. The origin of a land flora, a theory based upon the facts of alternation. Plant morphology. 4io SPHENOPHYLLALES. P. PSILOTACEAE unbranched, though occasionally a dichotomy may be observed (Fig. 226 a). The aerial shoots differ from the rhizomes in bearing appendages : first, small scale-like bodies are produced, but higher up they enlarge gradually, till the condition of the fully-formed foliage leaf is attained : this is about half an inch long, and flattened in a vertical plane. The basal vegetative region is continued directly into the fertile region : here the distinctive feature is the
. The origin of a land flora, a theory based upon the facts of alternation. Plant morphology. 4io SPHENOPHYLLALES. P. PSILOTACEAE unbranched, though occasionally a dichotomy may be observed (Fig. 226 a). The aerial shoots differ from the rhizomes in bearing appendages : first, small scale-like bodies are produced, but higher up they enlarge gradually, till the condition of the fully-formed foliage leaf is attained : this is about half an inch long, and flattened in a vertical plane. The basal vegetative region is continued directly into the fertile region : here the distinctive feature is the forked sporophyll,1 which bears the sporangiophore seated at the fork, and on its adaxial surface: each sporangiophore supports two large and confluent sporangia (Fig. 226 b, c). The disposition of the leaves upon the mature axis is irregularly alternate, and this appears in transverse section of the apical bud (Fig. 227) : here the axis shows. 1-1. ;. 227. Transverse section through a spor- angiferous bud of Tmesipleris. ax~ axis. y=foliage leaves. 1= lateral lobes. .ri' = synangia. X Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Bower, F. O. (Frederick Orpen), 1855-1948. London, Macmillan and Co. , Ltd.
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Keywords: ., bookcentury1900, bookdecade1900, bookpublisherlondonmacmillanand
