GUNNERACEAE 849 



15. Gaura villosa Torr. Stem erect or nearly so, 3-9 dm. tall, canescent or villous : 

 leaf-blades varying from spatulate to lanceolate or sometimes nearly linear, 2.5-7.5 cm. 

 long, sinuate-toothed or pinnatifid, acute or acuminate : buds canescent : petals 10-14 mm. 

 long : fruit glabrous, the body oblong, wing-angled, abruptly narrowed into the much 

 shorter and relatively slender pedicel-like base. 



On plains or prairies, Kansas to Arkansas aud Texas. Summer and fall. 



18. STENOSIPHON Spach. 



Perennial herbs, with erect stems. Leaves alternate : blades sessile, narrow. Flowers 

 in elongated terminal spikes. Hypanthium filiform, much prolonged beyond the ovary. 

 Sepals 4. Petals white, with clawed blades. Stamens 8, declined, the filaments without 

 scales at the base. Ovary 1 -celled : stigma as in Gaura. Fruit 8-ribbed, indehiscent, 1- 

 celled, 1-seeded. Seed pendulous. 



1. Stenosiphon linifolium (Nutt. ) Britton. Stems slender, glabrous, 6-15 dm. tall : 

 leaf-blades lanceolate, linear-lanceolate or linear, 2.5-5 cm. long, acuminate or acute at 

 the apex, entire : spikes dense, narrow, sometimes 3 dm. long at maturity : sepals very 

 narrow, 8-10 mm. long : corolla 8-12 mm. broad : fruit ovoid, pubescent, 2-3 mm. long, 

 very much shorter than the linear-subulate bracts. 



On prairies, Nebraska and Colorado to tlie Indian Territory and Texas. Summer. 



19. CIRCAEA L. 



Low perennial herbs, with watery or relatively succulent stems. Leaves opposite : 

 blades petioled. Flowers small, in racemes. Hypanthium slightly prolonged beyond the 

 ovary. Sepals 2. Petals 2, white, notched. Stamens 2, alternate with the petals. Ovary 

 1-2-celled. Ovules usually 1 in each cavity. Fruit obovoid, indehiscent, bristly with 

 hooked hairs or rarely glabrous. Enchanter's Nightshade. 



Fruit 1-celled : bracts small : leaf-blades mainly of a cordate type. 1. C. alpina. 



Fruit 2-celled : bracts obsolete : leaf-blades mainly of an ovate type. 2. C. Lutetiana. 



1. Circaea alpina L. Stems 7-20 cm. tall, weak, glabrate or pubescent above : leaf- 

 blades ovate, mostly cordate at the base, 2.5-5 cm. long, acute or acuminate at the apex, 

 coarsely dentate : pedicels 3-4 mm. long : bracts small : corolla about 2 mm. broad : fruit 

 narrowly obovoid, about 2 mm. long, covered with weak soft hooked hairs, 1-celled. 



In cold moist woods, Labrador to Alaska, Georgia, Indiana and South Dakota. Also in Europe 

 and Asia. Summer and fall. 



1. Circaea Lutetiana L. Stems pubescent, at least above, 3-6 dm. high : leaf-blades 



ovate, 5-10 cm. long, acuminate at the apex, mainly rounded or rarely slightly cordate at 



the base, remotely denticulate: pedicels 4-8 mm. long: bracts deciduous or obsolete: 



corolla about 3 mm. broad : fruit broadly obovoid, nearly 4 mm. long, densely covered 



with stiff hooked hairs, 2-celled. , 



In woods. Nova Scotia to Ontario, South Dakota, Georgia and Kansas. Also in Europe and Asia. 

 Summer. 



Family 8. GUNNERACEAE Endl. Water Milfoil Family. 



Perennial, or rarely annual, caulescent mainly aquatic or amphibious herbs. 

 Leaves alternate or whorled : blades all alike or of two kinds, the submerged 

 finely divided, the emersed entire or merely toothed. Flowers perfect or monoe- 

 cious, solitary or clustered, either in the axils or in terminal spikes. Calyx of 

 2-4 sepals. Corolla of 2-4 small petals, or wanting. Androecium of 1-8 com- 

 paratively large stamens. Filaments sometimes elongated. Anthers 2-celled. 

 Gynoecium of 1-4 sometimes united carpels. Ovary 1-4-celled, inferior, 2-8- 

 augled or rarely 2-4-winged. Styles wanting. Stigmas 1-4, papillose, or 

 plumose. Ovides 1-4, anatropous, pendulous. Fruit an angled ribbed or winged 

 nutlet or drupe with 1-4 carpels. Embryo in the fleshy endosperm. [Haloragi- 

 daceae Kl. & Garcke.] 



Fruit 3-4-angled. 1. Proserpinaca. 



Fruit of 2-4 bony nutlets. 2. Myriophyllum. 



1. PROSERPINACA L. 



Aquatic herbs, with glabrous foliage. Stems usually simple, creeping. Leaves alter- 

 nate : blades toothed to pectinate-pinnatifid, the lower ones more finely dissected than the 

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