inflorescence axillary from the stem or rootstock, from a spathe; flowers solitary 

 or in several- to many-flowered spikes or panicles, perfect, more or less irregular; 

 perianth salverform of funnelform, the tube mostly well-developed, free from 

 the ovary, the 6 lobes similarly colored; stamens 3 or 6, inserted in throat of 

 perianth, mostly unequal or dissimilar, the anthers introrse; style 1; stigma 3-lobed 

 or 6-toothed; ovary superior; fruit a perfect or incompletely 3-celled many-seeded 

 capsule or a 1 -seeded utricle; seeds ribbed. 



About 30 species in a half dozen genera in temperate and tropical regions. 



1. Stamens 6; perianth funnelform (2) 



1. Stamens 3; perianth salverform (3) 



2(1). Plants typically free-floating; fruit a many-seeded dehiscent capsule 



1. Eichhornia 



2. Plants rooted in mud; fruit a 1-seeded utricle ..„ 2. Pontederia 



3(1). Perianth regular or nearly so; style usually stout, about as long as or 

 shorter than the short stamens 3. Heteranthera 



3. Perianth markedly zygomorphic; style slender, almost as long as the long 



stamen 4. Eurystemon 



1. Eichhornia Kunth Water-hyacinth 



Floating aquatic herbs, rooting at nodes; submersed leaves (when present) long 

 and narrow; aerial leaves broad, the petiole usually spongy-inflated; inflorescence 

 pedunculate, spicate to paniculate, from a spathe, the spathe subtended by a 

 sheath that often has a small dilated blade; perianth funnelform, slightly 2-lipped; 

 stamens 6, the 3 upper all included, the 3 lower more exserted; anthers oblong, 

 basifixed; filaments irregularly adnate to the perianth; ovary 3-celled; capsule 

 membranaceous, many-seeded. Also spelled Eichornia. 



About six species in the tropics and warm temperate regions of America and 

 Africa. 



The plants provide an ideal haven for minute animal life that provide food 

 for fish and bird life. Their aggressive weediness, however, off"sets any value 

 that they may otherwise have. They are notorious for clogging and desiccating 

 canals and waterways in the southern United States. They are a favorite food of 

 the manatee. 



1. Petioles inflated at the base; plants with a short naked stem bearing new 

 plants at the nodes; peduncle below the flowers exserted from the 

 spathe; perianth lobes entire 1. E. crassipes. 



1. Petioles not inflated; plants with a continually growing stem, bearing leaves 

 for its entire length; peduncle below the flowers included in the 

 spathe; perianth lobes marginally erose 2. E,. azurea. 



1. Eichhornia crassipes (Mart.) Solms. Fig. 305. 



Leaf blade suborbicular to broadly elliptic, leathery, to 1.5 dm. long and 

 wide; inflorescence a loose terminal spike; flowers showy, light-blue to bluish- 

 purple, 4-6 cm. long and broad. Piaropiis crassipes (Mart.) Britt. 



Ponds, streams and ditches in s. and e. Tex., Apr.-July; from Va. s. to Fla., 

 w. to Mo. and Tex.; also Calif., Mex., W.I., C.A. and S.A. 



A beautiful, noxious weed! 



2. Eichhornia azurea (Sw.) Kunth. 



Except for the uninflated petioles and cross-margined perianth lobes, this 

 species is quite similar in habit to E. crassipes. 



It also grows in the same kind of habitats. Rather widespread in Latin Am., 

 apparently introd. in s. Tex., July. 



598 



