814 PROCEEDINGS OF THE AMERICAN ACADEMY. 
4-merous, staminate and perfect: legume with glabrous valves ; margin 
armed with very short incurved prickles. — Contrib. U. S. Nat. Herb. v. 
141. — On foot hills and in mountain woods above Cuernavaca, Pringle, 
nos. 6200, 6385 (distrib. by clerical error as c@rulescens) ; and between 
Guichocovi and Lagunas, Oaxaca, Nelson, no, 2746. A beautiful and 
very distinct species. 
= = Leaflets 8 to 10 mm. long. 
a. Branchlets and peduncles strigillose or covered with a sparing sub-appressed 
scabrous pubescence. 
1 16. M. Nelsonii. Scabrous-puberulent shrub, 3 to 6 dm. high: 
branches woody, covered with a dull gray bark; branchlets warty- 
roughened: petioles short, scabrous-puberulent; pinnz 1 pair; leaflets 
5 to 11 pairs, broadly oblong, rounded at both ends, appressed-ciliate, of 
firm subcoriaceous texture, slightly lucid, 7 to 9 mm. long, 4 mm. broad, 
when young finely pubescent upon both sides but sometimes early 
glabrate, or perhaps glabrous at first, often (especially the lowest one) 
strigillose beneath: peduncles considerably exceeding the petioles, some- 
what pubescent and strigillose: globose heads 10 mm. in diameter; 
bracts shorter than the buds, inconspicuous; flowers 4-merous, perfect 
and staminate: fruit light-colored, oblong, 2 cm. in length, 6 mm. in 
breadth, 3-4-jointed, hispid throughout with spreading curved bristles. — 
Collected in fruit by Dr. Edward Palmer near Acapulco, between 
October, 1894, and March, 1895,_no, 88, and in flower by Z. W. Nelson, 
between San Geronimo and La Venta at 665 m, altitude, 13 July, 1895, 
no. 2775 (in herb. U. S. Nat. Mus.). A species nearly related to 
the Lower Californian M. Xanti, but differing in its more sparing and 
scabrous pubescence, and much shorter bracts. Palmer’s specimen 1s 
armed with straight scattered spines, while Nelson’s is unarmed, yet 
their identity cannot be doubted. 
- 6. Pubescence of branchlets and peduncles more copious, tawny-tomentose, 
spreading, softer in character. 
tu 17. M. Xanti, Gray. Leaflets 4 to 9 pairs, oblong, pubescent 
upon both sides, cinereous beneath, scabrous-ciliolate upon the margit) 
- about 8 mm. long: bracts exceeding the buds and conspicuous in the 
young heads: legume 2-4-jointed, stipitate, 2 cm. long, covered with 
fine pubescence and short scattered sete both upon valves and margins. — 
Proc. Am. Acad. v. 157; Benth. Trans. Linn. Soc. xxx. 396; Brandege® 
Proc. Calif. Acad. Sci. ser. 2, iii. 133.— Lower Calif. near Cape St 
2 Lucas, Xantus, no. 29; Brandegee, no. 183. 
