LOASACEAE (LOASA FAMILY) 325 



coming white and polished, nearly glabrous: leaves lanceolate to linear, from 

 nearly entire to deeply sinuate-pinnatifid, sessile or nearly so, scabrous: 

 flowers small, solitary or in loose clusters, not bracteolate: petals 5, yellow, 

 obovute, about 4 mm. long, scarcely longer than the subulate-lanceolate 

 calyx-segments: filaments 20-40, subulate-filiform: capsule linear-clavate : 

 seeds numerous, irregularly angled with obtuse margins, rather strongly 

 tuberculate. (M. Tweedyi and M. tenerrima Rydb. Mem. N. Y. Bot. Card. 

 1: 271. 1900; M. ctenophora Rydb. Bull. Torr. Bot. Club 28: 33. 1901; 

 M. gracilis Rydb. 1. c. 566. 1904.) Frequent; on slopes and dry banks, 

 often in partial shade; throughout our range and far westward. 



4. Mentzelia dispersa (Wats.) Proc. Am. Acad. 11: 137. 1876. A slender 

 annual, usually about 3 dm. high: leaves narrowly lanceolate, sinuate-toothed 

 or sometimes entire, rarely pinnatifid, the uppermost often ovate: flowers 

 small, mostly approximate near the ends of the branches: calyx-lobes 2 mm. 

 long, little snorter than the five spatulate or obovate petals: filaments not, di- 

 lated: capsule narrowly linear-clavate, 15-25 mm. long: seeds very often in 

 a single row, angular and somewhat rhombohedral, more or less grooved upon 

 the angles, very nearly smooth, 1 mm. long. Colorado to Montana and west 

 to Washington. 



5. Mentzelia compacta A. Nels. Bull. Torr. Bot. Club 25: 275. 1898. 

 Annual, 2-2.5 dm. high, numerously and compactly branched: stems whitish, 

 pubescent, somewhat brittle: leaves numerous, sessile, entire, obtuse, from 

 broadly linear at base to almost oval at summit, generally ovate-oblong, 

 2-3 cm. long, rough-hirsute, more coarsely and sparsely so above: flowers 

 yellow, small, numerous, in compact cymes at the ends of the branches, ses- 

 sile, about 3 mm. broad: calyx-lobes lanceolate-ovate, shorter than the corolla: 

 petals obovate, about 4 mm. long: stamens 15, anthers small, subspherical : 

 capsule linear-clavate, 10-13 mm. long, 10-12-seeded: seeds in one compact 

 row, smooth, longitudinally groove-angled, in form from frustra of triangular 

 prisms to rhomboidal cuboids, faces about 1 mm. long. Wyoming and 

 northward. 



6. Mentzelia decapetala (Pursh) Urban and Gilg. in Engl. & Prantl Nat. 

 Pfl. Fam. 3: 111. 1894. Roughish-pubescent, stout, seldom over 6 dm. high: 

 leaves oval, lanceolate or oblong, acute or acuminate, sinuate-pinnatifid, 

 5-15 cm. long, the upper sessile, the lower petioled: flowers mostly solitary, 

 terminal: petals 10, about twice as long as the lanceolate calyx-lobes: fila- 

 ments all filiform, very numerous (200-300): capsule oblong, 3-5 cm. long: 

 seeds numerous, margined, not winged. M. ornata. From Montana to 

 Xew Mexico and Texas. 



7. Mentzelia nuda (Pursh) T. & G. Fl. X. A. 1: 535. 1840. Rough with 

 minute pubescence, slender, 3-15 dm. high, the stems light-colored: leaves 

 lanceolate or oblong-lanceolate, acute, usually sharply and deeply dentate, 

 or the upper pinnatifid, 2-8 cm. long: petals 10, about twice as long as the 

 lanceolate calyx-lobes: calyx-tube usually not bracteolate: stamens 100 or 

 more, the outer ones somewhat petaloid: capsule oblong, 1.5-2.5 cm. long, 

 about 6 mm. thick: seeds numerous, wing-margined. (M. stricta Osterh. 

 Bull. Torr. Bot. Club 29: 174. 1902; M. Rusbyi Wooton, Bull. Torr. Bot. 

 Club 25: 261. 1898.) Plains; Montana to New Mexico. 



8. Mentzelia chrysantha Engelm. Brand. Bull. U. S. Surv. Terr. 2: 237. 

 1876. Stems 3-6 dm. high, branching: leaves ovate-lanceolate, the lower 

 narrowed towards the base: flowers subsessile: petals 12-18 mm. long, acute, 

 often fewer than 10, the innermost smaller and antheriferous: seeds narrowly 

 margined but not winged. Southern Wyoming to Colorado and Utah. 



9. Mentzelia multiflora (Nutt.) Gray, Pl.Fendl.48. 1848. Stems scabrous, 

 branching freely, 2-4 dm. high: leaves generally deeply sinuate-pinnatifid, 

 attenuate below: petals yellow, abruptly pointed, 12-20 mm. long, exceed- 

 ing the subulate calyx-segments: outer filaments noticeably dilated: capsule 

 short, obconic with broad summit: seeds few, broadly winged. (M. laciniata 

 Rydb. 1. c. 31 : 566.) Colorado to New Mexico. 



9a. Mentzelia multiflora densa (Greene) A. Nels. Freely branched, short- 



