OF ARTS AND SCIENCES. 117 



Thelypodium loxgifolium, Wats. Rich ravines, Mt. Orizaba, 

 10,000 ft., August (no. 250). The radical leaves are not present in 

 the type of this species, and later specimens in the Gray Herbarium 

 also lack them. The Mt. Orizaba specimens show them to be about 

 an inch long, narrowly spatulate, obtuse, sparingly toothed at the apex, 

 and very hispid with stellately branched hairs. 



Cerastium orithales, Schl. (Linnaea, XII. 209). Pine woods, 

 Mt. Orizaba, 13,000 ft., August (no. 236). A very handsome species, 

 well characterized by its simple stem and large flowers. 



Cerastium volcanicum, Schl. (Linnaea, XII. 208). Pine forests, 

 Mt. Orizaba, 11,000 ft., August (no. 213). The specimens referred to 

 this species have the petals but slightly cleft. The species is a prom- 

 inent element of the herbaceous flora at an altitude of 11,000 feet. 



Arenaria serpens, HBK. In pine woods, Mt. Orizaba, 13,000 

 ft., August (no. 234). As defined by Rohrbach (Linnaaa, XXXVII. 

 268), many forms are included under this species. The Mt. Orizaba 

 specimens, which seem best placed here, are closely related to A. 

 JBoui'ffCBi, Hemsl., but differ in the spatulate leaves and in the petals 

 only equalling or little exceeding the sepals. 



Drymaria filiformis. Glabrous throughout, 3-8 inches high : 

 stems erect or spreading from a slender rootstock, much branched, 

 filiform, somewhat rigid : leaves thickish, short-petioled, ovate to lan- 

 ceolate, narrowed at the base, 2-2^ lines in length, reduced to ovate 

 bracts above : stipules setaceous : flowers slender-pedicelled, disjiosed 

 in a diffuse cyme : sepals ovate, obtuse, herbaceous, scarious-margined, 

 with a dark tip or midnerve, somewhat carinate, a line long : petals 

 deeply cleft, shorter than the sepals : capsule globose, shortly stipitate, 

 many seeded. — Barren slopes, Mt. Orizaba, 9,000 ft., August (no. 

 267). Resembling D. anomala, Wats., in habit, foliage, and somewhat 

 in the inflorescence, but differing in the slender rootstocks, glabrous 

 obtuse sepals, and much longer-pedicelled flowers at the nodes of the 

 branches. 



Astragalus (Mollissimi) Orizab.e. Stem decumbent, branched, 

 clothed with a short white tomentum, a foot or less high : leaves 

 including petiole 4-6 inches long; leaflets 14-17 pairs, petiolulate, 

 oblong-lanceolate, obtuse or acutish, somewhat cuneate at the base, 5-8 

 lines in length, white sericeous-pubescent : stipules narrowly deltoid, 

 acuminate, 2-2 i^ lines long ; peduncles shorter than the leaves : 

 racemes oblong, lJ-2^ inches in length: bracts linear-lanceolate. If 

 lines long, exceeding the pedicels : calyx sericeous-pubescent, 3-4 lines 

 in length, the linear acuminate teeth three fourths as long as the 



