. Botany, an elementary text for schools. Botany. 190 STUDIES IN CRYPTOGAMS. Seption throuKli ;i reoeptacle of Pnlvtricliuin coiiiiiiune, si paraphyses and autheridia propriately, "moss ; gins of the leaves roll inward, and the leaves fold closely against the stem, thus protecting the delicate assimilating tissue. The antheridia and archegonia of polytrichum are borne in groups at the ends of the branches on different plants (many mosses bear both organs on the same branch). They are surrounded by involucres of charac- teristic leaves termed iJC/'/cZ/fT^/a ov x>cri-
. Botany, an elementary text for schools. Botany. 190 STUDIES IN CRYPTOGAMS. Seption throuKli ;i reoeptacle of Pnlvtricliuin coiiiiiiune, si paraphyses and autheridia propriately, "moss ; gins of the leaves roll inward, and the leaves fold closely against the stem, thus protecting the delicate assimilating tissue. The antheridia and archegonia of polytrichum are borne in groups at the ends of the branches on different plants (many mosses bear both organs on the same branch). They are surrounded by involucres of charac- teristic leaves termed iJC/'/cZ/fT^/a ov x>cri- chcetal leaves. Multicellular hairs known as jiaraphyses are scattered among the archegonia and antheridia. The invo- Pnlvtricliuin coiiiiiiune, showing lucres with the Organs borne within them are called receptacles or, less ap- As in marchantia, the organs are very minute and must be highly magnified to be studied. The antheridia are borne in broad cup-like receptacles on the antheridial plants (Fig. 339). They are much like the antheridia of marchantia, but they stand free among the para- physes and are not sunk in cavities. At maturity they burst and allow the sperm-cells or spennat- ozoids to escape. In polytrichum when the re- ceptacles have fulfilled their function the stem continues to grow from the center of the cup (Fig. 340, m). The ai'chegonia are borne in other receptacles on different plants. They are like the archegonia of marehantia'except that they stand erect on the end of the branch. The sporogonium which develops from the fertilized egg is shown in Fig. 340, a, b. It consists of a long, brown stalk bearing the spore-case at its summit. The base of the stalk is embedded in the end of the moss stem by which it is nourished. The capsule is entirely inclosed by a hairy cap, the cali/ptra, b. The calyptra is really the remnant of the archegonium, which, for a time, increases in size to accommodate. Please note that these images are extracted from scanned page ima
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Keywords: ., bookauthorbai, bookcentury1900, bookdecade1900, booksubjectbotany
