9. Nymphoides Hill Floating-heart 



Perennial submersed aquatic plants with floating alternate leaves on long 

 petioles that bear near their summit an umbel of flowers and often a cluster of 

 short spurlike roots; calyx 5-parted; corolla almost rotate, 5-parted, the lobes 

 bearing a glandular appendage near the base; style short or none, the persistent 

 stigma 2-lobed; capsule few- to many-seeded, at length bursting irregularly; seeds 

 papillate, the coat hard. 



A genus of about 20 species; in America, Eurasia and Africa; often placed in 

 the segregate family Menyanthaceae. 



iT Petioles slender, sometimes with clusters of roots just below the leaf blade; 



leaves mostly basal; flowers white, in clusters on the petioles 



1. N. aquatica. 



1. Petioles rather stout, without clusters of roots; leaves mostly from branching 



stems; flowers yellow, axillary 2. N. peltata. 



1. Nymphoides aquatica (Gmel.) O. Ktze. Figs. 1 and 631. 



Plant coarse; leaves mostly basal, suborbicular to reniform, with a deep basal 

 sinus, heavy in texture, smooth and yellowish green on upper surface, dark- 

 punctate or pitted on lower surface, to 15 cm. wide; petiole slender, arising from 

 a cluster of fleshy roots, purple-glandular, to 25 cm. or more long; pedicels to 8 

 cm. long; calyx to 5 mm. long; corolla white, about 15 mm. broad; capsule 

 elongate, to 15 mm. long; seeds glandular-roughened. Limnanthemum trachy- 

 sperinum Gray. 



In ponds and sluggish streams in e. Tex., May-July; from Fla. and Tex., n. 

 locally to s. N.J. and Del. 



2. Nymphoides peltata (Gmel.) O. Ktze. Yellow floating-heart. 



Plant coarse; stem stout, extensively creeping and branching; leaves subtending 

 the umbel, suborbicular, coarsely undulate-dentate, to about 15 cm. long and wide; 

 pedicel often 6 cm. long or more, stout; calyx lobes elliptic-lanceolate, subobtuse. 

 1 cm. long or more; corolla bright-yellow, 2-3 cm. broad, its segments somewhat 

 fringed; anthers 4-5 mm. long; capsule strongly beaked, to 25 mm. long; seeds 

 flat, narrowly winged, with fringelike margins. 



In quiet waters of rivers, lakes and streams, and on wet sandy shores of lakes 

 in s.e. Okla. (McCurtain and Bryan cos.), n.-cen. Tex. and Ariz. (Santa Cruz 

 Co.), June-Sept.; introd. from Eur. for cult, but escapes and has become estab- 

 lished from N.Y. s. to Tex. and Ariz. 



Fam. 109. Apocynaceae Juss. Dogbane Family 



Trees, shrubs, vines or herbs, often with milky juice; leaves opposite or alternate 

 or occasionally verticillate, entire; flowers regular, perfect; calyx gamosepalous, 

 the 5 usually imbricate lobes mostly parted nearly to the receptacle, frequently 

 bearing various glandular appendages within; corolla gamopetalous, varying from 

 salverform or infundibuHform to urceolate or campanulate, the tube sometimes 

 bearing somewhat conspicuous faucal appendages within, the limb 5-parted, the 

 lobes sinistrorsely or dextrorsely contorted in aestivation; stamens 5. alternate 

 with the corolla lobes in the tube, the introrse anthers 4-celled; ovary bicarpellary, 

 the single style surmounted by a massive stigma of diversified structure; fruit 

 follicular (in ours); seeds naked or comose. 



About 180 genera and 1,500 species of cosmopolitan distribution. The family 

 contains many ornamental as well as poisonous plants. 



1. Leaves alternate 1. Amsonia 



1. Leaves opposite or whorled (2) 



1331 



