1. B. cirrhòsa, Banks. Glabrous; leaves ovate or heart-shaped pointed, entire; petioles dilated at base and partly clasping, but with no distinct sheath or stipules; flowers greenish, 2–5 in a fascicle from the axil of an awl-shaped bract, these crowded in axillary and terminal racemes; pedicel jointed near the base; fruiting calyx with the wing 1´ long.—S. Ill. to S. C. and Fla.
Order 90. PODOSTEMÀCEÆ. (River-weed Family.)
Aquatics, growing on stones in running water, some with the aspect of Sea-weeds, or others of Mosses or Liverworts; the minute naked flowers bursting from a spathe-like involucre as in Liverworts, producing a 2–3-celled many-seeded ribbed capsule;—represented in North America by
1. PODOSTÈMON, Michx. River-weed.
Flowers solitary, nearly sessile in a tubular sac-like involucre, destitute of floral envelopes. Stamens 2, borne on one side of the stalk of the ovary, with their long filaments united into one for more than half their length, and 2 short sterile filaments, one on each side; anthers 2-celled. Stigmas 2, awl shaped. Capsule pedicellate, oval, 8-ribbed, 2-celled, 2-valved. Seeds minute, very numerous on a thick persistent central placenta, destitute of albumen.—Leaves 2-ranked. (Name from ποῦς, foot, and στήμων, stamen; the two stamens being apparently raised on a stalk by the side of the ovary.)
1. P. ceratophýllus, Michx. Leaves rigid or horny, dilated into a sheathing base, above mostly forked into thread-like or linear lobes.—Not rare in shallow streams, E. Mass, to Minn., and southward. July–Sept.—A small olive-green plant, of firm texture, resembling a Seaweed, tenaciously attached to loose stones by fleshy disks or processes in place of roots.
Order 91. ARISTOLOCHIÀCEÆ. (Birthwort Family.)
Twining shrubs, or low herbs, with perfect flowers, the conspicuous lurid calyx valvate in bud and coherent (at least at base) with the 6-celled ovary, which forms a many-seeded 6-celled capsule or berry in fruit. Stamens 6–12, more or less united with the style; anthers adnate, extrorse.—Leaves petioled, mostly heart-shaped and entire. Seeds anatropous, with a large fleshy rhaphe, and a minute embryo in fleshy albumen. A small family of bitter-tonic or stimulant, sometimes aromatic plants.
1. Asarum. Stemless herbs. Stamens 12, with more or less distinct filaments.
2. Aristolochia. Caulescent herbs or twining shrubs. Stamens 6, the sessile anthers adnate to the stigma.