. An illustrated flora of the northern United States, Canada and the British possessions, from Newfoundland to the parallel of the southern boundary of Virginia, and from the Atlantic Ocean westward to the 102d meridian. Botany; Botany. Genus i. RIVER-WEED FAMILY. 205 Family 43. PODOSTEMACEAE Lindl. Nat. Syst. Ed. 2, 190. 1836. River-weed Family. Small aquatic fresh-water mostly annual fleshy herbs, the leaves usually poorly dififerentiated from the stem, the whole structure commonly resembling the thallus of an alga or hepatic, the small usually perfect flowers devoid of any perianth and subt
. An illustrated flora of the northern United States, Canada and the British possessions, from Newfoundland to the parallel of the southern boundary of Virginia, and from the Atlantic Ocean westward to the 102d meridian. Botany; Botany. Genus i. RIVER-WEED FAMILY. 205 Family 43. PODOSTEMACEAE Lindl. Nat. Syst. Ed. 2, 190. 1836. River-weed Family. Small aquatic fresh-water mostly annual fleshy herbs, the leaves usually poorly dififerentiated from the stem, the whole structure commonly resembling the thallus of an alga or hepatic, the small usually perfect flowers devoid of any perianth and subtended by a spathe-like involucre, or in some genera with a 3-5-cleft mem- branous calyx. Stamens hypogynous, only 2 in the following genus, numerous in some others; filaments united or distinct; anthers 2-celled, the sacs longitudinally dehiscent. Ovary stalked or sessile, 2-3-celled; ovules usually numerous in each cell, anatropous; styles 2 or 3, short. Capsules 2-3-celled, ribbed. Seeds numer- ous, minute, without endosperm; embryo straight. About 21 genera and 175 species, mostly in the tropics, only the following North American. I. PODOSTEMUM Michx. Fl. Bor. Am. 2: 164. pi. 44. 1803. Habit of the several species various. Flowers sessile or very nearly so in the spathe-like involucre. Perianth none. Stamens 2, their filaments united to near the summit; anthers 2, oblong or oval. Staminodia 2, filiform. Ovary ovoid, 2-celled; stigmas 2, nearly erect, short, subulate. Capsule ovoid, 6-io-ribbed, 2-vaIved. [Greek, stalked-stamens.] About 12 species of rather wide geographic distribution, the following typical. Besides the following, another occurs in the southern United States. I. Podostemum. ceratophyHum Michx. River- weed. Thread-foot. Fig. 2130. Podostemum ceratophylhtm Michx. Fl. Bor. Am. 2 : 165. 1803. Plant dark green, rather stifif, firmly attached to stones in running water, densely tufted, I'-io' long, the leaves narrowly linear, sheathing at the base, commonly split
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1913
