ROBINSON. — SPECIES OF MIMOSA. 317 



Var. zygophylloides. Leaflets reduced to a single terminal pair 

 on each secondary rhachis, 4 to 6 mm. long, slightly rounder, thicker, 

 and more veiny than in typical form. — Collected in flower at Man- 

 zauillo, Colima, by Prof. M. E. Jones, 25 June, 1892, no. 193 (herb. 

 U. S. Nat. Mus.). The peculiar arrangement of the leaflets here 

 corresponds to that in M. Rosei, characterized below, but the leaflets 

 themselves, even at full maturity, are not more than a third as large. 



24. M. Rosei. Unarmed, glabrous : branches striate : stipules subu- 

 late; petiole and primary rhachis glandless, about 13cm. long; pinnae 



4 pairs ; secondary rhachises stipellate and geniculate near the base, 

 12 to 14 mm. long; leaflets, mostly a single pair, rhombic-obovate, 

 obtuse, glabrous, deep green above, not lucid, somewhat paler green 

 beneath, 15 to 22 mm. long, two thirds as broad : spikes axillary, 

 solitary, (including short peduncle) C cm. long in fruit : legume (scarcely 

 mature) linear-oblong, acuminate, flat, thin with firmer margin, about 

 8-jointed, 7 cm. long, 5 mm. broad ; the segments sharply limited by 

 straight transverse lines. — Collected in young fruit by Dr. J. N. Hose, 

 at Balanos, Jalisco, 10 to 19 September, 1897, no. 2919, 



= = = Fruit tomentulose but not setiferous. 



25. M. purpurascens. Habit, thorns, &c., much as in M. laxi- 

 Jlora : pinnae 4 to 5 pairs ; leaflets about 4 pairs, 4 to 6 mm. long, 

 puberulent (under lens) below; rhachises puberulent: spikes solitary or 

 geminate, 4 cm. long including short peduncle ; flowers subsessile, dis- 

 tinctly purplish : calyx finely pubescent : pods about 5-seeded, oblong, 

 acute, 3.5 cm. long. — M. laxi'Jlora, Braudegee, 1. c, at least in part, 

 not Benth. — Lower Calif., at La Paz, Brandegee, 4 February, 1890, 

 no. 185, in flower, and at Purisima, 13 February, 1889, in fiuit, secured 

 by same collector. Some old fruit collected by Xantus in 1873, appears 

 to be of the same species. Type in herb. Brandegee. Although near 

 M. laxijlora, this plant cannot be satisfactorily referred to it. 



■*- •<- Leaflets 4 to 15 (rarely 20) pairs, linear to elliptic-oblong, mostly more 

 than twice as long as broad: fruit not exceeding 1 cm. in breadth: shrubs, 

 mostly armed. 



++ Pods tiiin, sometimes setose but not tomentose ; segments much broader 



than long. 



26. M. polyantha, Benth. Shrub 1 to 2 m. high : spines stout, 

 recurved, solitary beneath the axils : leaves not fully developed at time 

 of flowering : pinnae 2 to 3 pairs ; leaflets 4 to 8 pairs, oblong, small, 

 glabrous above, sparingly appressed-pubescent or glabrous beneath, about 



5 mm. long: spikes numerous, 4 or more fascicled at each node of the 



