loo Muhlenbergia, Volume 8 



Euphorbia glyptosperma Engelm. Bot. Mex. Bound. 187. 



1859- 

 North slope near Desert Laborator}', August 31, 1908, no. 

 2^11. This is E. capitellata of Thornber's list, ''Vegetative 

 Groups of the Desert Laboratory Domain," in Spalding, Carne- 

 gie Institution Publication 113. This is easily the most abund- 

 ant species about the Tummamoc hills, but well limited to the 

 rocky, basaltic slopes of residual clay soil. While it is not cer- 

 tain that all individuals vegetate twice annually, the species cer- 

 tainly blooms both in winter and in summer, as do many other 

 desert perennials. It has a semi erect habit, recurved branches, 

 and a perennial root. Typical leaves are trowel-shaped, that is, 

 elongated, rounded at both ends, and slightly tapering toward 

 the apex. Some variants with oblong-linear leaves were found, 

 but these were only two or three in number and could not be 

 separated on any other ground. Evidently it is one of those 

 offshoots more or less definitely exceeding what is known as 

 individual variation, yet by far too small to constitute specific 

 variation. Such cases are frequently found in nature among 

 abundantly represented species. 



Euphorbia Florida Engelm. Bot. Mex. Bound. 189. 1859. 



Tummamoc hill, August 31, 1908, no. 2^12. This is a 

 small, slender, erect summer annual, sparingly furnished with 

 long, linear leaves. The flowers are large for the genus as here 

 represented, the terminal ones nearly white, but the lower sub- 

 axillary ones are often of a deep rose color. When suffering for 

 want of moisture the long leaves, ordinarily held in a horizontal 

 or ascending position, become very limp and drop until they 

 hang vertically. The species is well distributed on the stiff soil 

 of the hill slopes with E. glyptosperma^ but is nowhere abund- 

 ant. 



Euphorbia Preslii Gn.ss. Fl. Sic. Prod. 1: 539. 1827. 



Santa Cruz river bottoms, August 25, 1905, no. 2^1^. An 

 erect annual, one to two feet high, abundant in rich, well wat- 

 ered soil of the flood plain. The conspicuously serrate central 

 leaves are much larger than the branch leaves. 



