275 Rydberg: Studies on the Rocky Mountain Flora 



Arenaria confusa sp. nov. 



A slender diffuse plant with cespitose, perennial, but not ligneous 

 base. Stems slender, branched, 4—6 dm. long, finely puberulent ■ 

 leaves opposite, linear-lanceolate, pointed, with a strong midrib, 

 puberulent, 1—2 cm. long : pedicels in fruit divergent, about i cm. 

 long, slightly bent under the calyx : sepals linear-lanceolate, acumi- 

 nate, scarious-margined, not tuberculate-punctate, about 3 mm. 

 long : petals about three fourths as long as the sepals : capsule 

 broadly ovoid, about 4 mm. long. 



This species is related to A. lanuginosa and A. saxosa, and some- 

 what intermediate between the two. In habit it resembles most 

 the former, but does not have the subverticillate or fascicled leaves ; 

 the sepals are narrowly lanceolate instead of ovate and not tuber- 

 culate-punctate, the stem is not retrorsely pubescent as in that 

 species and the petals are larger. In all specimens of A. lanuginosa 

 seen by me the petals are either lacking or not more than half as 

 long as the sepals. A. saxosa is subligneous at the base, has low 

 stems, short leaves, mostly less than i cm. long and sepals even 

 in flower 4-5 mm. long. Dr. B. L. Robinson, in the Synoptical 

 Flora, remarks under A. alsinoidcs (^A. lanuginosa) : " A more 

 western form, represented from New Mexico by Fendler's 58 and 

 62 and Wright's 864, has slightly firmer stems, more numerous 

 subpaniculate flowers, and leaves less narrowed at the base. In 

 all these respects it shows a transition to the following." I have 

 not seen the numbers of Fendler's collection cited ; but Wright's 

 864 as represented in Columbia University Herbarium belongs to 

 A. confusa. On the sheet of Rusby's 38, cited below, found in 

 the Columbia University herbarium. Dr. Robinson has written in 

 pencil : " Apparently this is merely a lax form of A. saxosa Gray. 

 The earliest leaves are crowded, the upper internodes much 

 elongated, and later flowers are always smaller. (B. L. R.)" 

 Wilcox's plant cited below was also determined by Dr. Robin- 

 son as A. saxosa. Both of these agree perfectly, however, with 

 Wright's specimens ; but neither with our material of A. lanuginosa 

 from the Southern States and Mexico, nor with the type of A. 

 saxosa. A. confusa grows in caiions at an altitude of 2000—3 5^0 ^n. 



New Mexico : White Mountains, 1897, E. 0. Wooton, 2^j 

 (type); 185 1, C. Wright, 86-/. ; Burrow- Mountains, 1880,//. H. 

 Rusby, j8. 



