IOWA ACADEMY OF SCIENCES 
155 
Cratty, K. 1. Proceedings of the Iowa Academy of Sciences, 1903, Vol. II, 
p. 21G, 1904. 
Mueller, II. A. Proceedings of the Iowa Academy of Sciences, 1903, Vol. 11, 
p. 277, 1904. 
Peck, Morton E. Proceedings of the Iowa Academy of Sciences, 1904, Vol. 
12, p. 204, 1905. 
7. DIOSCORIACEAE Lindl. Nat Syst i^d. 2, 359. 1836. 
Yam Family. 
This family is represented in the Iowa flora by the following genus 
and species: 
• 1. DIOSCOREA L. Sp. PI. 1032. 1753. 
1. Dioscorea villosa L. Sp. PI. 1033. 1753. Wild Yam-root. 
A twining vine, from a knotted horizontal woody rootstock, which is 
an inch or less in diameter. Stem 4 — 12 feet long, glabrous; leaves thin, 
ovate, entire, alternate, or the lower ones opposite or verticillate in 
fours, 2 — 6 inches long, 1 — 4 inches wide, 9 — 13-nerved, green and gla- 
brous above, pale and frequently minutely pubescent beneath, apex acum- 
inate, base cordate; petioles slender, 2 — 7 inches long; flowers greenish 
yellow, on very short pedicels, the staminate about one line broad and in 
drooping panicles which are 3 — 6 inches long, the pistillate about 3 lines 
long and in drooping spicate recemes; perianth 6-parted, greenish, ad- 
herent in the fertile plant ‘to the 3-celled ovary; stamens 6, inserted at 
the bases of the perianth-segments; style 3, distinct; capsule 3-valved, 
3-angled, membranous, yellowish green, 7 — 12 lines long, strongly 
3-winged, with one or two flat thin winged seeds in each cavity. 
This species ranges from Rhode Island to Ontario and Minnesota, 
south to Florida and Texas. In Iowa the species seems to be conflned 
to the central, eastern, and southern portions, where it is rather common. 
The flowers appear in June and July and the fruit ripens in August and 
September, remaining on the vines until late into the winter season. The 
habitat is moist soil in thickets and along borders. Type locality: 
"Hahitat in Virginia, Florida.” 
Specimens in the writer’s herbarium are from Winneshiek, Dubuque, 
Johnson, Van Buren, Appanoose, Decatur, Ringgold and Union counties. 
Professor Bessey reported the species from Story, Floyd and Poweshiek 
counties; Professor Fink from Fayette county; Barnes, Reppert and 
Miller from Scott and Muscatine counties; and Peck from Hardin county. 
Parry, C. C. Owen’s Report of the Geological Survey of Wisconsin, lowm 
and Minnesota, p. 619, 1852. 
Bessey, C. E. Fourth Biennial Report of the Iowa State Agricultural Col- 
lege, p. 122, 1872. 
Arthur, .7. C. Contributions to the* Flora of Iowa, p. 31, 1876. 
Hitchcock, A. S. Transactions of the Academy of Science of St. Louis, Vol, 
5, p. 519, 1892. 
Fink, Bruce. Proceedings of the low'a Academy of Sciences, 1896, Vol. 4, p. 
103, 1897. 
Fitzpatrick. T. J. Proceedings of the Iowa Academy of Sciences, 1897, Vol. 
5, p. 129, 1898. 
