CHROMOSOME NUMBERS IN 
CHIHUAHUAN UMBELLIFERAE 
BY 
LINCOLN ConstaNCcE!, Tsan [anc CHUANG? 
AND Ropsertr A. Byer, Jr.® 
In his ethnobotanical studies of the ‘Tarahumara cul- 
ture in the Sierra Madre of southwestern Chihuahua, 
Robert A. Bye, Jr., made a concerted and very success- 
ful effort to obtain material of Umbelliferae for chromo- 
some counts. The results of these counts (made by 
Chuang) are shown in the accompanying table and Plate 
LXV, and some brief comments (by Constance) follow 
(Table LT and Plate LXV, a-k). 
Donnellsmithia C. & R. The report on D. silvicola is 
new: that of 7=20 for D. ternata disagrees with one of 
n=21 for the same taxon (Constance, Chuang and Bell, 
in press). Chromosome numbers in this genus are still 
confusing. Counts made on eight specific taxa have 
yielded the following haploid numbers: 11, 14, 20, 21, 
22, 40, 42, 44. Thus, both D. silvicola and D. ternata 
are probably tetraploid. 
' Department of Botany, University of California, Berkeley, Cal. 
* Department of Biological Sciences, Illinois State University, 
Normal, II]. 
3 . ae . . 
Botanical Museum, Harvard University, Cambridge, Mass. 
C241 | 
