. The families of flowering plants. Plants; Phanerogams. 18 FAMILIES OF FLOWERING PLANTS. neys. The pollen, which its produced in great quantities during the flowering season, is sometimes employed in place of lycopodium spores as an absorbent powder. Family Sparganiaceae.—Bur-reed Family. This also consists of a single genus, Sparganlimi, and it was formerly included among the cat-tails. The plants possess an entirely different aspect, however; the flowers are monoecious, as in Typha, but they are borne in several globular heads on the upper branches of the stem, and not in a single terminal
. The families of flowering plants. Plants; Phanerogams. 18 FAMILIES OF FLOWERING PLANTS. neys. The pollen, which its produced in great quantities during the flowering season, is sometimes employed in place of lycopodium spores as an absorbent powder. Family Sparganiaceae.—Bur-reed Family. This also consists of a single genus, Sparganlimi, and it was formerly included among the cat-tails. The plants possess an entirely different aspect, however; the flowers are monoecious, as in Typha, but they are borne in several globular heads on the upper branches of the stem, and not in a single terminal spike. (See Fig. 13.) The fruit is hard and nutlike, much larger than that of the cat-tail, and without any intermixed bristles, while the leaves are thin and grasslike. Sparganhim contains about 8 species, natives of temperate regions; they are not known to pos- sess any economic uses. ORDER HELOBIAE. Family Naiadaceae.—Pondweed Family. About 10 genera, widely distributed, of which Potamogeton is the only one of much size or importance, containing about 50 species, 30 of which occur in the eastern United States and a large proportion of them in New Eng- land alone. SIom' streams and rather shallow ponds form the favorite haunts of these plants, whose smooth oval leaves floating on the surface of the water may be noticed in many such situa- tions. All the pondweeds are im- mersed aquatics with slender, often branching stems and small greenish flowers usually borne in spikes; they are either perfect (having the stamens and pistils in the same flower), monoecious or dioecious, in some cases wholly des- titute of floral envelopes, in others, with a perianth of four distinct segments. In this latter respect it will be seen that they are exceptional among the monocotyledons, which it will be remembered are usually distinguished by the three-. FiQ. 14.—Clasping-leaved poncJweea (Pota- mogeton perfotiatua) with enlarged Irult and section of the latter. (After Britton iind Brown,
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectplants, bookyear1900
