. The origin of a land flora, a theory based upon the facts of alternation. Plant morphology. 1-1. ;. 227. Transverse section through a spor- angiferous bud of Tmesipleris. ax~ axis. y=foliage leaves. 1= lateral lobes. .ri' = synangia. X Tmesipteris tamiensis, various unusual forms of sporophyll and sporangiophore; in i. the syn- angium is abortive ; in ii. and iii. one loculus is abortive ; others show a larger number of loculi than two ; others again, right and left on the lower row, show a single loculus, the septum being imperfect, or absent. a very irregular outline owing to the decu
. The origin of a land flora, a theory based upon the facts of alternation. Plant morphology. 1-1. ;. 227. Transverse section through a spor- angiferous bud of Tmesipleris. ax~ axis. y=foliage leaves. 1= lateral lobes. .ri' = synangia. X Tmesipteris tamiensis, various unusual forms of sporophyll and sporangiophore; in i. the syn- angium is abortive ; in ii. and iii. one loculus is abortive ; others show a larger number of loculi than two ; others again, right and left on the lower row, show a single loculus, the septum being imperfect, or absent. a very irregular outline owing to the decurrent bases of the appendages: it is also apparent that these are alternate: it may also be noted that in the case figured three foliage leaves (f) are inserted above the three sporophylls (/, sy, /). The fertile region forms a very lax strobilus, in which the following features may be noticed. It does not differ markedly from the vegetative region in the size of the parts which it bears : it is not composed exclusively of sporophylls, but foliage leaves of the usual type may be interspersed 'The terminology here used is thai of Scott [{Studies, p. 479). I regret having in 1893 (Studies, part i.) used the term sporangiophore in a wider sense than here, so as to include the bifid sporophyll itself. Such an extension of the term obscures the natural comparisons not only with the Sphenophylleae, but also with other sporangio- phoric types. It is best to restrict the use of the word in the Psilotaceae to the body borne by the bifid sporophyll, often designated also the synangium. The various opinions previously held as to the morphology of these appendages need not be discussed again here. It wall suffice to refer to my Studies, i., p. 539, where they have been considered at some length, with references to the literature relating to ihem. See also Lignier, Bull. Sol. Linn, de Normandie, 1904, p. 95,. and Please note that these images are extracted from scanned page image
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