RANUNCULACEAE. 155 



flowers white, in corymbs; sepals 3-5, broad, concave; petals 

 none; stamens numerous; pistils numerous, 1-ovuled; akenes 

 capitate, sharply-angled, inflated; styles minute. 



Trautvetteria grandis Nutt. Stems 30-50 cm. tall, glabrous or nearly so; 

 leaves broader than long, 8-30 cm. across, 5-9-cleft, the lobes oblong or ob- 

 ovate, acute, incisely lobed and toothed; akenes smooth, ovate, three-angled, 

 tipped with a slender recurved beak. 



In mountain meadows and along mountain streams. 



195. MYOSURUS. MOUSE TAIL. 



Very small annual herbs; leaves entire, linear or at first spatu- 

 late, in a basal tuft; scapes simple, 1-flowered; sepals 5, spurred 

 at the base; petals 5, greenish-yellow, with long nectariferous 

 claws, or none; stamens 520; pistils numerous, borne on a 

 central axis, the receptacle, which becomes greatly elongated in 

 fruit; ovule 1. 



Myosurus major Greene. Scapes several-many, 8-15 cm. high; fruiting 

 spikes 2-4 cm. long, rather stout; akenes with a short straight beak. 

 Vancouver Island to California. 



196. BATRACHIUM. WATER BUTTERCUP. 



Perennial aquatic herbs with alternate dissected or palmately 

 lobed leaves, the ultimate segments of the submersed leaves 

 filiform; flowers solitary, rather small, white, borne on peduncles 

 opposite the leaves; sepals and petals usually 5; petals oblong or 

 oval, sometimes yellowish at base; stamens several or numerous; 

 akenes compressed, not margined, nearly beakless, transversely 

 wrinkled. 



Receptacle glabrous; submersed leaves none, the float- 

 ing ones 3-parted. B. lobbii. 

 Receptacle hairy; submersed leaves capillary. 



Floating leaves reniform or orbicular. B. aquatile. 



Floating leaves wanting. B. aquatile pantothrix. 



Batrachium lobbii (Gray) Howell. Stems slender, 15-30 cm. long; floating 

 leaves orbicular in outline, 6-15 mm. wide, 3-parted into oblong lobes, the 

 lateral ones notched at the apex; petals obovate, 4 mm. long; styles slender, 

 three times as long as the ovary; akenes rugose, each tipped with a short beak; 

 receptacle glabrous. 



Lost Lake, Vancouver Island, Macoun, and in western Oregon. 



Batrachium aquatile (L.) Wimm. Water Crowfoot. Stems 5-40 cm. long, 

 slender, growing in water; immersed leaves flaccid, all finely divided into fili- 

 form segments, 8-20 mm. long; floating leaves 1-5, reniform or orbicular, 

 3-5-lobed or parted; petals white, yellow at base, each bearing a naked nec- 

 tariferous pit; akenes thick, transversely wrinkled, the style short; receptacle 

 hairy. 



In ponds, frequent. 



Batrachium aquatile pantothrix (Brot.) Piper. All the leaves immersed and 

 divided into filiform segments. 



In ponds, often with B. aquatile. 



