CROWFOOT FAMILY 89 



Sepals decidetUy dilated at the apex. 



Sepals acute or short-acuminate; plant in age glabrate; leaf-segments lanceolate. 



5. V. Jonesii. 

 Sepals obtuse or merely acutish; plant permanently villous; leaf-segments linear. 



6. V. eriophora. 



7. ATRAGENE L. Bell Rue, Purple Virgin's Bower. 



Leaves merely ternate. 



Staminodia usually decidedly spatulate; leaflets variously toothed or cleft, not long- 

 acuminate. 

 Lobes or teeth of the leaves rounded or obtuse at the apex ; sepals ovate. 



1. A. diversiloba. 

 Lobes or teeth of the leaves acute or acuminate; sepals lanceolate. 



2. ,4. grosseserrata. 

 Staminodia linear or none; leaflets entire or crenate above the middle, long-acuminate. 



3. A. Columbiana. 

 Leaves twice or thrice ternate; staminodia usually linear or lacking. 



Secondary leaflets merely toothed or cleft. 



Secondary leaflets broadly ovate, with broadly ovate teeth. 4. A. repens. 



Secondary leaflets lanceolate, with lanceolate or ovate-lanceolate lobes or teeth. 



5. .4. pseudoalpina. 

 Secondary leaflets divided to near the niidrib. 6. A. tenuiloba. 



8. MYOSURUS L. Mouse-tail. 



Achenes with a flat back, only slightly carinate, and tipped with a very short appressed 

 beak. 1. M. minimus. 



Achenes stronglj carinate on the back, tipped with a subulate, ascending beak. 

 Beak more than half as long as the achene proper; spike short and dense. 



2. M. aristatus. 

 Beak very short; spike of the achenes long and slender. 3. M. leplurus. 



9. BATRACHIUM S. F. Gray. White Water Crowfoot. 



Leaves all submerged and finely dissected, with linear to capillary divisions. 



Divisions of the leaves rather few, flat, 0.5-1.5 mm. wide. 1. B. Porteri. 



Divisions of the leaves very slender, filiform or capillary. 



Beak of the achenes nearly 1 mm. long. 2. B. longiroslre. 



Beaks of the achenes minute or none. 



Petals 5-7 mm. long, broadly obovate; stamens many. 



Primary divisions of the leaves 1-1.5 cm. long, rather rigid, scarcely col- 

 lapsing when withdrawn from the water. 3. B. trichophyllum. 

 Primary divisions of the leaves 1.5-3 cm. long, flaccid, collapsing when 

 withdrawn from the water. 4. B. flaccidum. 

 Petals less than 5 mm. long, oblong-obovate; stamens 5-12. 

 Stem slender, but not capillary; leaves not very flaccid. 



5. B. Drouelii. 

 Stem capillary-filiform; leaves very fiaccid. 6. B. confervoides. 



Upper leaf-blades floating, reniform, merely cleft or toothed, the rest submersed and 

 with capillary divisions. 7. B. Grayanus. 



10. RANUNCULUS (Tourn.) L. Crowfoot, Buttercup. 



Achenes smooth. 



Leaves linear to oval, entire, or merely denticulate or crenate, none divided or cleft. 



I. Flammulae. 

 Some of the leaves at least cleft. 



Sepals black-hairy. II. Nivales. 



Sepals not black-hairy. 



Some of the basal leaves entire. 



Basal leaves linear or divided into 3 linear divisions. V. Digitati. 



Basal leaves elliptic to reniform. III. Glaberrimi. 



None of the leaves entire. 



Neither floating water plants nor creeping mud plants, if rooting at the 

 nodes, the leaves not palmately lobed or dissected. 

 Achenes turgid, marginless. 



Petals much exceeding the sepals. 



Basal leaves not divided to the base. IV. Affines. 



Leaves all divided to the base; achenes glabrous. 



Leaves ternate, with simple Unear divisions; plants very 



low, 0.5 dm. or less. V. Digitati. 



Leaves 2-3 times ternate; plants 5-20 cm. high. 



VI. Tritern.\ti. 

 Petals scarcely exceeding the sepals. 



Plants low, less than 1 dm. high. VII. Pygmaei. 



Plants taller, 3-6 dm. high. VIII. Abortivi. 



Achenes compressed, with a distinct margin. 



Beak of the achenes strongly hooked ; heads of fruit globose. 



IX. Recurvati. 

 Beak of the achenes straight or nearly so; achenes in ours glabrous. 

 Beak short. 



Leaves, at least the basal ones, pinnately ternate, the ter- 

 minal division at least petioled. X. Repentes. 



