ROBINSON. — SPECIES OF MIMOSA. 307 
to repeat here the well-known generic characters. A word may be said 
regarding the derivation of the name. At least it may be stated that no 
satisfactory etymology has thus far been suggested. The traditional 
derivation from mimus, a mimic actor, which has for many years been 
handed down in our text-books, was early given by Tournefort. The 
name, however, dates back of Tournefort, and his explanation is in 
several regards unsatisfactory. In the first place no ordinary rules of 
word-composition would lead to the formation of a Latin substantive 
ending in osa from another ending in us. Nor if such derivation could 
be accomplished does it explain the traditionally long o of the penulti- 
mate syllable. Prof. J. B. Greenough has suggested a possible connec- 
tion with a theoretical (although never actually used) active participle 
pipovoa from pyéowa. Further light upon this subject is desired, but 
the writer has not had an opportunity to follow the matter historically 
beyond a few of the more accessible works. Any derivation from py, 
an ape, seems also to offer philological difficulties. 
No authentic specimen of the doubtful M. arcuata, Mart. & Gal., 
has been seen, but from the original description, Bull, Acad. Brux. x. 
2, 308, it would seem near to, if not synonymous with, Mf. biuncifera, 
enth, 
M. cemmnata, DC. (Prodr. ii. 427; A. DC. Calques des Dess. t. 
205), is wholly dubious. 
bg. 1. AsTaTanpRa, n. subg. Flowers polygamous in the same 
head; staminate flowers with twice as many stamens as segments of 
the corolla ; perfect flowers with stamens of the same number as the 
Segments of the corolla. 
Sd. Me. tequilana, Warts. Low branching tawny-hirsute annual, 
nee. with weak scattered spines: pinnew 1 pair ; leaflets one or two 
Pairs upon each secondary rhachis,* obovate, rounded and mucronate at 
the apex, thin, sensitive, glabrous above, appressed-villous with tawny 
hairs beneath : flowers in small ovoid heads: corolla 3-4-toothed: calyx 
obsolete : legume armed on edges and valves with weak straight spread- 
“8 spinescent bristles. — Proc. Am. Acad. xxii. 409 (1887).— Hill- 
sides, Tequila, Jalisco, Palmer, no. 378, August to September, 1886, 
and in the same locality, Pringle, no. 4596, Placed in the Modeste by 
Dr. Watson, who seems not to have noted the two kinds of flowers with 
differing androciums, 
* 2 When the number of leaflets is given in this paper, it applies merely to those 
Pon @ single secondary rhachis, not to those of a whole leaf. 
