. The classification of flowering plants. verted to thejuvenile character; in other cases the juvenile occurs along withthe ordinary form and the foliage is heteromorphic. In the Cuptessineae the leaves are often heteromorphic, twoor more different forms occurring on the same shoot. This isdue in part to the appearance of the spreading narrow flat andpointed primordial leaves in greater or less profusion, in additionto the characteristic ^dpressed small scale-like adult leaves, whichon flattened shoots may also be different in form according totheir position on the flank or face. The scale-lik
. The classification of flowering plants. verted to thejuvenile character; in other cases the juvenile occurs along withthe ordinary form and the foliage is heteromorphic. In the Cuptessineae the leaves are often heteromorphic, twoor more different forms occurring on the same shoot. This isdue in part to the appearance of the spreading narrow flat andpointed primordial leaves in greater or less profusion, in additionto the characteristic ^dpressed small scale-like adult leaves, whichon flattened shoots may also be different in form according totheir position on the flank or face. The scale-like leaves are concrescent with the axis at their base, a phenomenon dueto a common growth of the axis and the leaf-base, and not to Ill] CONIFERAE 81 a subsequent union. In some cases all or a large proportionof the adult leaves are concrescent, as in Cupressus Macnahiana(fig. 21), or the Australian genus Gallitris. In the flattenedbranch-systems of species of Lihocedrus (fig. 19, B), CupressusLawsoniana and others, IS muchapparent in the. concrescencemore lateral than in themedian leaves. Thespecies of Jimijjerus fallinto two sets accordingas the leaves are ho-momorphic (e. g. , fig. 22), andheteromorphic ( , fig. 23) re-spectivel}^ The leaves of theLarch fall in the firstyear, as also do thoseof Taxodium distichumand Glyptostrohus to-gether with the annualshoots of limited dwarf-shoots of thePines with their leaveslast several years beforedropping, and the sameapplies to the shortshoots of Araucaria ex-celsa and its allies. Thebroader-based leaveslike those of the ChiliPine {Araucaria im-bricata) live ten yearsor more, and thengradually dry up andperish. The phyllotaxy is sometimes whorled, sometimes spiral. Theformer arrangement characterises the Cupressineae, and occurs R. 6 Fig. 19. A. Young plant of Lihocedrusdecurrens shewing cotyledons (c), primordialleaves (pr) and transitional leaves (tr). B. Branchshewing adult foliage {ad). From Ve
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectbotany, bookyear1904
