228 AKACEAE 



4. PISTIA L. 



Free-floating herbs, with fibrous roots. Stems jointed. Leaves clustered at the nodes : 

 blades broadened upward, simple, entire. Spathes axillary, sessile or nearly so, tubular 

 below, spreading above. Spadix adnate to the spathe. Flowers few, monoecious : pistil- 

 late solitary on lower part of spadix : staminate above, subtended by a cup-like involucre. 

 Perianth wanting. Anthers 3-8-celled : sacs opening transversely. Ovary 1-celled. 

 Ovules several, ascending, orthotropous. 



1. Pistia Stratiotes L. Foliage nearly glabrous. Roots furnished with numerous 

 hair-like rootlets : stems elongating : leaves clustered ; blades cuneate or obovate-cuneate, 

 4-13 cm. long, rounded or notched at the apex, prominently nerved beneath : spathes 

 white, or partially so, about 1.5 cm. long, short-peduncled, villous, the lower part convo- 

 lute, the upper part flat, ovate : spadix adnate to the spathe : pistil solitary. 



In still water, Florida to Texas. Also throughout the tropics. WATER LETTUCE. 



5. SPATHYEMA Raf. 



Swamp-inhabiting stinking herbs. Leaves basal : blades ample, cordate, leathery. 

 Scapes erect, partly underground, very thick. Spathe shell -like, leathery, often varie- 

 gated, slightly twisted at the apex. Spadix oblong or globose, completely enclosed in the 

 spathe, short-stalked. Flowers perfect, covering the spadix. Perianth of 4 hooded mem- 

 bers. Stamens 4 : anthers 2-celled ; sacs opening lengthwise, extrorse. Ovary sunken in the 

 spadix, 1-celled : style pyramidal, 4-sided : stigma minute. Ovule solitary, anatropous, 

 suspended. Fruits immersed in the spadix, adnate to the accrescent fleshy perianth. 

 Seed solitary, irregular. Endosperm wanting. [Symplocarpus Salisb.] 



1. Spathyema foetida (L.) Raf. Foliage glabrous. Herbage garlic-scented : leaf- 

 blades ample, 2-9 dm. long, oblong to ovate, obtuse, undulate, thick, truncate or subcor- 

 date at the base : petioles stout, shorter than the blades : scapes erect, mostly subterranean : 

 spathe preceding the leaves, 8-15 cm. long, ovoid, with a more or less curved beak, green- 

 ish or yellowish, mottled with purple : spadix subglobose, 2-2.5 cm. becoming 10-15 cm. 

 in diameter at maturity : fruits spheroidal or globose, green : seeds subglobose, 9-15 mm. 

 thick. \_Symplocarpusfoetidus (L. ) Nutt.] 



In swamps or low grounds, Nova Scotia to Minnesota, Florida and Missouri. Winter or early 

 spring. SKUNK CABBAGE. MIDAS' EARS. 



6. ORONTIUM L. 



Aquatic or swamp-inhabiting herbs, with deeply buried rootstocks. Leaves basal r 

 blades flat. Scapes terete below, enlarged under the spadix. Spathe enclosing the spadix 

 when young, persisting as a sheath-like bract at its base or deciduous. Spadix golden 

 yellow, terminal, naked. Flowers perfect, covering the spadix. Perianth of 4-6 (6 be- 

 low, 4 above), scale-like imbricated sepals. Filaments broader than the anthers, abruptly 

 contracted above. Anther-sacs 2, spreading, opening by oblique valves. Ovary 1-celled, 

 depressed, sunken in the spadix-axis. Ovule solitary, half-anatropous. Utricle green. 

 Seed solitary. Endosperm wanting. 



1. Orontium aquaticum L. Rootstock thick, uneven : leaf-blades thickish, oblong 

 or elliptic, 1-3 dm. long, acute or apiculate, entire, gradually or abruptly narrowed 

 at the base, sometimes lustrous, often inequilateral, petioled : scapes solitary or clustered, 

 terete, or flattened below the spadix, 2-6 dm. long, or elongating and reclining at maturity : 

 spathe bract-like, 4-10 cm. long, 2-keeled on the back, early falling away : spadix yellow, 

 tapering upward, 2-6 cm. long : utricles spheroidal, about 1 cm. thick, few developing. 



In swamps and shallow ponds, central Massachusetts to Florida and Louisiana. Spring. GOLDEN- 

 CLUB. BOG TORCHES. 



7. ACORUS L. 



Swamp-inhabiting herbs, with elongated aromatic pungent rootstocks. Leaves basal : 

 blades linear, sheathing each other and the base of the scape. Scapes erect, 3-angled, 

 keeled on the back, channeled on the front, rather leaf-like. Spathe sword-like, ap- 

 parently a prolongation of the scape. Spadix conic-cylindric, laterally attached, naked. 

 Flowers perfect, crowded on the surface of the spadix-axis. Perianth of 6 concave 

 membranous members. Filaments flattened. Anthers reniform or sagittate : sacs 2, con- 



