MEMOIRS FEOM THE DEPARTMENT OF BOTANY OF COLUMBIA UNIVERSITY 123 



§5. HIRSUTAE. 



Resembling somewhat the preceding group, bui with more numerous and often dis- 

 sected leaflets, broader filaments, and lower stipules which are once or twice pinnately dis- 

 sected into linear or filiform hairy segments. 



Cyme fastigiately corymbose. 



Leaves oblong-cuneate, 2-6-toothed at the apex. 



Plant silky ; leaflets about i pairs. [22. H. congesta.] 



Plant hirsute ; leaflets 4-10 pairs. 23. H. hirsuta. 



Leaflets divided to near the base into linear segments. 



Stem more or less glandular ; segments linear, acute, 1-2 mm. wide. 24. H. daueifolia. 



Stem silky-villous, not glandular ; segments narrowly linear, less than 1 mm. wide. 



25. H. earuifolia. 

 Cyme open and lax. 



Leaflets cuneate, cleft half their length at the apex into oblong-acute segments. 



26. H. laxiflora. 

 Leaflets divided to the base into oblong or oval segments. 27. H. Howellii. 



§6. SERICATAE. 



This group contains a single species somewhat resembling the last one of the pre- 

 ceding group, but the stipules are not dissected. Cyme lax and few-flowered. Leaflets 

 densely white-silky, crowded as in most Ivesiac. 

 One species. 28. H. sericata. 



Subgenus Horkeliella. 



§7. PURPURASCENTES. 



Stem slender, erect and strict, cyme open. Leaflets very numerous, over 20 pairs. 

 Hypanthium campanulate ;. sepals reflexed in anthesis. Petals strap-shaped. Stamens 

 20, in three series, the inner (antipetalous) ones the shortest; fllaments all lanceolate. 

 Pistils rather numerous. 



In the numerous leaflets and the 20 stamens the group approaches Ivcsia, but the 

 floral structures are otherwise exactly as in Horkelia, especially the Galifornicae group. 



Plant 3-4 dm. high, smooth ; leaflets 5-8 mm. long. 29. H. pinetorum. 



Plant 1-2 dm. high, densely pubescent ; leaflets 2-3 mm. long. 30. H. pirrpurascens. 



