. The natural history of plants, their forms, growth, reproduction, and distribution;. Botany. 662 THE SUBDIVISIONS OF THE VEGETABLE KINGDOM. stipe, and a flat, expanded leaf, deeply lobed like a hand. It is often met with two metres in length. The leaf is of a leathery consistency, and the flattened or cylin- drical stalk has a wide parenchymatous cortex and central "medulla", in which run curious tubes (the "trumpet hyphse") which swell out at intervals, the swelling being traversed in a transverse direction by a delicate sieve-plate. The stem possesses a peripheral cambi
. The natural history of plants, their forms, growth, reproduction, and distribution;. Botany. 662 THE SUBDIVISIONS OF THE VEGETABLE KINGDOM. stipe, and a flat, expanded leaf, deeply lobed like a hand. It is often met with two metres in length. The leaf is of a leathery consistency, and the flattened or cylin- drical stalk has a wide parenchymatous cortex and central "medulla", in which run curious tubes (the "trumpet hyphse") which swell out at intervals, the swelling being traversed in a transverse direction by a delicate sieve-plate. The stem possesses a peripheral cambium-like zone, which adds each year a new zone of tissue to the cortex. The stems, which are sometimes found much thicker than one's. Fig. 376.—LamlnariacesB, with perforated fronds. 1 Agarum Gmelini (after Biocreux). 2 ThallasiophyUum dathrum (after Poatels and Buprecht). Both much reduced. thumb, show in section a series of rings, reminding one of the annual rings of a dicotyledonous stem. A long ribbon-like form, L. saccharina, is also common on our shores. In other forms the frond is branched and often curiously appendaged at the base. In the two genera represented in the accompanying illustration (figs. 3761 and 376 ^) Agarum (from the North Atlantic) has a simple, Thallasiophyllum (North Pacific) a compound frond. In both the fronds are perforated or fenestrated. Lessonia (Southern Pacific) attains to tree-like dimensions and is much branched; It has a stem as thick as a man's thigh. But the two most impressive genera are Macrocystis and Nereocystis. The former, which occurs throughout the southern oceans and on the western coast of N. America, consists of a long stalk, sometimes attammg a length of 300 metres, but in thickness not exceeding a penholder To. 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 wor
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectbotany, bookyear1895
