226 AEACEAE 



Plants normal, with the flowers in a spadix, this sometimes subtended by or partly 



enclosed in a spathe. Fam. 1. Araceae. 



Plants reduced to small floating thalloid structures, with one or few flowers. Fam. 2. Lemnaceae, 



Family 1. ARACEAE Neck. Arum Family. 

 Fleshy, mostly acanleiseent herbs, with short or elongated rootstocks. Leaves 

 basal : blades simple, sometimes' divided. Flowers perfect, monoecious or dioe- 

 cious, borne in a dense thick spadix, the staminate above the pistillate. Spadix 

 subtended by or enclosed in a Spathe. Perianth of 4—6 scale-like members, or 

 wanting. Androecium often of ,4-10 stamens. Filaments very- 'short. ' Anthei's 

 2-4-eeired,^with, thick truncate connectives : sacs opening by dorsal slits or pores. 

 Gynoecium of a single carpel or several united carpels; Ovary lr-sevei*al-celled. 

 Stigma terminal, minute. Ovules 1-several in each cavity. Fruit a berry or 

 utricle. Seeds with a sn^ooth or sculptured testa. r . - - • - ^ 



Flowers monoecious or dioecious: perianth wanting. ,.». ^ ... 



Spadix free: pistillate flowets numerous.' 



Leaf-blades 3=-many-divided : axis of thp spadix naked above.f-f 



Leaf-blades palmately divided: spathe involute below, hooded above: spadix 



included, terete or Obscurely angled. 1. Arisaema. 



Leaf-blades pedately divided: spathe convolute throughout: spadix exS(Mied, 



more or less flattened or 2-edged. 2. Muricauda. 



Leaf-blades simple: axis'ot the sgadix completely covered, wfah flowers. ■ 3. Peltandra. 



Spadix adnate to the spathe: pistillate flower solitary. - 4. Pistia. 



Flowers perfect: perianth of several scale-like members. 



Spadix surrounded by a spathe. 5.^ Spathyema. 



Spadix naked, merely subtended by a spathe. ■ • -■ ■■ ■ r' ^ • . 



Spadix terminating the club-shaped scape-. • ,., .^ 6i Orontium. 



Spadix borne somewhat laterally on the leaf-like scape. ^ ' . 7. Acorus. 



l.-ARISAilMA Mart, t 

 Scapose fleshy herbs, with acrid corms, Leaves basal, 1-3 erect: blades pa.1mately 

 lower part of its markedly differentiated fertile portion, the sterile portion club-shaped, 

 included. Spathe eornueopia-like, convolute below, dilated above. Flowers destitute of a 

 perianth, dioecious or monoecious: staminate of 4 nearly sessile 2-4-celIed anthers, each 

 opening by confluent slits at the apex. Pistillate flowers several, each with a 1-eclIed 

 ovary. Stigmas peltate-capitate. Ovules l-several, orthotropous. Fruits subglobose, 

 red, in conspicuous heads. Endosperm copious. Jack-in-the-Pulpit. Indian Turnip. 



Leaf-segments 3: spathe acuminate or acute 



Sterile part of the spadix 1-2 mm. thick: fruits 4-5 mm. in diameter. 1. A. pusillnm. 



Sterile part of the spadix 4-6 mm. thick: fruits 8-12 mm. in diameter. 



Dilated portion of the spathe mainly purple and brown, less than twice as 



long aa broad, acute or short-acuminate. _ 2. A. triphyllum. 



Dilated portion of the spathe green, over twice as long as broad, long-acumi- 

 nate. 3- A. acuminatum. 

 Leaf-segments 5 (the lateral ones sometimes more or less united J : spathe abruptly 



short-pointed. 4- ^- qumotum. 



1. Arisaema pusillum (Peck) Nash. Conn small, subglobose or spheroidal: leaves 

 usually 2, or 1 on staminate plants, 2-4 dm. tall; petioles 5-18 cm. long, or 7-10 cm. 

 in the case of the second leaf; segments 3, thinnish, ovate to oblong or elliptic, acumi- 

 nate, 5-13 cm. long, green on both sides: scapes shorter than' the petibles:^ Spathe 

 with the convolute portion 3-5 cm. long, white without, red-brown: within, th^ dilated 

 part 5-6 cm. long, acuminate, green without, dark red-brown. within, or <9liiiost black: 

 spadix slender, 1-2 mm. thick; staminate -1-5 cm. long; pistillate 5-6:' cm. long: 

 anthers purple: fruits red, 4-5 mm. in diameter. ' 



In open swamps and deep woods. New York to Kentucky and Georgia. Late spring-and summer. 



2. Arisaema triphyllum (L.) Torr. Corm globose or spherical, sometimes 10 

 cm. in diameter: leaves usually 2, sometimes solitary, 2-16 dm. tall; segments 3, ovate 

 to elliptic or the middle one obovate, sessile, 8-30 cm. long, acut^ oi* acumin^e, erose, 

 the lateral ones sometimes lobed at the base : scape erect, shorter than the petiolesi, 

 simple: spathe Avith the lower portion white, the dilated portio^i often- ^triped Aj.uth 

 purple, or brown and green, acuminate : spadix stout, 4-6 mm. thick ; staininate 4-9 

 cm. long ; pistillate 5-10 cm. long : fruits bright red, 10-12 mni! in diametet. ' ' ^ 



In swamps or on shaded hillsides, Nova Scotia to Minnesota, Kansas, Florida and Louisiana. --Sllring. 



3. Arisaema acuminatum Small. Similar to .4. fri;)/i2/??t"'i in habit, but much'niore 

 slender and delicate. Leaves 3-5 dm. tall ; segments lanceolate to elliptic orovatedanceo- 



