. The classification of flowering plants. Plants. Ill] CONIFERAE 85 communicating by pits with the sieve-tubes, and known as albuminous cells. They probably correspond functionally with the companion-cells of Angiosperms. The tracheides formed towards the end of each season are much narrower and have much thicker walls than those formed in the spring; this contrast between spring and autumn wood causes the characteristic demarcation of annual rings. Schizo- genously formed resin-passages are common in the cortex, and occur also in the primary and secondary wood, and sometimes in the larger med
. The classification of flowering plants. Plants. Ill] CONIFERAE 85 communicating by pits with the sieve-tubes, and known as albuminous cells. They probably correspond functionally with the companion-cells of Angiosperms. The tracheides formed towards the end of each season are much narrower and have much thicker walls than those formed in the spring; this contrast between spring and autumn wood causes the characteristic demarcation of annual rings. Schizo- genously formed resin-passages are common in the cortex, and occur also in the primary and secondary wood, and sometimes in the larger medullary rays as in Pinus or in the phloem as in Fig. 24. Transverse section of leaf of Tsuga Brunoniana x 30, shewing thickened epidermis, hypoderma confined to the lateral margin, palisade arrangement of upper mesophyll, a single vascular bundle (/) and a median resin-canal (r). From Veitch. The anatomy of the leaf shows marked xerophy tic characters. The epidermal cells are thick-walled and strongly cuticularised, and each stoma is sunk at the bottom of a pit. Below the epi- dermis are thick-walled, strengthening bands of hypoderma. The mesophyll in the broader leaves is differentiated into. 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 Rendle, A. B. (Alfred Barton), 1865-1938. Cambridge, University press
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectplants, bookyear1904
