76 Contributions from the Gray Herbarium 



(1897). Arizona: limestone Ledges, foothills of the Santa Rita 

 Mts., 25 .June 1884, PringU (cottpb coll.: GK). T. 2. Fig. 47. 



94. 2. P. Tweedyi Britton. Stems numerous, often very crowded, 

 erectish or spreading from a fruticulose base, finely incurved-pu- 

 berulous, 4 L9.5 cm. long. Leaves (except the lowest) linear, suba- 

 cuminate at each end, mucronulate, sparsely incurved-puberulous 

 chiefly along the slightly revolute margin, 1-nerved, 9-18 mm. long, 

 0.7-1.8 nun. wide, on petioles 0.5 mm. long; the lowest obovate- 

 oblong, obtuse, mucronulate, cuneate at base, 4-12 mm. long, 1.3-4 

 mm. wide. Racemes extra-axillary, 1-1.3 cm. long, 3-6-flowered, 

 straight ish or slightly geniculate. Flowers 4 mm. long. Upper 

 sepal elliptic, obtuse, incurved-puberulous, submucronulate, 2-2.3 

 mm. long; lower sepals 1.4 mm. long, sparsely puberulous and cilio- 

 late. Wings obovate, rounded at apex, cuneate at base, glabrous, 

 the veins reticulate toward midrib but free at apices, 4 mm. long, 

 1.8 mm. wide. Keel saccate near middle, 3.5 mm. long, its rostrum 

 slightly descending, obtuse, 0.5 mm. long. Upper petals oblong, 

 obliquely retuse at apex, 3.2 mm. long. Capsule oblong, barely 

 emarginulate, scarcely stipate, obliquely striate, subsparsely or 

 densely incurved-puberulous, 4.5 mm. long, 2.7 mm. wide. Seed 

 subsilky-pilose, 3 mm. long. Aril as in P. Lindheimeri, 2 mm. high, 

 corneous throughout, the umbo with slight anterior boss, the 2 

 lobes app'ressed, linear-oblong, slightly bifid near apex or entire, 

 1.5 mm. long. Britton! in Wheelock, Mem. Torr. Club ii. 143 

 (1891). P. arizonae Chod. var. tenuifolia Chod.! Monog. ii. 109 

 (1893). Texas: Tom Greene Co., 1879, Tweedy (type coll. of 

 P. Tweedyi: G). Arizona: Babocomori Creek near Ft. Huachuca, 

 May 1882, Lemmon 2641 (type coll. of P. arizonae var. tenuifolia: 

 BG); southern part, 1881, Lemmon 497 (G). It is possible that 

 Lemmon 2641 really came from northern Sonora. 



95. P. nudata Brandegee. Stems very numerous, much bran- 

 ched, erect from a fruticulose base, about 1.5 dm. high, green, sub- 

 striate, sparsely strigillose or subglabrous. Leaves bractlike, min- 

 ute, linear-lanceolate, acuminate, submucronulate, subsessile, 

 sparsely incurved-puberulous, 1-4.5 mm. long, 0.5 mm. wide. 

 Racemes terminating stems and branches, 4-6-flowered, straight, 

 2.8 cm. long or less. Flowers 4 mm. long, white. Upper sepal 

 ovate, acute, with rather strong midnerve and broad pale margin, 

 sparsely puberulous at tip and ciliolate, persistent, 2.7 mm. long ; the 



