WATERLEAF FAMILY 191 



Capsules ovoid, acute; ovules 12-40; stamens slightly if at all exceeding the 



corolla. IV. LiNEARES. 



Plant perennial, cespitose; inflorescence spicate-thyrsiform. V. Serice.\e. 

 Stamens shorter than the corolla; plant low and diffuse; annuals. 



Seeds reticulate or favose-pitted, not transversely rugose; leaves long-petioled, entire 



or crenately lobed. VI. Pulchellae. 



Seeds strongly corrugated transversely; leaves pinnately divided. 



VII. BiCOLORES. 



I. Heterophyllae. 

 Plant perennial, or at least biennial. 

 Plant densely canescent. 



Calyx-lobes linear or linear-oblong; inid veins inconspicuous; corolla pink or pale 



iilac, about 6 mm. long. I. P. leucophylla. 



Calyx-lobes narrowly linear; niidveins, at least in fruit, very strong; corolla white. 

 4-5 mm. long. 2. P. Burkei. 



Plant not densely canescent. 



Pubescence of the leaves of two kinds, long hirsute hairs and a fine pilose or tomen- 

 tose pubescence. 

 Calyx almost as long as the white corolla, its lobes narrowly linear, acute. 



with a strong midrib. 3. P. nervosa. 



Calyx much shorter than the corolla; niidveins faint. 



Stem erect; calyx from two-tliirds to ttu'ee-foiu'tlis as long as the corolla. 

 Plant biennial or short-lived perennial; corolla pink or lilac. 



4. P. biennis. 

 Plant a cespitose perennial; corolla usually wliite. 



b. P. heterophylla. 

 Stem ascending, slender; inflorescence open; calyx about half as long as 

 the pilose purplish corolla. 6. P. alpina. 



Pubescence of the leaves hirsute only; calyx-lobes narrowly linear; midrib weak; 

 corolla white. 7. P. leptosepala. 



Plant annual. 



Corolla 5-6 mm. long; ovules 4. 8. P. humilis. 



Corolla 8-10 mm. long; ovules 12-16. 24. P. linearis. 



II. Gl.\ndulosae. 

 CoroUa-iobes entire or merely sinuate-crenate. 



Leaves sinuate-crenate to lobed half ways to the midrib. 



Corolla narrowly campanulate; plant simple, strict, densely hirsute. 



9. P. Palrneri. 

 Corolla open-campanulate; plant branched, scarcely at all hirsute, very glandular. 

 Stem-leaves suborbicular, subcordate at the base. 10. P. orbicularis. 



Stem-leaves not suborbicular. 



Stem-leaves ovate, oval, or elliptic in outline. 11. P. integrifolia. 



Stem-leaves oblong in outline. 12. P. corrugata. 



Leaves pinnately divided to the midrib. 



Leaves densely hirsute or pilose, only slightly glandular; plant low, 1-2.5 dm. 

 high, often naked above. 

 Leaves oblanceolate or spatulate in outline; calyx decidedly liirsute-hispid ; 



stem and petioles glandular. i:3. P. crenulata. 



Leaves oblong or linear in outline; calyx scarcely hispid, but densely glandular: 

 stem and petioles wliite- villous. 14. P. deserta. 



Leaves hirsute only on the veins, short-pubescent and very viscid; plant stouter. 

 2^ dm. high, branched. 

 Terminal divisions of the leaves large and obovate in outline. 



15. P. splcndcns. 

 Terminal divisions of the leaves not much enlarged, ovate, lanceolate or oblong 

 in outline. 16. P. glandulosa. 



Corolla-lobes distinctly dentate or erose. 



Corolla white; stamens about twice as long as the corolla. 17. P. alba. 



Corolla purplish or pink. 



Stamens slightly e.^LCeeding the corolla; corolla-lobes erose. 18. P. neomexicana. 

 Stamens included; corolla-lobes dentate. 19. P. denticulaia. 



III. Ramosisslmae. 



Leaves i)innatifld or bipinnatifld. 



Calyx-lobes oblanceolate; segments of the leaves broad, obovate or oblong; plant 



diffusely branched. 20. P. raniosissima. 



Calyx-lobes linear; segments of the leaves small, oblong; plant simple. 



21. P. hispida. 

 Leaves round-lobed and coarsely crenate. 22. P. Rattani. 



IV. LiNEARES. 



Leaves pinnately divided with numerous divisions, which are often toothed. 



23. P. Franklinii. 

 Leaves entire or with 3-5 entire divisions. . 24. P. linearis. 



V. Sehiceae. 

 Stamens only slightly exceeding the corolla. 25. P. idahoensis. 



Stamens at least twice as long as the corolla. 



Leaves divided half ways to the midrib; stamens twice as long as the corolla. 



26. P. Lyallii. 



