The principles of biology . THE MORPHOLOGICAL COMPOSITION OF PLANTS. 23. the edges are distributed very much, at random, and are byno means specific in their shapes. A considerable advance isdisplayed by Phyllophora rubens, Fig. 39. Here the frond,primary, secondary, or tertiary, betrays some approach to-wards regularity in both form and size; by which, as also byits partially-developed mid-rib, there is estabhshed a moremarked individuality; and at the same time, the growth ofthe secondary Jfronds no longer occurs anywhere on the edge,in the same plane as the parent frond, but from the surfac
The principles of biology . THE MORPHOLOGICAL COMPOSITION OF PLANTS. 23. the edges are distributed very much, at random, and are byno means specific in their shapes. A considerable advance isdisplayed by Phyllophora rubens, Fig. 39. Here the frond,primary, secondary, or tertiary, betrays some approach to-wards regularity in both form and size; by which, as also byits partially-developed mid-rib, there is estabhshed a moremarked individuality; and at the same time, the growth ofthe secondary Jfronds no longer occurs anywhere on the edge,in the same plane as the parent frond, but from the surfaceat specific places. Delesseria sanguinea, Fig. 40, illustratesa much more definite arrangement of the same kind. Thefronds of this plant, quite regularly shaped, have their partsdecidedly subordinated to the whole ; and from their mid-ribs grow other fronds, which are just Uke them. Each ofthese fronds is an organized group of those morphologicalunits which we distinguish • as aggregates of the first in this case, two or more such aggregates of the second
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectbiology, bookyear1864
