134 LOASACEAE 



rough. Leaves ovate to lanceolate, 15-25 mm. long, narrowed at base to a short petiole, usually 

 crenate-serrate, rough scabrous, gray-green, but shining ; flowers in bracted racemes ; bracts 

 long-acuminate ; pedicels short ; sepals subulate, membranous, 4—5 mm. long ; petals about 1 cm. 

 long, pale yellow; stamens but little exserted. 



Sandy or rocky soils. Lower Sonoran Zone; Mojave Desert, in Inyo and San Bernardino Counties, Cali- 

 fornia, to southern Nevada and northern Arizona. Type locality: southern Nevada. May-Aug. 



4. Petalonyx linearis Greene. Narrow-leaved Sandpaper Plant. Fig. 3279. 



Pctalonyx linearis Greene, Bull. Calif. Acad. 1 : 188. 1885. 



Bushy almost globose shrub, 15-30 cm. high, the branches light gray-green and scabrous. 

 Leaves oblong-lanceolate, 1-2.5 cm. long, short-petioled ; flowers in short capitate spikes that 

 elongate in fruit; bracts broadly ovate, obtuse at apex, cordate at base, entire, 5-7 mm. long, 

 densely pubescent ; petals white, 2 mm. long ; stamens but little exserted. 



Rocky places, Lower Sonoran Zone; eastern Mojave Desert, California, to western Arizona southward in 

 scattering localities to Lower California. Type locality: Cedros Island, Lower California. March-May. 



2. MENTZELIA [Phimier] L. Sp. PI. 516. 1753. 



Herbs or some tropical species trees or shrubs, clothed with variously barbed hairs, 

 the stems often white and shining-. Leaves alternate or sometimes opposite, usually 

 toothed or lobed. Flowers in terminal cymes, mostly yellow, subtended by bracts. Sepals 

 5, persistent or deciduous. Petals 5-10, imbricate, distinct or slightly united at base. 

 Stamens numerous, distinct or united in clusters opposite the petals; filaments filiform or 

 the outer petaloid ; anthers introrse. Hypanthium cylindric, ovoid or turbinate; style 3- 

 cleft ; ovary 1-celled; ovules few to many, anatropous. Fruit capsular, 3-5-valved. Seeds 

 smooth, striate or punctate; endosperm copious or sometimes scanty. [Name in honor of 

 C. Mentzel, German botanist, seventeenth century.] 



An American genus of about 60 species, most abundant in western North America. Type species, Mentselia 

 aspera L. 



Outer filaments, when dilated not toothed at the apex, or obscurely so in M. micrantha. 



Perennials or some winter annuals; placentae thick and fleshy or lamellate; seeds horizontal, in two or more 

 series. iBartonia) 



Seeds numerous (50-80), flat and broadly winged. 

 Petals 5. 



Petals lanceolate, acuminate, 1 . S-S cm. long. 



Petals 5-8 cm. long; capsule 3-4 cm. long. 1. M. laevicaulis. 



Petals 1.5-2 cm. long; capsule 1.5-2 cm. long. 2. M. Brandegei. 



Petals narrowly obovate, obtuse at the apex, 8-12 mm. long. 



Sepals narrowly lanceolate, 6-8 mm. long; bracts linear. 3. M. puberula. 



Sepals ovate-lanceolate, 9-11 mm. long; bracts lanceolate. 4. M. oreophila. 



Petals 10, the five inner being petaloid staminodia. 5. M. multiflora. 



Seeds few (7-12), ovoid, merely angled. 



Capsule erect in fruit. 6. M. Torreyi. 



Capsule on a strongly recurved pedicel. 7. M. reflexa. 



Annuals; petals 5; filaments all filiform or subulate, or the outer sometimes somewhat dilated; seeds pen- 

 dulous, in one series on the filiform placentae, minutely or conspicuously muriculate or tuberculate, 

 not winged. {Trachyphytum) 



Inflorescence not congested; bracts linear-lanceolate, not concealing the capsules. 

 Petals 15-40 mm. long; sepals 6-15 mm. long. 



Petals 20-40 mm. long, yellow with vermillion spot at base. 8. M. Lindleyi. 



Petals 15-25 mm. long, golden yellow throughout. 9. M. nitens. 



Petals 10 mm. or less in length. 



Seeds prismatic or cubical, grooved on 3 antjles, microscopically muriculate, appearing almost 

 smooth to the naked eye; filaments all filiform. 

 Leaves deeply pinnatifid; petals 5-7 mm. long. 10. M. affinis. 



Leaves usually entire, rarely toothed; petals 2-5 mm. long. 11. M. disperse. 



Seeds irregularly angled or somewhat prismatic, grooved only on 1 angle or not at all, con- 

 spicuously muriculate. 

 Sepals 2-3 mm. long; petals 2-6 mm. long. 



Petals 2—4 mm. long; seeds irregularly angled, not grooved on the angles. 



12. M. albicaulis. 



Petals 4-6 mm. long; seeds usually truncate at one end and grooved on 1 angle. 



13. M. Veatchiana. 



Sepals 5-6 mm. long; petals about 10 mm. long. 



Seeds somewhat prismatic and grooved on one angle; petals golden yellow throughout. 



14. M. gracilenta. 



Seeds irregularly angled, none of the angles grooved; petals with a copper-colored 

 spot at base. 15. M. pectinata. 



Inflorescence congested; bracts ovate, concealing the capsules. 



Bracts membranaceous; filaments filiform. 16. M. congesta. 



Bracts herbaceous; outer filaments dilated. 17. M. micrantha. 

 Outer filaments dilated and prolonged at apex into 2 blunt or cuspidate teeth with the anther in the sinus. 

 {Bicuspidaria) 



Bracts herbaceous, small, not concealing the flowers. 18. M. tricuspis. 



Bracts white, membranaceous, large and concealing the flowers. 19. M. involucrata. 



