324 LOASACEAE (LOASA FAMILY) 



4-12 mm. long, articulated, bibracteolate: flowers small: capsules glabrous: 

 seeds turning black. lonidium linear e Torr.: Calceolaria, verticillata (Ort.) 

 Kuntz, Rev. Gen. PL 41. 1891. 



77. LOASACEAE Reichenb. LOASA FAMILY 



Herbaceous plants with either stinging or jointed and rough-barbed hairs, 

 no stipules, calyx- tube adnate to a 1 -celled ovary, parietal placentae, and a 

 single style. Stamens usually very numerous, some of the outer occasionally 

 petaloid. Flowers perfect, often showy. 



^. 



MENTZELIA L.* 



Erect, the stems becoming white and shining. Leaves alternate, mostly 

 coarsely toothed or pinnatifid. Flowers cymose or solitary, orange or golden- 

 yellow to white. Calyx-tube cylindrical or turbinate; the limb 5-lobed. 

 Petals 5 or 10. Stamens inserted below the petals on the throat of the calyx. 

 Ovary truncate at the summit; style 3-cleft, the lobes often twisted. Capsule 

 opening usually irregularly at the apex. 



Petals 5, small; filaments all filiform; seeds not winged. 



Leaves petioled . . . . . . . . . .1. M. oligosperma. 



Leaves sessile. 

 Seeds tuberculate. 



Leaves broad, merely toothed . . . . . 2. M. latifolia. 



Leaves narrow, entire to sinuate-pinnatifid . . . 3. M. albicaulis. 



Seeds smooth or striate. 



Stems slender and sparsely branched . . . . 4. M. dispersa. 



Stems low, numerously and compactly branched . . 5. M. compacta. 



Petals 5 or 10, large; filaments often dilatedrpetaloid. 

 Flowers white or merely yellowish. 



Seeds margined but not winged 6. M. decapetala. 



Seeds conspicuously winged . . . . . . 7. M. nuda. 



Flowers yellow. 



Seeds margined but not winged. 



Stems smooth . . . . . . . . 8. M. chrysantha. 



Stems puberulent . . . . . . . . . 9. M. multiflora. 



Seeds evidently winged. 



Petals 10, large; filaments filiform. 



Seeds tuberculate 10. M. laevicaulis. 



Seeds smooth 11. M. speciosa. 



Petals 5, smaller; some of the filaments dilated and an- 



theriferous ......... 12. M. pumila. 



1. Mentzelia oligosperma Nutt. T. & G. Fl. N. A. 1: 533. 1840. Rough 

 with multibarbate hairs, dichotomously branched, brittle, 2-8 dm. high: 

 leaves ovate-lanceolate, cuneate at the base, incisely toothed or somewhat 

 lobed and angled, 3-7 cm. long, short-petioled : petals 5, cuneate-oblong, 

 cuspidate, entire, a little longer than the 20 or more stamens, golden-yellow, 

 expanding in sunshine, evanescent: filaments all linear: capsule narrow, 

 6-12-seeded: seeds oblong, irregular, not winged. (M. Nelsonii Greene, 

 Erythea 3: 70. 1895.) Extending into our range from the Mississippi valley. 



2. Mentzelia latifolia (Rydb.) A. Nels. Stout annual, 3-5 dm. high, 

 branched: leaves sessile, ovate or ovate-lanceolate, coarsely toothed or entire, 

 5-10 cm. long, 2-3 cm. wide: sepals lanceolate, 2.5-3 mm. long: petals obovate- 

 spatulate, about 5 mm. long: capsule linear, cylindric, 2.5-3 cm. long, about 

 2.5 mm. thick, sessile: seeds prismatic, muriculate. (Acrolasia latifolia Rydb. 

 Bull. Torr. Bot. Club 31: 567. 1904.) Mountains of Colorado. 



3. Mentzelia albicaulis Dougl. Hook. Fl. Bor. Am. 1: 222. 1833. Low, 

 nearly simple or branching from the base, 1-3 dm. high: stem very pale, be- 



* This genus has been the subject of much discussion in recent years. Naturally readily 

 separated into two sections, the large-flowered forms were erected into a genus under the 

 name Hasperaster. This group has since been successively referred to Touterea and to 

 NuttaUia, while the other or small-flowered group has been called Acrolasia. 



