. Lessons with plants. Suggestions for seeing and interpreting some of the common forms of vegetation. Fig. of spruce pine. 376. We have now discerned two most impor-tant characters in plants,—the fact that some plantsbear their ovules (and seeds) in a closed receptacleor ovary, whereas others bear naked seeds. Thesecharacters enable us to divide all flowering plantsinto two great classes, the angiosperms and thegymnosperms. The angiosperms, or those having apericarp, comprise the greater part of our com-mon plants, nearly all those, in fact, which wehave studied up to this point. The
. Lessons with plants. Suggestions for seeing and interpreting some of the common forms of vegetation. Fig. of spruce pine. 376. We have now discerned two most impor-tant characters in plants,—the fact that some plantsbear their ovules (and seeds) in a closed receptacleor ovary, whereas others bear naked seeds. Thesecharacters enable us to divide all flowering plantsinto two great classes, the angiosperms and thegymnosperms. The angiosperms, or those having apericarp, comprise the greater part of our com-mon plants, nearly all those, in fact, which wehave studied up to this point. The gymnosperms, 310 LESSONS WITH PLANTS bearing naked ovules, comprise the pines, spruces,firs, cedars, yews, junipers, cypresses, ginkgos,and the Fig. overgrown by the branch. 376a. Far the larger part of flowering or seed-bearing plants(or the spennatophyta) are angiosperms. The gymnospenns are very old types, geologically con-sidered. They comprisesuch plants as the pines,spruces (and all the Conif-ers or cone-bearing plants),cedars, yews, cypresses andginkgo,—the last cultivatedas an ornamental tree fromChina and Japan. Thereare various fundamentaldifferences between the an-giosperms and the gymno-sperms, but they are chieflysuch as the pupil can un-derstand only when hetakes up the study of com-parative anatomy and morphology; we cannot, therefore, give thistype of plants adequate treatment in this book. 3766. Botanists are not agreed as to the morphology of thecone of the gymnosperms. Some consider that the ovule-scalerepresents an open carpel. Others think that this scale representsa placenta, and that the subtending bract is homologous with a car-pel. Others accept neither view. Suggestions.—The pupil knows
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Keywords: ., bookauthorbai, bookcentury1900, bookdecade1900, booksubjectbotany
