Organography of plants, especially of the archegoniatae and spermaphyta . ers a feature of formation of organs that is limited to the germ-plantin Lycopodium inundatum and L. cernuum, and to the adventitiousshoots resembling those in L. inundatum. This view appears to me to beat the present time the most natural one, even though it rnay appear a heresyto the older morphology. Transition between Leaf and Shoot. I have frequently said that the behaviour of Utricularia is of specialinterest in the general consideration of the formation of organs, and I mustnow say something about it:— Lentibulari
Organography of plants, especially of the archegoniatae and spermaphyta . ers a feature of formation of organs that is limited to the germ-plantin Lycopodium inundatum and L. cernuum, and to the adventitiousshoots resembling those in L. inundatum. This view appears to me to beat the present time the most natural one, even though it rnay appear a heresyto the older morphology. Transition between Leaf and Shoot. I have frequently said that the behaviour of Utricularia is of specialinterest in the general consideration of the formation of organs, and I mustnow say something about it:— Lentibulariaceae. Utricularia belongs to the family of the Lentibu-lariaceae, all the genera of which are insectivorous. Pinguicula shows thenormal differentiation of the vegetative body of Spermophyta, namely, rootand leafy shoot. The other genera are rootless. The function of the rootin Genlisea ^ has been usurped by the highly remarkable tubes which at the ^ Goebcl, Pflanzenbiologische Schildemngen, ii (1893) ; id., Ziir Biologic von Genlisea, in Flora,Ixxvii (1893), p. 2o8-. Fig. 168. Lemna trisulca. i, segment separated andseen from below ; W^ root. 11, a like segrnent seen fromabove. For the explanation see the text. Magnified. TRANSITION BETWEEN LEAF AND SHOOT 237 same time serve as insect-traps, and they pierce the substratum just likeroots (Fig. 169). There can be no doubt that these tubes are transformedleaves. In Polypompholyx, and some few of the species of Utricularia whichlive on land, we find the following formation of organs :— Utricularia Hookeri. As anexample I shall take the WestAustralian Utricularia Hookeri ^(Fig. 170). A radial shoot pro-ceeds from the seed and ends inan inflorescence. This shoot, apartfrom the leaf-structures of theflowers and the bracts, bears thefollowing organs:— (a) foliage-lcavcs, [b) tubes (tubular leaves) whichend in insect-traps (bladders), {c) elongated, but unbranchedand non-tubular, thin structuresresembling roots, which we shallcal
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