Flora of North America species comparison

Leaf shape is highly variable in Peltandra virginica, and different forms have been recognized taxonomically, both at the specific and infraspecific levels. Since Because leaf shape varies within populations and even within an individual clump of plants, P. virginica is treated here as a single taxon.

Populations of Peltandra virginica are most common along the Atlantic Coastal Plain, but its range appears to be actively expanding. Since 1978, the species was reported as new to the floras of Iowa, Kansas, Minnesota, West Virginia, and Wisconsin, and introduced populations may persist in Oregon and California. Fruits and seeds of P. virginica are a food for wildlife, especially waterfowl, and their use by migratory birds is an important factor in the spread of this species.

The flowers of Peltandra virginica are pollinated by a chloropid fly, Elachiptera formosa (Diptera: Chloropidae), which uses the inflorescence as a mating site and a larval food source. Eggs are deposited within the inflorescence, and the emerging larvae feed on the rotting male portion of the spadix. The fruits are primarily dispersed by water, although animals also play a role.

Peltandra virginica may have been an important food plant for eastern Native Americans, especially in the mid-Atlantic coastal region from Pennsylvania to Virginia, where the plants are now common and grow in large, dense populations. Historical accounts mention use of the rhizomes as well as the leaves, fruits, and seeds as food.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Araceae are best characterized by the inflorescence, a fleshy cylindric or ovoid, unbranched spadix subtended or surrounded by a spathe. True spathes are absent in the Nearctic genus Orontium and in the Australian genus Gymnostachys. Other plant families with a compressed spadix-like inflorescence, such as Piperaceae and Cyclanthaceae, either do not have a structure equivalent to a spathe (Piperaceae) or have early-deciduous bracts (Cyclanthaceae). Plants are usually glabrous, rarely pubescent or spiny (pubescent in Pistia). Many Araceae exhibit typical monocotyledonous parallel leaf venation, but some genera have net leaf venation more typical of dicotyledons.

Infrafamilial classification of the Araceae is under active study. The only classification of the family to date to utilize modern phylogenetic techniques (S. J. Mayo et al. 1997) recognizes seven subfamilies, of which three are represented in native temperate North American aroid flora: Orontioideae (Orontium, Symplocarpus, Lysichiton); Calloideae (Calla); and Aroideae (Peltandra, Arisaema, and Pistia). Acorus, a genus historically included in Araceae, is treated as a separate family in theat flora based on extensive morphologic and chemical evidence that supports its removal from Arales (M. H. Grayum 1987).

The number of genera of Araceae occurring in temperate North America is low in comparison with other continents, and primitive taxa are disproportionately represented. Orontioideae and Calloideae, which include four of the seven native genera found in the flora area, are the basal clades within Araceae. Plants in these subfamilies possess the primitive states for many characteristics in Araceae and share few derived characteristics with other aroid genera (M. H. Grayum 1990). The more advanced genera native to the flora area include one genus endemic to eastern North America (Peltandra), a pantropical genus with an uncertain native distribution (Pistia), and a genus clearly Eurasian in origin (Arisaema).

Araceae contain crystals of calcium oxalate, which are often cited as causing the intense irritation experienced when handling or consuming the raw plant tissue of many genera in the family. This supposition is contradicted by the fact that although irritation generally is not produced by properly cooked plants, the crystals remain after heating. Other compounds must therefore be involved with causing this reaction. Studies of Dieffenbachia demonstrated that a proteolytic enzyme, as well as other compounds, are responsible for the severe irritation caused by this plant and that raphides of calcium oxalate do not play a major role (J. Arditti and E. Rodriguez 1982). Whether irritation is caused by enzymes or crystals, that aspect of Araceae has resulted in aroid genera being included in many lists of poisonous plants (e.g., K. F. Lampe and M. A. McCann 1985; G. A. Mulligan and D. B. Munro 1990; K. D. Perkins and W. W. Payne 1978).

Despite the toxic effects of Araceae, species of several genera are cultivated as food plants, mainly as subsistence crops in tropical areas. The major edible Araceae are Colocasia esculenta and several species of Xanthosoma, grown primarily for their corms and sometimes for their leaves. Most North American species of Araceae were historically used by Native Americans, as both food and medicine (T. Plowman 1969). The family, is currently more valued for its many ornamental species, and is the most important family in North America for indoor foliage plants (T. B. Croat 1994). Araceae commonly grown as ornamentals in American homes include species of Aglaonema (Chinese-evergreen), Anthurium, Caladium, Dieffenbachia (dumbcane), Epipremnum (golden pothos), Philodendron, Spathiphyllum, Syngonium, and Zantedeschia (calla-lily).

Plants of some cultivated species of Araceae escape and may persist or naturalize, especially in warmer climates. One of these species, Colocasia esculenta, is widespread enough to warrant full inclusion in the flora, but other introduced species of Araceae are very local in occurrence. Uncommon species represented by herbarium specimens or literature reports as escaped or persisting from cultivation are listed (table 203.1) with distinguishing characteristics and areas of occurrence.

Genera 105, species more than 3300 (8 genera, 10 species in the flora; species in 10 additional genera may persist locally within flora area, see table 203.1).

Table 203.1: [see original page on floranorthamerica.org]

(Discussion copyrighted by Flora of North America; reprinted with permission.)