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*porshoat MUSEUM LEAFLETS 
AL NE 
HARVARD UNIVERSITY 
CamprinGr, Massacuusetts, Ocroper 29, 1965 Vou. 21, No, 
IDENTIFICATION OF THE POLLEN 
OF MAIZE, TEOSINTE AND TRIPSACUM 
BY PHASE CONTRAST MICROSCOPY 
BY 
Henry [rRw1n anp Etso 8S. BaARGHOORN 
In early studies, Firbas (1987) measured the long axis 
of grass pollen grains from domestic and wild types in 
Kurope and established 85 as a division between the 
two, those larger being considered domestic. Subsequent 
studies, both in Kurope and America, often showed this 
dividing line to be invalid. 
In an effort to distinguish between the pollen of maize, 
teosinte and Tvipsacum, Barghoorn, Wolfe, and Clisby 
(1954), investigated the pore-axis relationship in these 
grasses. A ratio of 5.7 or greater appeared to separate 
maize from the other two. Measurement of the pore in- 
cluded the annulus. However, this ratio has been criti- 
cized by Kurtz, Tucker, and Liverman (1960), who 
demonstrated that, under certain eet the pore- 
axis ratio of maize dropped well below 5.7. Their choice 
of a peculiar type of maize, Bikini sien probably 
prejudiced their findings. Further work suggesting that 
the pore-axis ratio is sometimes invalid as a distinguishing 
criterion was carried out by James Langham and Donald 
Whitehead of Williams College. They also investigated 
simple axis measurements, summarized in Text Figure 
