape of the husk phytoiths also starts to change, with phytoliths getting wider, taller and with more pronounced peaks. These are the kinds of changes that may be indicative of a domestication process and be a proxy for increasing grain size. The change takes places somewhere in the upper levels of the site, which are unfortunately not well constrained in dating, except being younger than 4000 BP and up to 700 BP or so. This suggests that the inferred domestication process took place or was even ongoing upto shortly before Colombian arrival from Europe and Amazonian population decimation.

One can quibble over whether changes in husk and inferred grain size increases must be human caused. The classic case of such a change in Chinese rice is decidedly NOT about domestication, as it takes place in sites South of Yangtze at the transition from the LGM to much warmer conditions, i.e. around 18,000-16,000 years ago. A full 10,000 years before the appearance on non-shattering rice spikelet bases appear-- domesticated by definition. When originally published by Zhao (1998 Antiquity) this was mistakenly dated to the Holocene, and thus inferred to represent domestication, but this falled a false equations (domestication because change is start of Holocene; start of Holocene because advent of ceramics could not possibly be any earlier). We now know the advent of ceramics transition in China took place around 18,000 years ago at Yuchanyan and possibly even earlier at Xianrendong, as already discussed for at least 7 years (e.g. Fuller et al. 2010). while domesticate rice, i.e. that was dependent on humans for dispersal, evolved during the middle Holocene, with the earliest large assemblage of non-shattering spikelet bases at Baligang by ca. 6500 BC and predominance in the Lower Yangtze as late as ca. 4000 BC (for a updated summary see here). It now appears most likley that the morphological change in husk phytoliths in South China was driven by the rapid climate change and especially the increase in carbondioxide which has major repercussions on plant productivity and morphology (see experimental work by Cunniff et al 2010), and thus the near doubling of carbondioxide that took place in the millennia just after the LGM (along with increasing temperature) ought to have hade major effects on rice productivity and aspects of morphology).

However, in the past 4000 years it seems unlikely that there were any climate or carbon dioxide shifts on quite the necessary scale, which makes the inference of a local rice domestication process much more likely.  A shift in grain size, however, would be expected to be accompanied by some selection for reduced shattering-- as this co-evolves in all of our better documented cereal domestications, most notably in Asian rice. Thus good flotation samples, with the required fine mesh of ca. 250 or 300 microns, ought to produce small charred rice spikelet bases. Recent experience suggests that everywhere we look, and do the requisite flotation, in tropical Asia, we find now that rice spikelet bases greatly outnumber charred grains and this tells us that they survive well and are archaeobotanically recoverable. This is also true to the major rice growing areas along the ancient Niger river. Some macro-remains would seem the obvious next step to pinning down more details about the evolution of this lost rice of South America. It would be highly unexpected if selection for larger grains did not take place alongside increases of indehiscent spikelet bases, as these co-evolve in other well documented cereals (as illustrated in a PNAS 2014 article).

It is also highly likely that increase in grain size implies management of soils, i.e. some sort of cultivation. This is contrary to the novel, but rather unconvincing, hypothesis of the authors that grains would have been encased in clay and dropped into the water. They cite as an ethnographic parallel systems of reseeding American wild rice (Zizania palustris) stands in the Great Lakes region of North America. But in that context there is no evidence for prehistoric grain size increase or domestication processes.The rice represented at Monte Castelo was likely a productive annual, as the authors note, and could have been encouraged by burning of competing vegetation after seeds are shed, in which case selection for seed size increase can be expected from the levelled playing field conditions of freshly cleaned fields which put a premium on rapid seedling establishment against competition from conspecific seedlings. 

South America boasts 4 indigenous wild rice species, Oryza alta, O. latifolia, O. grandiglumis, and O. glumaepatula, and only the last has annual ecotypes. South America's O. glumaepatula is also an AA genome, like domesticated Oryza sativa or Oryza glaberrima, and thus this suggests something inherently attractive for, or conducive to, domestication in the AA wild rices. Like Oryza species everywhere these are water-loving grasses, but there are still two ends of a spectrum from perennials in deeper water and annuals and places that are seasonally dry. Oryza alta, which can form mats along river margins, is a perennial (see, for example the photo at left lifted from Duncan Vaughan's 1994 monograph on the wild rices). Annual Oryza are prolific seasonal grain producers, and thus lent themselves easily to forager intensification, and it was such annuals that were ancestral of the early cultivars of Asian indica and aus rices, or African glaberimma (from wild annual O. barthii). By contrast perennial rices are less prolific grain producers due to investment in perennating stems, roots and more leaves. Thus Asian rices when available ought perhaps be expected to be used resources. The other continent with annual AA genome wild rices in Australia, where these are found in the northern parts. Lets see some archaeobotanical work carried out there, in the region of Oryza meridionalis, as one might expect parallel evolution for utilization and even management there.

20,000 yr old huts from Jordan

This report on Kharaneh IV, published in PLoSone  a couple of weeks ago, has a lot of people excited: well-preserved hut features from the early epipalaeolithic of the southern Levant, over 20,000 years old, are a pretty uncommon archaeological find. Most sits of such age provide a bunch of chipped stone, some animal bones and if one is lucky some wood charcoal. Of course, this period has already produced the remarkable Ohalo 2 over in Israel, with amazing plant preservation in burnt down huts of similar age, partial details of which were published in J. Arch Science by Ehud Weiss et al in 2008. One of the problems of Ohalo 2 has been there is so little to compare it with, apart from sites of much later periods. Now there is the opportunity. No plant evidence from Karaneh IV has been reported yet, although colleague here in London are working on it, Sue Colledge on the flotation samples, and a PhD student Monica Nicolaides is working on phytoliths and starch samples. We can expect some important results id due course, although it is unlikely to come close to Ohalo in terms of quantity and preservation in macros, but supplemented by much more systematically collected micros. Other exciting work on the faunal remains is taking place down the hall here, by Lousie Martin, Liz Henton, and Anna Spyrou, which will provide insights into mobility and seasonality.

The archaeology of this site has received plenty of media attention on-line already, and a useful summary at about.com.

Expanding Indus fibre crops

Two recent articles in Archaeological and Anthropological Sciences, report new evidence for species used in Harappan fibre work. Rita Wright and colleagues have reported evidence for jute textiles (Cochorus capsularis), based on analysis of fibre impressions preserved in ceramics. As with work done on plant impressions in pottery, this demonstrates that quite fine detail can be preserved in impressions, recorded in casts and studied with SEM. While we have perhaps long suspected jute, which is native to South Asia, was grown in the Indus period, seed finds from sites such as Rojdi (Weber 1991) were ambiguous as whether this species was cultivated, and processed for fibres.  Processing  involves retting (rotting in water), something I encountered a few years ago in the Son valley. My photo below shows a stack of harvested jute which is about to be weighed down with stones (visible in the water behind) for a week or two, before it is pounded to remove the fibres.

Posing for a photo with recently harvested jut that is about to retted  in the side channel of the Son river behind.

 Finds of textiles from eastern Iran published a few years ago by Irene Good, in the book  Ancient Textiles: Production, Craft and Society, included a couple examples of jute, as well as many of sunn hemp (Crotalaria juncea), which were also presumed to have been imported from the Indus to the east. Unfortunately as a small-seeded legume, recognizing the presence of sunn hemp in seed assemblages, especially as this crop and not a related weedy species, is not yet really possible, and could prove intractable. Taken together with evidence for flax seeds, and cotton in the Indus Valley [see my 2008 review pdf], as well as wild silk production (from the Assam silk moth), reported by Good & al. from Harappa in Archaeometry 2009, the Harappan civilization was quite the centre of textile crop diversity in the Bronze Age (compared to apparently only flax cultivation in contemporary Egypt or Mesopotamia). This adds weight to the notion that Indus exports, including those of the textually known Meluhha merchants of the Persian Gulf, included a range of cloth types.

Wild fibre sources were also important, and spun and woven net material from Shahi Tump, has also been reported recently by Thomas, Tengberg et al. in AASc. In this case, they appear to be using the local dwarf Mazari palms (Nannarrhops ritchiana). One of the excellent components of the paper is comparative study of palm phytoliths (admittedly of the limited taxa range that might be found in Pakistan), but which shows clearly that there is significant and taxonomically-informative variation in the spikey silica balls that palms produce. The next challenge will be doing more work on this variation and it taxonomic interpretation in the palm-rich tropics.

The rapid spread & differentiation of maize: new Peruvian data

New finds from the N. Peruvian coast report clear evidence for an earlier arrival of maize the region than previously thought (Grobman & al., PNAS), and with wonderful dessicated preservation indicating that they are popcorn varieties, but flourly varieties are also present. That there is a popcorn indicates quite rapid early varietal diversification, and these show already traits of South American rather Mesoamerican varieties. A direct AMS date puts these back to at least 4500 BC, so still a few millennia after perhaps 7000 BC date for the earliest maize in its Mesoamerican place of origin. The macro-remains are augmented by phytolith analyses and strach grains extracted both from the maize cobs and tools. Of methodological interest is the apparent discrepancy between dates on dessicated and dates on carbonized material, with the dessicated stuff being way to young. This may mean the dried stuff may sometime get contaminated with young carbon in some way (whereas the charred stuff has it true carbon fixed nicely by carbonization). Also of note is that maize is apparently not the most common plant find, and was not the dietary staple, although the present PNAS article focuses on the details of maize and we will have to await another forthcoming publication in Antiqiuty for more on the chillis, beans, squash and wild plants. Another discussion of this paper can be found in ScienceDaily news report from a couple of weeks ago.

Globalization of bananas in 3 acts. Recent updates

Bananas are an intriguing fruit. Quick growing, and tall, tropical herbs, rather than real trees, known pretty much everywhere today from the most temperate climes, as a typical and inexpensive table fruit, while in other places they serve as starchy staple alongside or even instead of tubers or cereals (and as the base for beer-brewing). Because most cultivated bananas are seedless hybrids tracking them archaeologically is difficult. Various lines of archaeological, linguistic and ethnobotanical evidence were pulled together a couple of years ago in a journal issue, while this year saw some updated syntheses, or at least attempts at synthesis. The origins of cultivated bananas seems to have focused on New Guinea, and the First Act can be regarded as the dispersal throughout most of tropical Asia. A PNAS article this summer, with 18 co-authors, across botany, linguistics and archaeology provided a model of integrating genetics and historical linguistics (with rather more limited archaeology) for tracking the early evolution, diversification of bananas, mainly in SE Asia [pdf]. I still have issues with how the hybridization between A and B genomes took place. The authors postulate an anthropogenic dispersal of M. balbisiana (B), and do not really deal with any potential role of South Asian balbisiana in hybrid bananas. Both parts of India (Orissa through Assam) and Sri Lanka have wild Musa balbisiana; Sri Langa has reports of wild M. acuminata too. It seems clear that Pleistocene (to early Holocene) humans in Sri Lanka were using and probably consuming wild bananas. In addition to the seeds from Beli-lena cave reported years ago by Kajale (in Harris and Hillman's volume Foraging and Farming). To this can be added new phytolith finds, in well-dated stratigraphic context from Batadomba-lena, published in Journal of Human Evolution this past summer. Ongoing phytolith analyses from other Sri Lanka caves, including some work here in London, will have more ancient Musa phytoliths to report soon. It may well be that wild Musa use in Sri Lanka was a dead-end with regards to early cultivars, but it seems premature to rule it out entirely.

Second act: the introduction of bananas and plantains to Africa. Probably the best general account of this is still to be found in the 1999 article by De Langhe and De Maret, and it was also addressed in several of the papers in the 2009 Ethnobotany Research and Applications issue on bananas. But for a summary that places this in the wider context of the translocation of crops, weeds and commensal animals across the Indian ocean, from Asia to  Africa see the paper I jointly authored with some other members of the Sealinks project, published in Antiquity this past summer, " Across the Indian Ocean: the prehistoric movement of plants and animals." The evidential lynch-pin for the a pehistoric/Iron Age translocation of bananas (or plantains) remains a single site in Cameroun with reported phytolths, Nkang. This limited evidence, of course, until or unless more is found may be open to critique-- which has been coming from some quarters of Africa archaeobotany. For the latest installment see the recent Neumann et al article in Quanternary International. A short blog here.

Third act: Gobailization via refigerator vessels and 20th century AD supermarket culture. For some account of the modern technology involved in the mass shipping and then ripening of supermarket bananas, specifically in New York city, see this recent blog at Edible Geography.The book Banana: the fate of the fruit that changed the World by Dan Koeppel, deals with this and much, much more; and I have discovered he has his own banana blog.

From domestication to Global Warming: the Early Rice Project in Archaeology International

2012 is the 75th anniversary of the founding of the London Institute of Archaeology (which is now part of UCL), and semi-popular journal Archaeology International has just launched a bumper double in honour of this. This also marks a reformatting of the journal and launch of an on-line edition, which is fully open access. In addition back issues are now available digitally for free, the three most recent are on-line already, and other should follow. This issue includes retrospectives from former students who have gone on to other lines of work and fame, retrospectives on past members of staff (e.g. the recently deceased John Evans), an introduction to our new satellite campus in Qatar, as well as article reporting on a small selection of research projects, from Neolithic Catal Hoyuk to Anglo-Saxon political landscapes, from the 14th century capital of Mali (Sorotomo) to early silverworking in the Andes. It also includes a summary of my Earl Rice Project (Fuller and Alison Weisskopf) including an up to date summary of rice domestication evidence from China, and our phytolith assemblage approach to reconstructing rice cultivation systems, which Alison in pioneering.

Here is our abstract: 

The Early Rice Project, at the UCL Institute of Archaeology, is clarifying the origins of Asian rice agriculture. In the Lower Yangtze region of China, we have found the tipping point when domesticated forms first outnumber wild types c.4600 BC. Investigations of assorted weed flora are also revealing how the cultivation of rice changed over time, with early cultivation in small, irregular, dug-out paddy fields in the Lower Yangtze from c.4000 BC, providing a means for the careful control of water conditions. We also work on early rice cultivation in Thailand and India. By better characterising how rice was cultivated across its entire range, we aim to model the ancient output of atmospheric methane from wet rice fields, as this was a potential contributor to the long story of human-caused global warming

The article and PDF are open access: here

New online Phytolith reference collection

A new searchable database of l phytoliths images has been made available by the Barcelona lab GEPEG (Research Group for Palaeocological and Geoarchaeological Studies). Find it here: GEPEG phytolith database. I have not  had a chance to explore it in detail, but it will doubtless prove useful. It has about 185 images in it, so it by no means comprehensive, and it includes archaeological as well as modern reference material. (And it reminds me that our UCL phytolith on-line gallery needs updating, as I have let in languish for a few years without additions).

Archaeobotanist honoured in Science

It is not everyday that archaeobotany received much 'mainstream' attention. But recently it did: Science on 2 July 2010 includes a profile of Dolores Piperno, one of our fields seniors figures in phytolith work and a pioneer in applying starch grains to the archaeology of the Neotropics.

More indicators of the early northern rice dispersal

More evidence from the phytolith research group at the Chinese Institute of Geology in Beijing indicates that rice dispersal rapidly northwards from its presumed Yangzte origins into the temperate Yellow River Basin. Zhang et al (2010) report in a recent BOREAS article. phytolith sequences collected from scraped archaeological sections at Quanhu, Yangguanzhai and Anban, all Yangshao sites in the Wei river tributary to the Yellow River. All three sites start from the Middle Yangshao on cultural grounds, and sediment AMS dates support the start of these sequences from 3700-3500 BC. They continue through the Longshan and sometimes later. Rice bulliforms and double peak cells occur throughout the sequences, although it should be noted that broomcorn and foxtail millet husks occur too (applying the enhanced identification criteria developed in the same lab, famously applied at Cishan), and usually millet husks far outnumber rice husks indicating that millet cropping (dry farming) dominated over presumably wet rice.

These data need to be taken alongside other, even earlier indications, that rice spread northwards already in the Early Yangshao, by ca. 4000 BC. My colleague Arlene Rosen has explored the geoarchaeological evidence for rice cultivation from the Early Yangshao onwards in the Yiluo Valley in a recent Geomorphology article (2008). In addition, towards the end of last year we published the archaeobotanical evidence from Nanjiaokou (by Qin Ling & Dorian Fuller, in Chinese in the Nanjiaokou monograph, 2009). This includes some rice, alongside the millets, from early Yangshao levels dated between 4500 and 3800 BC, although the earliest direct AMS date on a rice grain was from end of this range, 3900-3800 BC. Still all of this indicates that rice diffused rapidly from the South (in the Daxi/ Later Majiabang horizon) as it came to be intensively cultivated (and was still undergoing population-wise morphological evolution of domestication syndrome traits: see Tianluoshan links), and was adopted into the expanding economies of Yangshao millet farmers. 

New e-volume on the origins & spread of bananas

Just published is a special issue of the on-line, open access journal Ethnobotany Research and Applications, devoted to the "History of Banana Domestication". For those unfamiliar with the journal, it is worth watching, as it publishes a wide range of ethnobotanical papers, including several that have been relevant to studying crop origins and traditions of use. The journal is free, after one registers, and articles can be downloaed as PDF. This special banana issue arrises from a session at the Dublin World Archaeological congress. It starts on page 163 of Volume 7.

The contents are as follows:

Special Issue: History of Banana Domestication

Why Bananas Matter: An introduction to the history of banana domestication...Edmond De Langhe, Luc Vrydaghs, Pierre de Maret, Xavier Perrier, Tim Denham [link to this abstract]

Bananas and People in the Homeland of Genus Musa: Not just pretty fruit...Jean Kennedy

Combining Biological Approaches to Shed Light on the Evolution of Edible Bananas...Xavier Perrier

Differentiating the Volcaniform Phytoliths of Bananas: Musa acuminate...Luc Vrydaghs, Terry Ball, H. Volkaert, Ines van den Houwe, J. Manwaring, Edmond De Langhe

Relevance of Banana Seeds in Archaeology...Edmond De Langhe

Impressions of Banana Pseudostem in Iron Slag from Eastern Africa...Louise Iles

Banana (Musa spp.) Domestication in the Asia-Pacific Region: Linguistic and archaeobotanical perspectives...Mark Donohue & Tim Denham

Banana Cultivation in South Asia and East Asia: A review of the evidence from archaeology and linguistics...Dorian Q. Fuller & Marco Madella [download pdf]

Early Bananas in Africa: The state of the art...Katharina Neumann & Elisabeth Hildebrand

Bananas and Plantains in Africa: Re-interpreting the linguistic evidence...Roger Blench

Recent commentaries: the surge of archaeobotany

These have been a busy few months for the archaeobotany of domestication, or at least those keeping up with reading new publications. (The hard work producing the data was no doubt also busily spread out over the past few years). Since December we have seen new data on early foods in Peru, Maize in Mexico, North American crops, new thoughts on the wild food use at the start of Near Eastern domestication (Willcox et al., in The Holocene [or GCW's site]), new early evidence for Panicum miliaceum cultivation in Gansu, and then even earlier dates in central China at Cishan, and the evidence on the evoution of domesticated rice from Tianluoshan. Well-preserved granaries (the oldest) from the PPNA of Jordan when cereals were still morphologically wild but probably cultivated, have also been noted (blog here). The vast majority of these studies appeared in big impact journals (PNAS, Science), and these have of course, attracted some wisened commentaries. Here are some links to those commentaries but (without any particular further comments on them).

T. Douglas Price, commenting on Smith & Yarnell, in PNAS 106 (16): 6427-6428

Gary Crawford, commenting on Lu et al , in PNAS 106 (18): 7271-7272

Martin Jones & X. Liu in Science (8 May 2009), commenting on Tianluoshan, and early Chinese millets.

Expanding African phytolith potential

An article in the latest Annals of Botany, by John Mercader et al., presents results from a study of phytoliths from modern vegetation in the forests near Lake Nisiala in Mozambique. This is an important baseline and background study, which should contribute to the potential application of phytolith analysis in archaeology and palaeoenvironmental studies in East Africa. Perhaps most importantly they have considered issues of expected relative preservation rates for different morpotypes and the patterning of phytolith assemablges representing different families, even in the absence of true species diagnostics, which should allow for inferring the vegetation type of the Miombo woodlands. Combined with a few other, widely dispersed phytoltih moprhotype studies in parts of Africa, listed below, this represents another important step on the path of developing systematic archaeobotany in sub-Saharan Africa. Other previous background studies, include:

• Bremond L, Alexandre A, Peyron O, Guiot J. 2005. Grass water stress estimated from phytoliths in West Africa. Journal of Biogeography 32: 311–327.
• Bremond L, Alexandre A, Wooller MJ, et al. 2008. Phytolith indices as proxies of grass subfamilies on East African tropical mountains. Global and Planetary Change 61: 209–224.
• Runge F. 1999. The opal phytolith inventory of soils in Central Africa – quantities, shapes, classification, and spectra. Review of Palaeobotany and Palynology 107: 23–53.
• Runge F, Runge J. 1997. Opal phytoliths in East African plants and soils. In: Pinilla A, Juan-Tresseras J, Machado MJ eds. The state-of-the-art of phytoliths in soils Madrid: Centro de Ciencias Medioambientales. 71–81.

Millet Watch: Even earlier dates for Chinese Panicum

Published on-line last week in PNAS was a major new archaeobotanical study of the site of Cishan in central China, which utilized husk phytolith identification methods-- recently developed (published in PLoSone in February)-- and chemical differentiation between foxtail millet and broomcorn millet-- newly developed in this paper. Cishan is well-known site names, generally dated to sometime around 6000 BC, and regarded as type sites one of the early Neolithic cultures of northertn China. There has long been confusion over exactly what sort of millet remains were preserved there, based on the report from previous excavations in the early 1980s, of large storage pits full of 'millet' which variously been interpreted as Panicum or Setaria, but which never were studied or published within any real basis for identification (see for example the recent Cantab. review on early millets). Now this paper by Lu Houyuan and colleagues from the Institute of Geology at the Chinese Academy of Sciences, have cleared this matter up: broomcorn millet was the basic staple at Cishan, at least at its earliest period, and Setaria italica, therefore appears to be a later addition to the crop repertoire, at least in this region. Indeed, this also appears to be the case fruther west at the later Dadiwan, where Panicum cultivation, and especially consumption (by people and their dogs), goes back to 5900 BC or so (work by Barton et al., on which I blogged previously - and with a reply from Barton).

The other major bit of exciting evidence from this new Cishan study are the radiocarbon dates that put the earliest storage pits and millet at the site back to 8000-8500 BC. This would seem to push millet back about 2000 years! (Giving it an even bigger head-start, over rice, as a crop). Other dates are as late as 5500 BC, suggesting a very long (but continuous ?) occupation at Cishan. As any archaeologist will feel, the long span of time covered by the Cishan dates raises many questions about the nature of settlement, society, and site formation over this period.

This study has many strengths (especially with regards to the careful and innovative lab methodologies) but it also has a few weaknesses. These include the unstated/unquestioned assumptions about the ecology of the wild progenitor-- points I raised earlier in relation to Dadiwan-- although I tend to agree that large grain stores imply a regularly cultivated stock. There is also a lack of comparably detailed archaeological work: what is the settlement pattern and material culture that goes with these early millet cultivators and how does it change over the millennia between 8500 and 5500 BC? The latter is, of course, not a question aimed at the authors of this study, but at Chinese archaeological colleagues. Prof. Lu and colleagues have provided some powerful new tools for finding and identifying early millets, but the next step is to deploy these methods in some joint projects with archaeologists so that open excavations, ceramic and lithic toolkits can be assessed alongside the phytoliths. In short, we need more archaeobotany like this to be part of archaeological projects.

My final quibble, as is so often the case, is that we need to be cautious with use of the term 'domestication'. Was the millet at Cishan cultivated? Probably, for the reason that it was stored in large quantities as a staple food. Had it undergone morphological domestication, for non-shattering, larger grain sizes, possible changes in dormancy?... More research that links phytolith morphologies to the domestication process (selection pressures) and domestication traits is needed (this is true of most cereal crops, not just millets!). It seems unlikely that phytoliths will answer all the questions about domestication (like non-shattering). Where on the pathway to domestication was the Cishan millet, and how did it change and move along that evolutionary trajectory over the 3000 years the site was occupied? (Or are we to infer the process was all finished?) The lesson of Tianluoshan is that early crops were still evolving, and this is a protracted process that we should be able to see and track, once we develop the right tools with which to see this-- somes lesseon might be drawn from other crops like wheat and barley for which it is just becoming possible to track the mode and rate of domestication [Ann. Bot. paper]. These new phytolith and chemical criteria, developed in this Cishan study, are an important part of the tool kit that we need for domestication studies in millets. We need more data and integration together with additional methods (macro-remains, isotopes). So the fun begins, the quest for millet domestication.