LOASACEAE (STICK-LEAF FAMILY) 155 



W. Pubescence not retrorse; stipules scarious; flowers white or somewhat 

 yellowish, with purplish veins. U. V. ocellata 



RR. Stipules all entire, scarious. 

 W. Leaves rhombic-ovate with cuneate bases, except sometimes the basal. U. 



V. cuneata 



WW. Leaves cordate or reniform. 



X. Leaves cordate, acuminate. E. V. canadensis (CANADA VIOLET) 



XX. Leaves reniform, obtuse. W. V. flettii 



LOASACEAE (STICK-LEAF FAMILY) 



Herbs, erect often with hooked or stinging or viscid hairs. Leaves 

 alternate, pinnately veined, simple; stipules none. Flowers regular, 

 perfect, white or yellow. Calyx 5-lobed, persistent. Petals on 

 the calyx, 5-10. Stamens many, on the calyx. Ovary inferior, 

 i-celled; placentae 2-3, parietal. Capsule i -celled. Only the 

 following genus. 



MENTZELIA (STICK LEAF) 



Leaves mostly coarsely toothed or pinnatifid. Calyx tube cylindric to 

 obconic. Stamens 20-300. (Honor of C. Mentzel, a German botanist.) 



A. Biennials; flowers 2.5-6.3 cm. long; each placenta with 2 rows of ovules; capsule 



linear. 



B. Leaves lanceolate; petals 10. 



C. Outer petals less than 5 cm. long; plant 2-2.5 dm. high; some of the anther- 

 bearing filaments dilated. E. M. pumila 

 CC. Outer petals 5-6.2 cm. long; plant 6-9 dm. high; all of the filaments filiform. 

 E. M. laevicaulis 

 BB. Leaves linear; petals 5. E. M. brandegei 

 AA. Annual; flowers 0.3-1.6 cm. long; each placenta with i row of ovules; capsule 



oblong. 



D. Seed tuberculate, more or less grooved along the angles; leaves usually sinuate- 

 toothed. E. M. integrifolia 

 DD. Seed smooth or striate. 



E. Flowers not bracted; seed 0.7-1.4 mrrf. long. E. M. albicaulis 



EE. Flowers conspicuously bracted with wide-toothed bracts; seed almost 2 mm. 



long. E. M. congesta 



CACTACEAE (CACTUS FAMILY) 



Stems fleshy, spiny, the spines arising from cushions of minute 

 bristles. Leaves none or mere spines. Flowers perfect, regular, 

 showy. Calyx many-lobed or of distinct sepals. Petals many. 

 Stamens many. Ovary inferior, i-celled; placentae several, parietal. 

 Fruit mostly fleshy. Seeds many. 



A Stems not jointed, ovoid, not branched; " eyes" raised on tubercles. E. 

 (L. mamilla = a nipple; referring to the tubercles.) 



Mamillaria vivipara (BALL CACTUS) 

 AA. Stems jointed, branched; " eyes " not raised on tubercles. OPUNTIA (p. 156) 



