The Essentials of BotanyHolt, 1896 - 356 páginas |
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Términos y frases comunes
alcohol alternate leaves antherids antherozoids anthers archegones asexual asexual reproduction branches breathing-pores buds calyx carbon carpels carpogone cell-wall cells chlorophyll chloroplasts color common composed compound conidia corolla corolla-lobes cotyledons develop Dicotyledons disk elongated embryo endosperm epidermis examine Family ferns fertilization fibro-vascular bundles fibrous tissue filaments Flora flowering plants fruit fungi germ-cell germination green grow growth Herbs higher plants hypha Indian corn insects layer leaf Liverwort lobed longitudinal sections Magnified mass mosses Mount oögone ovary ovules parasitic perianth petals pistil placenta plant-body pollen portion Practical Studies.-(a produced prothallium protoplasm reproduction resting spore root saprophytes seeds sepals sexual organs sexual plant showing shrubs Shrubs and trees shrubs with alternate sieve-tissue soft tissue species specimens spiral spore-cases spore-fruit spore-sacs stamens starch stem stigma structure SUB-ORDER surface thickened thin cross-sections tion tracheary Trees and shrubs trichomes tube usually vegetative vessels walls whorls young zoospores
Pasajes populares
Página 108 - ... to sweep small ellipses or cir-cles, as far as the pressure of the surrounding earth permitted. All this astonishing amount of movement has been going on year after year since the time when, as a seedling, the tree first emerged from the ground.
Página 108 - If we look, for instance, at a great acacia tree, we may feel assured that every one of the innumerable growing shoots is constantly describing small ellipses ; as is each petiole, sub-petiole, and leaflet.
Página 113 - ... twigs of cottonwoods and some willows. In all these cases the essential feature is the separation from the parent plant of one or more living cells, which continue to grow, eventually producing a plant like the parent. In marked contrast to the foregoing are the various modifications of the sexual reproductive process, in which the essential feature is the union of two cells in the formation of the first cell of the new plant. In the simplest cases two apparently similar cells fuse into one,...
Página 336 - ... opposite leaves; stamens usually double the number of petals ; pistil 2- to many-celled, free or adherent to the calyx-tube; ovules minute, numerous, on axile or parietal placentae.