8f2 PROCEEDINGS OF THE AMERICAN ACADEMY. 
legume about 3-jointed, finely pubescent upon the valves and strongly 
setose on the margin. — Benth. in Hook. Lond. Jour. Bot. v. 85, & 
Trans. Linn. Soc. xxx. 392. — Borders of Oaxaca and Chiapas, Nelson, 
no. 2858; Guatemala, Skinner, acc. to Benth., J. D. Smith, nos. 3758, 
6132; Costa Rica, Ujaras, Oersted, acc. to Hemsl. 
9. M. Pittieri, Micueri. Pinnz always 2 pairs; leaflets 5 to 6 
pairs, ovate, ciliate: infra-stipular spines recurved, caducous: peduncles 
axillary, solitary, exceeding the petioles: bracts nearly or quite as long 
as the corolla.— Bull. Soc. Bot. Belg. xxx. 294 (whence description is 
compiled). — Near Rio Jesus Maria Puntarenas, Costa Rica, Pittier, 
no. 502. Not seen by the writer. 
. ++ ++ Leaflets oblong. 
= Margin of legume bearing very short recurved hairs; valves pubescent and 
often strigillose. 
vs 10. M. affinis, Rosrnson. Pinne 1 pair; leaflets 8 to 12 pairs, 
“ acutish: peduncles shorter than the petioles. — Bot. Gaz. xvi. 341. — 
Grassy land near Mazatlan, W. G. Wright, nos. 1218, 1265; hillsides 
near Tequila, Pringle, no. 5453; Colima, Palmer, no. 131 (coll. of 
1897); wet soil near Cuernavaca, Morelos, Pringle, no. 6662. 
== Valves of the legume glabrous; margins setose with straight spreading 
bristles: pinne 1 or more commonly 2 approximate pairs. 
11. M. pudica, L. The well known sensitive plant of cultivation, 
very variable as to pubescence: occasional scattered spines as well as 
the infra-stipular usually present. — Spec. i. 518; Benth. Trans. Linn. 
Soc. xxx. 397, where extensive synonymy is given. — Common through- 
out tropical America from S. Mexico southward; Orizaba, BourgeaYs 
no. 2400; Vera Cruz, Bourgeau, no. 1759, C. L. Smith, no. 999, Nelson, 
nos. 159, 393; Costa Rica, J. D. Smith, no. 5767; Honduras, J. D. 
Smith, no. 5219, Niederlein; Panama, Fendler, no. 96, Seemann, 00 
102. (Also extensively naturalized in the warmer countries of the Old 
World and said to be spontaneous in some parts of our Southern States.) 
+ + Stems decidedly ligneous. 
++ Spines infra-stipular or scattered: pinne 1 or 2 pairs: fruit (where known) 
rather narrow, not exceeding 8 mm. in breadth. 
== Leaflets 13 to 25 mm. long. 
a. Branchlets and peduncles scabrous-pubescent. 
12. M. tricephala, Cuam. & ScutEcut. Spines straight: leaf- 
se 
lets 10 to 15 pairs, ovate-oblong, 1—-2-nerved, glabrous above, strigo 
beneath, 1.2 cm. long. — Linnea, v. 591; Benth. Trans. Linn. Soc. 
& 
