664 FLORA. 



2-parted. Petals 2, notched. Stamens 2, alternate with the petals. Ovary 1-2- 

 celled; ovules usually I in each cavity. Fruit obovoid, indehiscent, bristly with 

 hooked hairs. [Named for Circe, the enchantress.] Abvut 5 species, of the 

 northern hemisphere. Besides the following, another occurs c n the Pacific Coast. 



Fruit 2-celled ; leaves mainly of an ovate type. 



Hairs of the fruit stiff, copious. i. C. Lutetiaua. 



Hairs of the fruit weak, few. 2. C. intermedia. 



Fruit i-celled ; leaves mainly of a cordate type. 3. C. alpina. 



1. Circaea Lutetiana L. ENCHANTER'S NIGHTSHADE. (I. F. f. 2610.) 

 Finely pubescent, at least above; stem 3-6 dm. high. Leaves ovate, acuminate 

 at the apex, rounded or rarely slightly cordate at the base, remotely denticulate, 

 5-10 cm. long; pedicels 4-8 mm. long, reflexed in fruit; bracts deciduous; flowers 

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

 with stiff hooked hairs. In woods, N. S. to western Ont, S. Dak., Ga., Neb. and 

 Kans. Also in Europe and Asia. June-Aug. 



2. Circaea intermedia Ehrh. Resembling the preceding species in habit, 

 glabrous or sparingly pubescent above ; stems 2-5 dm. tall. Leaves ovate or ovate- 

 lanceolate, 4-8 cm. long, repand or sharply denticulate, cuneate or cordate at the 

 base; fruit obovoid, 3-3.5 mm. long, with very slender, weak, hooked hairs orgla- 

 brate. In woods, Me. and Vt. Also in Europe. Summer. 



3. Circaea alpina L. SMALLER ENCHANTER'S NIGHTSHADE. (I. F. 2611.) 

 Smaller, 7-20 cm. high, weak, glabrate or pubescent above. Leaves ovate, acute 

 or acuminate at the apex, more or less cordate at the base, coarsely dentate, 2.5-5 

 cm. long; flowers about 2 mm. broad; pedicels 3-4 mm. long, reflexed in fruit; 

 fruit narrowly obovoid, about 2 mm. long, covered with weak, soft, hooked hairs. 

 In cold moist woods, Lab. to Alaska, Ga., Ind., Mich, and S. Dak. Also in Europe 

 and Asia. July-Sept. 



Family 4. TRAPACEAE Dumort. 

 Water-nut Family. 



Aquatic herbs, with opposite pinnatifid submerged leaves, and clus- 

 tered rhombic-ovate dentate floating ones with inflated petioles. Flowers 

 perfect, axillary, solitary, short-peduncled. Calyx-tube short, the limb 

 4-parted, the lobes persistent. Petals 4, sessile, inserted on the perigy- 

 nous disk. Stamens 4, inserted with the petals ; filaments subulate-filiform. 

 Ovary 2-celled, conic above ; style subulate ; ovule i in each cavity. Fruit 

 coriaceous or bony, large, 2-4-spinose or swollen at the middle, i -celled, 

 i -seeded, indehiscent. Seed inverted. A single genus of 3 species, na- 

 tives of Europe, tropical Asia and Africa. 



i. TRAPA L. 

 Characters of the family. [Latin, from Calcitrapa, the Caltrop.] 



i. Trapa natans L. SWIMMING WATER-NUT. WATER-CHESTNUT. WATER- 

 CALTROP. (I. F. f. 2612.) Rooting in the mud. Submerged leaves, pectinately 

 dissected, 2-10 cm. long, floating leaves in a rosette, their blades rhombic -ovate, 

 sharply dentate above, broadly cuneate and entire below, about 2.5 cm. wide, gla- 

 brous and shining above, the conspicuous veins of the lower surface beset with short 

 stiff hairs; flowers white, about 6 mm. broad; fruit 2-5 cm. long, armed with 4 

 somewhat recurved spines. Nat. in ponds ' and streams, eastern Mass, and near 

 Schenectady, N. Y. Native of Europe. June-July. 



Family 5. HALORAGIDACEAE Kl. & Garcke. 

 Water-milfoil Family. 



Perennial or rarely annual herbs, mainly aquatic, with alternate or 

 verticillate leaves, the submerged ones often pectinate-pinnatifid. Flowers 

 perfect, or monoecious, or dioecious, axillary, in interrupted spikes, solitary 

 or clustered. Calyx-tube adnate to the ovary, its limb entire or 2-4- 



