. The anatomy of woody plants. Botany -- Anatomy. THE MONOCOTYLEDONS 411 lateral ones are weak and degenerate. The fibrovascular bundles of the leaf in monocotyledons are ordinarily very numerous and consequently enter the stem in large numbers at the nodes. The large number of foliar bundles passing from the base of the mono- cotyledonous leaf into the stem is correlated with a high degree of assimilative efficiency which finds expression in a proportion of seed production which has scarcely ever been reached in her- baceous dicotyledons. In many of the cereals, for example, the relative weig
. The anatomy of woody plants. Botany -- Anatomy. THE MONOCOTYLEDONS 411 lateral ones are weak and degenerate. The fibrovascular bundles of the leaf in monocotyledons are ordinarily very numerous and consequently enter the stem in large numbers at the nodes. The large number of foliar bundles passing from the base of the mono- cotyledonous leaf into the stem is correlated with a high degree of assimilative efficiency which finds expression in a proportion of seed production which has scarcely ever been reached in her- baceous dicotyledons. In many of the cereals, for example, the relative weight of the seed to that of the whole plant very frequently reaches over 30 per cent. The high efficiency of the group, both from the standpoint of production of assimilates and from that of the formation of seeds, naturally puts it in a unique position in supplying important food plants. In many cases, particularly in the grasses and sedges, cam- bial activity, absent in the stem and root, is often retained in the basal or sheath region of the leaf or sometimes in relation to the node in the stem. The capacity which grasses manifest for erecting their stems after "lodging" is to some extent the result of the presence of a persistent cambium in the nodal region, either in the base of the leaf or in relation to the stem itself. Fig. 285 illustrates such cambial activity in the case of Avena barbata. It is permissible to view this cambial activity as a persistence of an ancestral character, particularly as it is often found to be present in monocotyledonous seedlings in the lower region of the epicotyl or primitive stem. The organization of the closed fibrovascular bundles of the monocotyledons is in many cases collateral and, as the descriptive term implies, exhibits no indication of cambial activity. The collateral type of fibrovascular strand is characteristic of the leaf, since that organ, here as elsewhere, is conservative in its FIG. 285.—Transverse se
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