Flowering Plants: Lilies to Orchids

Dioscoreaceæ -- Wild Yam Family

146 I L I L I E S T 0 0 R C H I D S COMMON NAME: Carrion Flower. HABITAT: Moist woods. RANGE: Ontario to Minnesota, south to northeastern Oklahoma and Tennessee. ILLINOIS DISTRIBUTION: Occasional in the northern onehalf of Illinois, becoming extremely uncommon in the southern counties. Smilax ecirrata, together with S. illinoensis, are the only non-climbing species of the genus in Illinois. Tendrils often are lacking. The inflorescence contains fewer flowers than in any of the other herbaceous species in Illinois. Smi.lax illinoensis differs by its proportionately longer petioles and its narrower leaves. The flowers appear during May and the first part of June. Although the epithet is customarily spelled ecirrhata, the original spelling was without the "h". The lectotype, selected by Mangaly, was collected by G. Engelmann in 1835 from Belleville, Illinois. DIOSCOREACELE-WILD YAM FAMILY Only the following genus occurs in Illinois. 1. Dioscorea L. - Wild Yam Twining herbaceous vines from rhizomes and tubers; leaves alternate or whorled, net-veined; plants dioecious; inflorescence axillary, the staminate glomerulate or solitary in panicles, the pistillate solitary in interrupted spikes; flowers unisexual, regular ; perianth parts 6, of uniform color; stamens 3 or 6; ovary 3-celled, inferior, with 2 ovules per cell; capsule 3-winged, loculicidal ; seeds flat, broadly winged. The cultivated cinnamon vine, D. batatas Dcne., is grown as an ornamental in Illinois, but has not been collected as an escape. KEY TO THE SPECIES OF Dioscorea IN ILLINOIS 1. All leaves (except sometimes the lowermost) alternate; capsule 1.5-2.5 em long; seeds (including wing) 7-14 mm broad; petiole essentially glabrous at point of attachment of blade___ I. D. villosa 1. Lowest leaves whorled, becoming opposite or alternate on the upper part of the stem; capsule 2.5-3.0 em long; seeds (including wing) 15-18 mm broad; petiole puberulent at point of attachment of blade____________________________________2. D. quaternata Dioscorea I 147 70. Smilax ecirrata (Carrion Flower). a. Habit, Xlt b. Inflorescence, Xlt c. Flower, X1Jt 148 I L I L I E S T 0 0 R C H I D S 1. Dioscorea villosa L. Sp. Pl. 1033. 1753. Fig. 71. Dioscorea paniculata Michx. Fl. Bor. Am. 2:239. 1803. Dioscorea paniculata var. glabrifolia Bartlett, Bull. U. S. Bur. Pl. Ind. 189:15. 1910. Diosearea villosa f. glabrifolia (Bartlett) Fern. Rhodora 39: 401. 1937· Leaves alternate, the lowest becoming pseudo-whorled, ovate, acuminate, cordate, 5-10 em long, 3-8 em broad, 7- to 11nerved , glabrous above, glabrous or puberulent beneath; petiole to 7 em long, glabrous or nearly so; staminate inflorescence paniculate, the internodes between the glomerules 2-4 mm long; pistillate inflorescence spicate, interrupted, 5- to 15-flowered; capsule 1.5-2.5 em long, 3-winged; seeds broadly winged, 7-14 mm broad (including the wing); 2n = 6o (Smith, 1937). COMMON NAME: Wild Yam. HABITAT: Dry or moist woodlands. RANGE: Connecticut to Minnesota, south to Texas and Florida. ILLINOIS DISTRIBUTION: Common; probably in every county, although so far not collected in every county. This wild yam has large, thickened rhizomes which are rarely seen because of the great depth where they grow in the soil. Specimens with completely glabrous leaves may be known as f. glabrifolia. A few specimens have been observed, however, where both glabrous and puberulent leaves occur on the same plant. No attempt has been made to plot the distribution of Illinois material based on leaf pubescence . Flowers appear in June and July, with fruits maturing by late August. 2. Dioscorea quaternata [Walt.] J. F. Gmel. Syst. 581.1796. Fig. 72. Anonymas quaternata Walt. Fl. Car. 246. q88. Dioscorea glauca Muhl. Cat. 92. 1813. Dioscorea quaternata var. glauca (Muhl.) Fern. Rhodora 39=399· 1937· Lowest leaves in whorls of 4-7, the middle and upper becoming opposite or alternate, ovate, acuminate, cordate, 5-12 em long, 4-10 em broad, 7- to 11-nerved, green or scarcely glaucous, glabrous above, glabrous or puberulent beneath; petiole 3-9 em long, puberulent at least at point of blade attachment; staminate Dioscorea I 149 c 71. Dioscorea villosa (Wild Yam). a. Habit, Xl~. b. Staminate inflorescence , Xzlf. c. Pistillate inflorescence and young fruits, Xzlf. 150 I L I LIE S T 0 0 R CHID S inflorescence paniculate, the internodes between the glomerules 3-10 mm long; pistillate inflorescence spicate, interrupted, 3to...