. Flowers of the field. Botany. POND-WEED FAMILY 517 oblong, wavy, toothed, 3-nerved, spreading, and recurved ; stipules small, blunt, falling off; flowers 6—8 in a loose spike on a taper- ing stalk; carpels with a long beak.—Ditches; common.—Fl. June—August. Perennial. ** Leaves nearly opposite, involute, exstipulate 18. P. densus (Opposite-leaved Pond-weed). — Stem slender, brittle, dichotomously branched ; leaves all sub- mersed, embracing the stem, ovate, toothed, pellucid, 3—5-herved, close - set, recurred ; flowers few, in very short- stalked spikes ; carpels with short, recurved beaks.
. Flowers of the field. Botany. POND-WEED FAMILY 517 oblong, wavy, toothed, 3-nerved, spreading, and recurved ; stipules small, blunt, falling off; flowers 6—8 in a loose spike on a taper- ing stalk; carpels with a long beak.—Ditches; common.—Fl. June—August. Perennial. ** Leaves nearly opposite, involute, exstipulate 18. P. densus (Opposite-leaved Pond-weed). — Stem slender, brittle, dichotomously branched ; leaves all sub- mersed, embracing the stem, ovate, toothed, pellucid, 3—5-herved, close - set, recurred ; flowers few, in very short- stalked spikes ; carpels with short, recurved beaks. — Ditches and ponds ; common. — TH. June — September. Pe- rennial. *** Leaves all similar, strap-shaped, with flat margins and free stipules 19. P. compressus. — Stem compressed, wing- ed ; leaves 4 — to in., acute, 3—5-nerved ; sti- pules large, acute ; flowers many, in cylindric, long- stalked spikes ; carpels compressed, 3-ribbed.— Ditches; local.—Fl. July, August. Perennial. 20. P. acutifoliiis.—Stem compressed, narrower than in the preceding ; leaves much as in the preceding but. shorter and with narrower stipules; flowers in a very short oval, short-stalked spike ; carpels compressed, with a recurved beak.—Lakes and ditches ; rare.—Fl. June—August. Perennial. 21. P. oZ'/«5zyf//«5 (Grassy Pond-weed).—Stein slender, 4-angled, much branched ; leaves sessile, linear, obtuse, dark green, opaque, 3-nerved ; stipules broad, blunt; flowers few, in a dense, oval,. rOTAMOG^TOX D^NSL'S {O/'/'OSi/L-l'jaZ'cd F^vrd-zccwf).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Johns, C. A. (Charles Alexander), 1811-1874. London : Society for Promoting Christian Knowledge
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1911
