VOL. II.] 



LOASA FAMILY. 



459 



3. Mentzelia albicaulis Dougl. White-stemmed Mentzelia. 



Mentzelia albicaulis Dougl. ; Hook. Fl. Bor. Am. 



i: 222. As synonym. 1833. 

 Bartonia albicaulis Dougl.; Hook. Fl. Bor. Am. 



1:222. 1833. 



Stem nearly white, erect or ascending, slen- 

 der, branched, shining, nearly smooth, or 

 roughish above, 6 x -2 high. Leaves sessile, 

 mostly lanceolate in outline, sinuate-pinnatifid, 

 sinuate-lobed, or the upper and lower some- 

 times entire, rough with short stiff hairs, if-$ r 

 long; flowers yellow, few together at the ends 

 of the branches, or also axillary, 6 // -io // broad, 

 short-pedicelled or sessile; calyx-lobes linear- 

 lanceolate, about 2 /x long; capsule linear, i' 

 long or less, many-seeded; seeds angled, 

 tuberculate, wingless. 



Western Nebraska to British Columbia, Califor- 

 nia and New Mexico, the more eastern plant with 

 less pinnatifid leaves than the western, and perhaps 

 different specifically. May-July. 



(Fig. 2519.) 



4. Mentzelia decapetala (Pursh) Urban 

 & Gilg. Showy Mentzelia. (Fig. 2520.) 



Bartonia decapetala Pursh, in Bot. Mag. pi. 1487. 1812. 

 Bartonia ornata Pursh, Fl. Am. Sept. 327. 1814. 

 Mentzelia ornata T. & G. Fl. N. A. i: 534. 1840. 

 Mentzelia decapetala Urban & Gilg, in Engl. & Prantl, 

 Nat. Pfl. Fam. 3: Abt. 6a, in. 1894. 



Roughish-pubcscent, stout, seldom over 2 high. 

 Leaves oval, lanceolate or oblong, acute or acumi- 

 nate at the apex, sinuate-pinnatifid, 2 / -6 / long, 

 the upper sessile, the lower petioled ; flowers mostly 

 solitary and terminal, yellowish white, 3'-$' broad, 

 opening in the evening; petals 10, about twice as 

 long as the lanceolate calyx-lobes; calyx-tube usu- 

 ally bracted; filaments all filiform, very numerous 

 (200-300); capsule oblong, i>^ / -2 / long, 5 // -6 // 

 thick; seeds numerous, margined, not winged. 



Plains, Dakota and Montana to Nebraska and Texas. 

 June-Sept. 



5. Mentzelia laevicaulis (Dougl.) 



T. & G. Smooth-stemmed Mentzelia. 



(Fig. 2521.) 



Bartonia laevicaulis Dougl.; Hook. Fl. Bor. Am. 



i: 221. 1833. 

 Mentzelia laevicaulis^. & G. Fl. N. A. i: 535. 1840. 



Stout, 2-4 high, minutely pubescent, or the 

 stems at length glabrate and whitish. Leaves 

 sessile, lanceolate or ovate-lanceolate, sinuate- 

 pinnatifid, acute or acuminate at the apex, I'jf 

 long; flowers mostly solitary and terminal, 

 bright yellow, $'-4,' broad, opening in sunshine; 

 calyx-tube bractless; petals 5, or with 5 addi- 

 tional narrower inner ones, 2-3 times as long 

 as the calyx-lobes; stamens very numerous; 

 capsule oblong, about \' long, 4" in diameter; 

 seeds numerous, winged, minutely tuberculate. 



Plains and dry soil, Nebraska, Montana and 

 Wyoming to Oregon, south to Utah and California. 

 June-July. 



