. The natural history of plants, their forms, growth, reproduction, and distribution;. Botany. PLANTS WITH TRAPS AND PITFALLS TO ENSNARE ANIMALS. 121. bifurcating, segments, or else only half of them are thus clothed with leaves whilst the other half bear the before-mentioned bladders. The former is the case in Utricularia'minor, the plant represented in the background of the figure on p. 120; and the latter in Utricularia Grafiana, which is drawn in the foreground. In instances of the former kind obliquely ellipsoidal bladders are to be seen on short stalks on the principal segments of the le
. The natural history of plants, their forms, growth, reproduction, and distribution;. Botany. PLANTS WITH TRAPS AND PITFALLS TO ENSNARE ANIMALS. 121. bifurcating, segments, or else only half of them are thus clothed with leaves whilst the other half bear the before-mentioned bladders. The former is the case in Utricularia'minor, the plant represented in the background of the figure on p. 120; and the latter in Utricularia Grafiana, which is drawn in the foreground. In instances of the former kind obliquely ellipsoidal bladders are to be seen on short stalks on the principal segments of the leaves, usually quite near their angles of bifurcation. In the smaller species, such as Utricularia minor, they have a diameter of about 2 mm. In individuals of the latter kind the bladders have longer stalks, and are about 5 mm. in diameter. They are always pale-green and partially trans- parent. Each bladder is somewhat flattened at the sides and exhibits a markedly convex dorsal surface and slightly curved lateral surface. An orifice, whose border is fringed with peculiar stiff tapering bristles, leads into the interior of each of these stalked bladders. The aperture has four rounded angles and is framed as it were, by a pair of lips. The under lip is strong- ly thickened, and is furnished with a solid cushion projec- ting into the inte- rior of the bladder. From the upper lip hangs a thin trans- parent, obliquely- placed valve (see fig. 18 2), the free edge of which rests upon the inner surface of the cushion before referred to, and closes the entire orifice. This valve is very elastic and yields easily to any pressure from outside. A tiny animal is able, by pressing against it, to force a way without difficulty from the nether lip into the interior of the bladder, and to slip in through the opening thus made. But as soon as the animal has got inside, and ceases to press upon the valve, its elasticity brings it back upon the under lip again. It cannot be opened by pressure fr
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectbotany, bookyear1895
