. Comparative anatomy of the vegetative organs of the phanerogams and ferns;. Plant anatomy; Ferns. Chlorophyll. Its elements, in so far as they stand in immediate connection with the ti-acheae, approach on the one hand the latter, on the other hand the typical paren- chymatous cells in their form. This is the rule for the leaves of Monocotyledons and Dicotyledons'; the exceptional case in which even the ultimate transverse branchlets are completely enclosed by stout sclerenchymatous sheaths occurs ^OP^ rarely in thick leaves of Mono- 'PfT^li^^Sllof^f-^^.^ cotyledons, Rhapis, Vanda furva.
. Comparative anatomy of the vegetative organs of the phanerogams and ferns;. Plant anatomy; Ferns. Chlorophyll. Its elements, in so far as they stand in immediate connection with the ti-acheae, approach on the one hand the latter, on the other hand the typical paren- chymatous cells in their form. This is the rule for the leaves of Monocotyledons and Dicotyledons'; the exceptional case in which even the ultimate transverse branchlets are completely enclosed by stout sclerenchymatous sheaths occurs ^OP^ rarely in thick leaves of Mono- 'PfT^li^^Sllof^f-^^.^ cotyledons, Rhapis, Vanda furva. In the leaves of Ferns the branches of the bundles are, so far as investigated, always ensheathed by one or a few layers of elongated cells destitute of chlorophyll', of which the outermost often has the structure of an endodermis up to the immediate neighbourhood of the free ends. At the free ends themselves the rows of tracheides pass over into the chlorophyll-parenchyma, through the intervention of some elon- gated smooth-walled cells. In the. case of many ends of bundles, which according to their local position must be called pert- pheral, no essential differences from the internal ends are to be mentioned. On the other hand, the structure shows peculiarities in those numerous cases, where the bundles run to parts of the epi- dermis described in Chap. I, which are distinguished by water-pores and water-filtration, by excretion of lime, or by glandular Structure and secretion. Of the cases belonging to this series, in the first instance, the ends of the bundles in the furrows of Fern-leaves excreting water and lime (p. 106) are closely similar to the internal terminations in these leaves''. They show a knob-like swelling, in consequence of a sudden increase in the number and size of the tracheides, the latter being very short, with narrow FIG. 174.—Zea Mais. Cross-section through a feeble (lower) leaf- sheath, about z em. higher than Fig. 151, p. 331. e epidermis of the o
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Keywords: ., bookcentury1800, bookdecad, booksubjectplantanatomy, bookyear1884
