Tuesday, 25 August 2009

Millets and Mistakes

In Last week's Science the journalist Andrew Lawler, published an extended series of News Focus articles on Chinese civilization. The central piece focuses on the origins of civilization, highlighting for example the impressive urban settlement of Liangzhu (a kind of walled Neolithic Venice, many centuries before the Shang Dynasty) which ought to be better known to world archaeology than it is. (I had my own tour of some of the mutliple sites that compose it, and its multimedia museum, with site director Liu Bin in July). Also of note is his one page sidebar entitled "Go East, Young Archaeologist" on the specialists trained outside China, which features Jimmy Zhao, who has been instrumental in getting serious archaeobotany established in the minds and manners of Chinese archaeologists, and has been promoting flotation in China for the past decade.

What I would like to pursue here, however, are some observations on archaeobotany, and pick out some mistakes or misleading statements, with reference to the origins of millet agriculture which features in another sidebar, "Millets on the Move." Lawler begins which a point that seems to look increasingly true, that millet(s) were cultivated and presumably domesticated before rice, and were the staple foods of the northern China region where the classic Chinese civilization later emerged (focused on Erlitou rather than Liangzhu). He makes reference to the recent early dates (ca. 8000 BC) associated with Panicum miliaceum husk (lemma/palea) phytoliths reported from storage pits at Cishan (blogged previously). However, I must disagree the there is any hard evidence that the Panicum miliaceum at Cishan was morpholoigcally domesticated (i.e. non-shattering, with marked increased grain size, etc.), nor is there even clear evidence for cultivation, unless one assumes that large stores could only be ontained from cultivation, which in turn implies that we know the Early Holocene wild ecology of this species (which we don't) and that it did not form extensive collectible stands, as wild wheat, barley or rice or teosinte do (see discussion on my earlier Dadiwan blog and comment from L. Barton). I also must reiterate that there is much about the archaeology of the Cishan find (stratigraphiy, cultural context, and dating that require further work.

A lack of scientific clarity in Lawler's piece, however, is indicated in that millet is always used in the singular and the species (there are two major domesticates in ancient China) is never specified. And things get worse... as Lawler explored the hypothesis (favoured by Martin Jones and Cambridge millet group) that Panicum miliaceum (but NOT Setaria italica) spread before 5000 BC acroos temperate Eurasia from China to India. This hypothesis is plausible, but there is not yet any good clear data for this, only hints that it might yet emerge from ongoing and unpublished genetic work. Lawler acknowledges an alternative, which I would favour, that Panicum may have had a seperate domestication in the west somewhere near the Caspian and Black Seas. Well-dated, clearly-identified and numerically large assemblages of Panicum miliaceum outside China are mostly millenia later. To illustrate his case, Lawler produces a map which shows a major lapse in scientific clarity:

This map, although redrawn from that in Hunt et al (2008), is extremely mis-leading, especially when coupled with the text that hook-line-and-sinker swallows the notion that "millet" spread in the early Neolithic to Europe, without apparently realzing what "millet" is (or millets are). Millet is more than one species anyways despite the English misnomer-- in modern India one can find 12 domesticated species of "millet" in cultivation, with several more restrcted to Africa). The early dispersal of "millet" that Martin Jones favours, applies to broomcorn millet (Panicum miliaceum), as does the recent early find at Cishan, although Neolithic North China also boasts foxtail millet (Setaria italica), by about 6000 BC or so. For the map of Lawler, however, the "millet" in the caption actually means the genus Panicum or the genus Setaria, and does not require that these be cultivated or domesticated finds. What is most grevious in this map are the dots in Western Asia and Egypt. This map in its original, illustrated all reports identified to genus level of Setaria or Panicum-- both of which are major genera of grasses with multiple wild species-- in which the error margins of calibrated radiocarbon dates may place them as early as 5000 cal.BC (although often the dates are likely to be later). The dots in Western Asia, include sites such as Abu Hureyra in Syria, which is a well-known site to students of early wheat and barley agriculture. At this site it is argued (by Hillman et al. 2001) that wild rye and perhaps two-grained einkorn were brought into cultivation in the Late Pleistocene during the Younger Dryas, while later PPNB levels have evidence for domesticated wheats, barley and other Near Eastern crops. "Millet" is represented at this site by small number of wild Setaria, of either S. pumila or S. verticillata, and certainly not Setaria italica nor Panicum miliaceum. Other dots in Syria and Cyprus include Tell Mureybit, El Kowm, Bouqras, and Khirokhitia, which Lawler has now awarded domesticated Chinese millet in the Pre-Pottery Neolithic. Meanwhile, three dots occur in Egypt, representing Early Holocene "Neolithic" sites like Nabta Playa. These sites are Neolithic in the sense of having pottery but not in having agriculture. Archaeobotanical evidence from these sites shows wild savannah grass gathering, including wild sorghum and a range of other species, including wild Panicum sp. and wild Setaria sp., but there is certainly no suggestion that these were cultivars or related to S. italica or P. miliaceum. While Hunt et al (2008: S6) were explicit in trying avoid the pitfall of "over representing.... securely identified domesticated finds", Lawler appears to have jumped headfirst into this pit!

The dot in Iran (representing Daulatabad R37) is also problematic as early millet finds there are more likely local wild species, while evidence for domesticated Panicum miliaceum is probably later form the latter Third Millennium BC at Tepe Yahya (a time period which fits with the reports of broomcorn millet appearing in Yemen before 2000 BC-- see the recent Boivin/Fuller review dealing with the prehistory of Arabia). A more detailed and critical look at the sites in Europe would show that these also include numerous Setaria sp. and some Panicum sp. reports that are of local wild species. In addition, quantities of reported Panicum miliaceum are extremely low and it remains entirely plausible that these represent wild, weedy Panicum miliaceum subsp. ruderale as a weed rather than domesticated broomcorn as a crop-- a point admitted in the Hunt, Jones, et al. paper from which the map derives (see page S14). Of course there is a bias towards focuing of wheats and barley in European archaeobotany, and careful documentation of the early Panicum has been less thorough. More archaeobotanical efforts are needed in this direction, like that being pursued by the Cambridge millet group, but dumbing-down for, and misleading, the educated readers of Science is not.

1 comment:

Lǔkèsī Bādùn said...

equally troubling, i might add, is the photo!! though it looks like a "millet" (pearl millet i suspect?) it's nothing do do with either of the eurasian millets, and it certainly isn't broomcorn! other than that, i enjoyed seeing such coverage in science, and i'm grateful to the author for this extensive (if inexact) journalism.