WATERLEAF FAMILY 191 



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

 corolla. IV. Lineahes. 



Plant perennial, cespitose; inflorescence spicate-thyrsiform. V. Sericeae. 

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



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



or crenately lobed. VI. Polchellae. 



Seeds strongly corrugated transversely; leaves pinnately divided. 



VII. BiCOLOHES. 



I. Heterophyllae. 

 Plant perennial, or at least biennial. 

 Plant densely canescent. 



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



lilac, about 6 mm. long. 1. P. leucophylla. 



Calyx-lobes narrowly linear; midveins, 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 flue 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; midveins faint. 



Stem erect; calyx from two-thirds to three-fourths as long as the corolla. 

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



4. P. biennis. 

 Plant a cespitose perennial; corolla usuaUy white. 



5. P. heterophylla. 

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



the pUose 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. Glandulosae. 

 CoroUa-lobes entire or merely sinuate-crenate. 



Leaves sinuate-crenate to lobed halfways to the midrib. 



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



9. P. Palmeri. 

 CoroUa 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. iniegrifolia. 



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 hirsute-hispid; 



stem and petioles glandular. 13. P. crenulata. 



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

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



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

 2—4 dm. hl^h, branched. 

 Terminal divisions of the leaves large and obovate In outUne. 



15. P. splendens. 

 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 coroUa. 17. P. alba. 

 Corolla purplish or pink. 



Stamens slightly exceeding the corolla; coroUa-lobes erose. 18. P. neomezicana. 

 Stamens included; coroUa-lobes dentate. 19. P. denticulata. 



III. Ramosissimae. 

 Leaves pinnatifld or bipinnatifld. 



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



diffusely branched. 20. P. ramosissima. 



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



21. P. hispida. 

 Leaves roimd-lobed and coarsely crenate. 22. P. Battani. 



IV. LlNEARES. 



Leaves pinnately divided with numero<is divisions, which are often toothed. 



23. P. Franklinii. 

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



V. Sericeae. 

 Stamens only sUghtly exceeding the coroUa. 25. P. idahoensis. 



Stamens at least twice as long as the corolla. 



Leaves divided halfways to the midrib ; stamens twice as long as the coroUa. 



26. P. Lyallii. 



