228 ARACEAE 



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 adnata to the spathe. Flowers few, monoe- 

 cious: pistillate 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-peduneled, villous, the lower part 

 convolute, 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 Eaf. 

 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 

 members. 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 subter- 

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

 beak, greenish 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 sub- 

 globose, 9-15 mm. thick. [Symplocarpus foetidus (L.) Nutt.] 



In swamps or low grounds, Nova Scotia to Minnesota , Florida and Missouri. Winter or ear ]j spring- 

 Skunk Cabb-^ge. Midas' Ears. 



6, ORONTIUM L. 



Aquatic or swamp-inhabiting herbs, with deeply buried rootstoeks. Leaves basal : 

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

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

 golden yellow, terminal naked. Flowers j)erfect, covering the spadix. Perianth of 4-(5 

 (6 below, 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. Orcntium aquaticum L. Rootstock thick, uneven: leaf-blades thickish, oblong 

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

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

 tered, 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 Loiiisiana. Spring. Golden- 

 club. Bog Torches. 



7. ACORUS L. 



Swamp-inhabiting herbs, with elongated aromatic pungent rootstoeks. 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 renif orm or sagittate : sacs 2, con- 



