Philodendron (`Philodendrum') Schott, Wien. Zeitschr. Kunst, Lit., Theater und Mode 3:780. 1829. LECTOTYPE: P. grandifolium (Jacq.) Schott, Arum grandifolium Jacq.
Rafinesque, Fl. Tell. 3:66. 1836 . Type species: Philodendron
grandifolium (Jacq.) Schott
Thaumatophyllum Schott, Bonplandia 7: 31. 1859. Type species: P. spruceanum Schott Elopium Schott, Oesterr. Bot. Zeitschr. 15:34. 1865.Type species: Philodendron surinamense (Miq.) Engl.
Baursia [Hoffmannsegg, Verz. Pfl. 42. 1824, nom. nud.] Post & O. Kuntze, Lexicon Gen. Phanerog. 62. 1903. Type species: Caladium bauersia Reichenbach
Appressed hemiepiphytic climbers or vines with aerial roots, less frequently terrestrial with creeping rhizomatous or deeply rooted stems, rarely short-stemmed true epiphytes, rarely somewhat arborescent in Central America; sometimes with flagelliform shoots; sap usually taniniferous, drying dark, rarely with latex, drying white; stems of monophyllous sympodia with elongated hypopodial internodes; internodes densely rooted at nodes, often much longer than broad or about as long as broad, sometimes broader than long at anthesis, sometimes flattened on one side, often coarsely pale-streaked just below the node, usually green and semiglossy, but often turning gray-green to brownish or reddish-brown in age; juvenile plants usually terrestrial or epiphytic and scandent, the petioles conspicuously sheathed and subtended by inconspicuous intravaginal squamulae; cataphylls (prophylls) of mature stems unribbed or variously ribbed, caducous, marcescent and deciduous or persistent and membranaceous to moderately coriaceous, remaining intact or more commonly decomposing to net-like fibrous remains. Leaves usually long-petiolate; petioles usually with ligulate sheath in juvenile plants, adult plants usually sheathed only at base (except P. sect. Pteromischum), variously shaped in cross-section, firm or spongy, usually smooth, frequently densely pale, short-lineate or pale-striate throughout, sometimes warty or covered with scale-like processes, rarely geniculate apically; blades simple and entire, ovate, cordate, hastate, sagittate, oblong to elliptic or variously divided, trifid, trisect, palmatisect, pinnatifid or bipinnatifid; midrib raised or sunken above, raised below; primary lateral veins pinnate, usually conspicuous, spreading to the margins and running into an antemarginal collective vein; the lowermost primary lateral veins (basal veins) often coalesced on cordate blades, the posterior rib (coalesced basal veins) naked with the sinus or not; interprimary veins sometimes present; secondary lateral and higher order veins transversely reticulate between the secondary veins, sometimes all veins slender with no distinct primary lateral veins; minor veins conspicuous or obscure, usually fine and closely parallel; cross-veins (minute veins extending transversely between the minor veins) sometimes visible; secretory ducts sometimes appearing like veins, linear, short to long, obscured to very distinct on lower surface. Inflorescences 1-several per axil, much shorter than the petioles; peduncles shorter or longer than the spathe; spathe erect, usually coriaceous, entirely persistent, often with large superficial resin canals on inner surface which exude resin, opening widely at anthesis (usually about one day), then reclosing and persisting in fruit, deciduous only on ripening of fruit, frequently colorful, often bicolorous on outside, typically somewhat constricted between tube and blade, convolute at base, tube cylindric to inflated, often red to violet-purple within; blade usually opening widely, becoming more or less boat-shaped at anthesis, usually white within, sometimes tinged reddish; spadix sessile to stipitate, divided into pistillate and staminate portions, each with unisexual flowers; pistillate zone usually greenish, basal, obliquely fused at its base to the spathe, free above, usually much shorter than the staminate portion, and separated from it by a sterile zone of staminodial flowers; intermediate sterile zone cylindric to ellipsoid, much shorter than staminate zone in Central America, usually thicker than staminate zone; staminate zone clavate, white, usually somewhat constricted above the sterile staminate zone; flowers unisexual, naked, closely aggregated in several spirals; staminate flowers 2-6 (usually 4-5) androus, stamens free, adjacent, lacking stomial groove, prismatic to obpyramidal; anthers tetrasporangiate, with microsporangia embedded in the abaxial surface of the anther, columnar in shape, elliptic, ovate to rhombic in cross-section, sessile to subsessile, connective thick, apically truncate, usually irregularly 4-5-sided, overtopping thecae; thecae oblong or elliptic, emarginate at the base, dehiscing apically by short, ragged lateral pore, endothecial thickenings lacking; pollen extruded in strands or mixed with resin secretion or exuded in amorphous masses, inaperturate, ellipsoid or oblong or occasionally elongate, medium sized (mean 40 microns, range 28-54 microns), mostly perfectly psillate, sometimes minutely verruculate, scabrate or fossulate to clearly punctate, subfossulate, subfoveolate or subverrucate; sterile staminate flowers naked, usually prismatic, truncate and usually more irregular than fertile flowers and lacking thecae; pistillate flowers with gynoecium syncarpous, ovoid, subcylindric, cylindric or obovoid, 3-9 (14) locular in Central America (2-locular in P. sect. Philopsammos and to 47-locular in P. subg. Meconostigma in South America); locules equal the number of carpels; ovules 1 to several to numerous (to ca 30) per locule, usually hemiorthotropous, rarely hemianatropous, ascending on moderately long or sometimes short funicles; placentation axile, sub-basal or basal; stylar region as broad as or sometimes slightly narrower than ovary; style short, unlobed, with or without boss (see definition under Style type-D), funnel or annulus; central style dome usually lacking; stigma sessile, hemispherical to lobulate. Berries subcylindroid to obovoid, exposed by the re-opening of the spathe, white, whitish-translucent, red or orange; seeds few to many per berry, oblong to ellipsoid or ovoid-oblong, testa rather thick, striate-costate, rarely sarcotestate; embryo axile, straight, elongate, endosperm copious; chromosomes: 2n= 30,32,34,36,(26,48). Species ca. 700, Central Mexico to Argentina; West Indies (occurs in all countries of Central and South America except Chile and Uruguay: Argentina, Belize, Bolivia, Brazil, Colombia, Costa Rica, Ecuador, French Guiana, Greater Antilles, Guatemala, Guayana, Honduras, Lesser Antilles, Mexico, Nicaragua, Panama, Paraguay, Peru, Surinam, Trinidad, Uruguay and Venezuela.