5 6b 



LOASACEAE. 



VOL. II 



(rarely 2-3-celled), with 2 or 3 parietal placentae; style filiform, entire or 2-3- 

 lobed ; ovules anatropous Capsule usually i-celled, crowned with the calyx-limb. 

 Seeds mostly numerous ; endosperm scanty. 



About 20 genera and 250 species, all but i natives of America. 



Seeds angled or prismatic, not separated by lamellae; mostly annuals. 

 Seeds flat, winged, separated by horizontal lamellae ; perennials. 



1. Mentzelia. 



2. Nuttailia. 



i. MENTZELIA L. Sp. PI. 516. 1753. 



Erect herbs, mostly annuals, with alternate entire lobed 01 pinnatifid leaves, and terminal 

 solitary or cymose flowers. Calyx-tube cylindric, linear or club-shaped, its limb generally 

 5-lobed. Petals 5, spreading, convolute in the bud, deciduous Stamens 20-100. Ovary 

 i-celled ; styles 3, more or less united ; stigmas small, obtuse. Capsule dehiscent at the sum- 

 mit, few-many-seeded. Seeds mostly prismatic, not separated by horizontal lamellae, rough- 

 ened or striate. [Named in honor of C Mentzel, a German botanist, died 1701.] 



About 35 species, natives of America. Besides the following, some 20 others occur in the west- 

 ern parts of North America. Type species : Mentselia aspera L. 



Leaves sessile ; stem little rough ; calyx-lobes 2" long. 



Leaves, at least the lower, petioled ; stem very rough ; calyx-lobes 3" long. 



1. M. oligosperma. 



2. M albicaulis. 



i. Mentzelia oligosperma Nutt. Few- seeded Mentzelia. Fig. 2976. 



Mentselia oligosperma Nutt. in Bot. Mag. pi. 1760. 



1815. 

 Mentzelia aurea Nutt. Gen. i : 300. 1818 



Rough and viscid-pubescent, i-3 high. 

 Leaves ovate or oval, coarsely dentate or sinu- 

 ate, acute or obtusish at the apex, i'-3' long, 

 the upper rounded or truncate at the base and 

 sessile, the lower narrowed at the base and 

 usually petioled; flowers yellow, s"-io" broad, 

 axillary or somewhat cymose, opening in sun- 

 shine ; petals 5, oblong-cuneate, acute, about 

 twice as long as the linear-lanceolate calyx- 

 lobes; filaments 20-30, all filiform; capsule 

 linear, 6"-8" long, few-seeded; calyx-lobes about 

 3" long; seeds oblong, wingless. 



Prairies and plains, Illinois to South Dakota, 

 Kansas, Colorado, Louisiana, Texas and Mexico. 

 May-July. 



2. Mentzelia albicaulis Dougl. White- 

 stemmed Mentzelia. Fig. 2977. 



Mentzelia albicaulis Dougl. ; T. & G Fl. N, A. 1 : 534. 



1840. 

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



222. 1833. 



Stem nearly white, erect or ascending, slender, 

 branched, shining, nearly smooth, or roughish 

 above, 6'-2 high. Leaves sessile, mostly lanceo- 

 late in outline, sinuate-pinnatifid, sinuate-lobed, 

 or the upper and lower sometimes entire, rough 

 with shoft stiff hairs, i'-3' 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" long; fila- 

 ments separate; capsule linear, i' long or less, 

 many-seeded ; seeds angled, tuberculate, wingless. 



Western Nebraska to British Columbia, California 

 and New Mexico. May-July. 



2. NUTTALLIA Raf. Am. Month. Mag. 

 2: 175. 1817. 



[BARTONIA Pursh ; Sims. Bot. Mag. pi. 1487. 1812. Not. Muhl. 1801.] 



Perennial herbs, with alternate lobed or pinnatifid leaves and terminal, cymose or soli- 

 tary, large and showy flowers. Calyx-tube mostly obconic, the limb 5-lobed. Petals 5, in 



