HALORAGE.E. (WATHR-MILFOIL FAMILY.) 99 



* * * Flowers perfect, secund upon the branches of a forked ci/ine, mostli) yellow 

 or yellowish: leaces venj Jleshij, entire. 

 H- Leaves narrowed toward the base, ohtiise. 

 . 3. S. debile, Watson. Stems weak, 2 to 4 iuclies higli, from very sleixler 

 running rootstofks: leaves rounded or obovate : flowers on rather long pedi- 

 cels, in small cymes. — Bot. King's Exp. 102. In the Wasatch and lintas: 

 also mountains of Nevada and N. California. 



-t- H- Leaves broadest at base, acute. 



4. S. Stenopetalum, Pursh. Stems 3 to 6 inches high, simple or some- 

 times branched : leaves narrowly lanceolate : flowers briijld i/ellow, uearh/ sessile. 

 — Torr. & Gray, Fl. i. 560. Very common on both sides of tlie mountains 

 from Colorado to Montana and into Oregon. 



5. S. Douglasii, Hook. Stems 3 to 4 inches high, branching at ba.se, 

 from a stout proliferous rootstock : leaves lanceolate or the lowermost linear- 

 subulate, membranaceous when dry: flowers sometimes polygamous, scs.sile: 

 follicles at len<itli divaricateli/ spreading from their united bases. — National Park, 

 W. Montana, Oregon, and California. 



Order 29. HALORAGEiE. (Water-Milfoil Family.) 



Aquatic herbs, with mcouspicuons and often apetalous flowers sessile 

 in the axil of leaves or bracts, calyx adnate to the ovary iu fertile ones, 

 tlie fruit indehiscent and nut-like. 



1. Hippuris. Leaves linear, in whorls of 8 or 12. Flowers perfect. Caly.x entire. Petals 

 none. Stamen and cell of the ovary one. 



2 Myriopliyllum. Immersed leaves pinnately dissected. Flowers monoecious or polyga- 

 mous. Parts of the flower in fours. 



1. HIPPURIS, L. Mare's Tail. 



Calyx-tube globular. — Smooth : with erect simple leafy stems : leaves 

 entire : flowers solitary. 



1. H. vulgaris, L. Stems a foot or two high : leaves usunlly a half to an 

 inch long, but often much longer, especially the submerged ones : calyx hardly 

 a half-line long. — In shallow ponds throuuhout the northern part of the con- 

 tinent, and southward in the Rocky ^lountains to New Mexico. 



2. MYRIOPHYLLUM, L. Water-Mi lfoil. 



Limb of the calyx 4-lobed in the sterile flowers, wanting or minutely toothed 

 in the others. Petals 2 to 4, minute or wanting in the pistihate flowers. 

 Stamens 8 (iu ours). Ovary 4-celled : stigmas recurved and plumose. — 

 Smooth leafy herbs : leaves whorled in threes or fours : upper flowers usually 

 staminate, the lower pistillate, and the intermediate ones perfect. 



1. M. spicatum, L. Leaves all pinnately parted and capillary, errrpt 

 the floral ones or bracts; these ovate, entire or toothed, and chief'/ shorter than the 

 flowers, which thus form an interrupted spike. — In the Atlantic States and 

 across the continent. 



