MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 27 1 



LOASACEAE. 



Mentzelia integrifolia (Wats.); Mentzclia albican I is intcgrifolia 



Wats. King's Exp. 5: 114. 187 1 ; Mentzelia dispersa Wats. 



Proc. Am. Acad, ii : 115. 1876 [Man. R. Isl. 107; Bot. Cal. 



I: 236]. 



Hillsides, up to an altitude of 2500 m. 



Montana: Spanish Basin, June 24, 1897, Rydberg & Bessey^ 



4544; Bozeman, 1887, Tweedy, iji ' 1884; Columbia Falls, J/r5. 



y. y. Kennedy, J2 ; Prickly Pear Canon, 1887, 7?. S. Williams, 



68 J ; Mystic Lake, 1883, Canby, ijg; Shinberger's Canon, 1880, 



Watson; Ross' Hole, 1880, Watson. 



Yellowstone Park: Cache Creek, 1885, Tzveedy, 4jJ. 



* Mentzelia tenerrima. 



Stem very slender, only 1-2 mm. in diameter, ascending, branched, 

 straw-color, pilose, in age glabrous, 4-5 dm. high ; root annual ; 

 leaves linear-lanceolate, 2-3 cm. long, pilose, entire ; flowers very 

 small, subtended by one or two linear bracts; sepals linear-lanceo- 

 late, I mm. long; petals narrow, 2-3 mm. long, lemon-yellow; cap- 

 sule linear, 15 mm. long and 2-3 mm. in diameter; seeds i mm. 

 long, sharply angled and finely pitted under a strong lens. 



Belongs to the M. integrifolia group, but is much more slender 

 than an}^ described species. It was found on a dry hillside, together 

 with Chenofodiuni atrovircns, at the base of a few trees of the 

 Douglas Spruce, at an altitude of 2500 m. 



Montana: Foot of Electric Peak, August 18, 1897, Rydberg & 

 JBessey, 4^42. 



* Mentzelia Tweedyi. 



Root annual ; stem very slender as in the last species, erect, about 

 3 dm. high, 1-2 mm. in diameter, somewhat pilose when young, 

 straw-colored ; leaves linear in outline, 2-5 cm. long, pinnately lobed 

 with distant oblong lobes, or the upper ones almost entire ; flowers 

 very small, subtended by small linear bracts: petals 5, oblanceolate, 

 light yellow, 3-4 mm. long; sepals subulate, i mm. long; capsule 

 linear-clavate, 15 mm. long and 2-3 mm. in diameter; seeds 

 round-angled, muricate. 



Resembles closely the preceding, differing only in the seeds and 

 the leaves. It stands in the same relation to J/, albicaulis as the pre- 

 ceding does to M. integrifolia. It was found under pine trees, at 

 an altitude of 1800 m. 



Montana: Trail Creek, Park Co., 1887, Tzuecdy, 132. 



