. Text-book of botany, morphological and physiological. Botany. FILICINEM, 475 central vascular body, and continually producing new layers of parenchyma on the outside. This takes place especially in two or three directions, so that two or three corresponding masses of tissue are formed, slowly dying off on the outside, between which lie as many deep furrows meeting on the under surface of the stem. From these a large number of roots are produced in rows in acropetal succession. In the Selaginellese the stem remains slender, but lengthens rapidly, branching profusely, and forms distinct intern
. Text-book of botany, morphological and physiological. Botany. FILICINEM, 475 central vascular body, and continually producing new layers of parenchyma on the outside. This takes place especially in two or three directions, so that two or three corresponding masses of tissue are formed, slowly dying off on the outside, between which lie as many deep furrows meeting on the under surface of the stem. From these a large number of roots are produced in rows in acropetal succession. In the Selaginellese the stem remains slender, but lengthens rapidly, branching profusely, and forms distinct internodes. The end of the stem rises above the youngest leaves as a slender cone. In Selaginella a tendency prevails to sympodial scorpioid development of the branches which not unfrequently leads to the system of abundantly branched shoots developed bilaterally in one plane attaining a definite outline, and a corresponding resemblance to a compoundly pinnate leaf. In con- sequence of the small size of the leaves in this genus, the general habit is mainly dependent on the development of the systems of branches. The main shoots which result from the sympo- dial development of the branches may creep like rhizomes, may grow obliquely upwards, may climb, or may form the stems of arborescent and fruticose plants. In all cases the repeated branchings take place in one plane, for the bilateral symmetry which is so marked in the position of the branches and in the phyllotaxis already exists in the growing point. The Leaves are always simple, unbranched, penetrated by only a single fibro* vascular bundle, terminating in a simple point, and ending, in Selaginella, in a fine awn. The largest leaves Occur in Isoeles, where they attain \ length of from 4 to 60 cm. They are in this case divided into a basal part or sheath, and an upper part or lamina. The sheath does not entirely em- brace the stem, but rises in a somewhat trian- gular form from a very broad insertion, and is acuminate; it is con
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectbotany, bookyear1882
