LOASACEAE. 235 



Seeds prismatic, not separated by lamellae; petals 5; 



annuals. 1. Mentzelia. 



Seeds flat, winged, separated by horizontal lamellae; 



petals (in ours) 10. 2. Nuttallia. 



1. MENTZELIA L. 



Erect herbs with alternate entire lobed or pinnatifid 

 leaves, and terminal solitary or cymose flowers. Petals 5, 

 spreading, convolute in the bud, usually yellow. Styles 

 3, more or less united. Capsule dehiscent at the tip, 

 few-many-seeded. Seeds angled or prismatic, not sep- 

 arated by lamellae, roughened or striate. 



Filaments all filiform. 



Petals 5 mm. long or more. 



Calyx-lobes lanceolate, 3 mm. long. 1. M. davidsoniana. 



Calyx-lobes subulate, 4-6 mm, long. 2. M. affinis. 



Petals 2 mm, long; calyx-lobes 1 mm. long. 3. ikf. pinetorum. 

 Filaments, at least the outer, dilated or subu- 

 late. 

 Calyx-lobes 2 mm. long; petals 3 mm. long. 4. M. micrantha. 

 Calyx-lobes 4-10 mm. long; petals 8-16 mm. 



long. 5. M. gracilenta. 



1. M. davidsoniana Abrams (n. comb.). Erect, 2-3 dm. high; 

 leaves somewhat pinnatifid or nearly entire; calyx-lobes lanceolate, 

 3 mm. long; petals 8 mm. long; bracts conspicuous, mostly scarious, 

 concealing the capsules; seeds irregularly angled, only occasionally 

 grooved. (Acrolasia davidsoniana Abrams.) 



Open pine forests of the San Gabriel Mountains; Mt. Wilson, 

 Mt. Gleason. 



2. M. afl5.nis Greene. Stems stouter, 3-6 dm, high, simple and 

 leafy below, widely branching above; leaves lanceolate, deeply 

 sinuate-pinnate; flowers scattered, 12 mm, broad; calyx-lobes 

 attenuate, subulate, 4-6 mm, long; filaments all filiform; capsule 

 2.5 cm. long, almost linear, hispid with short stiff hairs; seeds pris- 

 matic, with grooved angles. 



Frequent in the upper portions of the chaparral belt and among 

 the pines. May-July. 



3. M. pinetorum (Heller) Abrams (n. comb.). Distinguished 

 from other southern California species by the very small flowers; 

 calyx-lobes 1 mm. long; petals 2 mm. long; capsule long attenuate. 

 (Acrolasia pinetorum Heller.) 



Mt. Wilson, according to Davidson; Rock Creek, Abrams & 

 McGregor. 



4. M. micrantha T. & G. Rather slender, 3-6 dm. high, simple 

 below, corymbosely and rather compactly dichotomous above; 

 leaves ovate, acute or acuminate, serrate or sinuate-toothed or 

 entire, 2.5-5 cm. long; flowers small, shorter than the floral leaves; 

 calyx-lobes 2 mm. long; petals oval, 3 mm. long; 5 outer stamens 

 with dilated filaments; capsule cylindric or nearly so, 6-12 mm. 



