. Flowers and their pedigrees . is distinction go the two or three other dis-tinctions which mark off the two main classes fromone another—namely, that the one has leaves withparallel veins, only one seed-leaf to the embryo, andan endogenous stem, while the other has leaves withnetted veins, two seed-leaves to the embryo, and anexogenous stem. Neverthless, in spite of such funda-mental differences, we may say that the alismas andthe buttercups really stand very close to one anotherin the order of development. When the two mainbranches of flowering plants first diverged from oneanother, the ear
. Flowers and their pedigrees . is distinction go the two or three other dis-tinctions which mark off the two main classes fromone another—namely, that the one has leaves withparallel veins, only one seed-leaf to the embryo, andan endogenous stem, while the other has leaves withnetted veins, two seed-leaves to the embryo, and anexogenous stem. Neverthless, in spite of such funda-mental differences, we may say that the alismas andthe buttercups really stand very close to one anotherin the order of development. When the two mainbranches of flowering plants first diverged from oneanother, the earliest petal-bearing form they produced 142 Flowers and their Pediorees. on one divergent branch was the alisma, or some-thing very like it ; the earliest petal-bearing formthey produced on the other divergent branch was thebuttercup, or something very like it. Hence, when-ever we have to deal with the pedigree of either greatline, the fixed historical point from which we mustneeds set out must always be the typical alismas or. a, ovaries ; 3, stamens, inner whorl ; c, stamens, outer whorl ; d, petalse, calyx-pieces. Fig. 32.—Diagram of primitive monocotyledonous flower. the typical buttercups. The accompanying diagramwill show at once the relation of parts in the simplesttrinary flowers, and will serve for comparison at alater stage of our argument with the arrangement oftheir degraded descendants, the wheats and grasses. Our own smaller alisma has a number of ovariesloosely scattered about in its centre, as in the butter- The Origin of Wheat, 143 cups, with two rows of three stamens outside them,and then a single row of three petals, followed by thecalyx or inclosing cup of three green pieces. Itsclose ally the water-plantain, however, shows signs ofsome advance towards the typical lily form in thearrangement of its ovaries in a single ring, oftenloosely divisible into three sets. And in the prettypink flowering rush (not of course a rush at all in thescientific sense) the
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectbotany, bookyear1884
