. Lectures on the evolution of plants. Botany; Plants. PTEBIDOPHYTA 143 peculiarity has been recently detected in one of the living species of Equisetum. Associated with some of the fossil forms there are found cones, which evidently belong with them, and resemble those of the existing Equisetum. In a few instances they have been preserved so perfectly that the inner structure can be accu- rately made out, and it is evi- dent that the tissues and spo- rangia of these plants closely resembled those of Equisetum, although most of them exhibit a degree of specialization not found in any of their
. Lectures on the evolution of plants. Botany; Plants. PTEBIDOPHYTA 143 peculiarity has been recently detected in one of the living species of Equisetum. Associated with some of the fossil forms there are found cones, which evidently belong with them, and resemble those of the existing Equisetum. In a few instances they have been preserved so perfectly that the inner structure can be accu- rately made out, and it is evi- dent that the tissues and spo- rangia of these plants closely resembled those of Equisetum, although most of them exhibit a degree of specialization not found in any of their living relatives. The Equisetineae rap- idly diminish in importance in the later geological epochs, until, as we have seen, but a single genus has survived to the pres- ent time, and this is one of the less specialized Lycopodine^ Fig. 37 (Lycopodineae). — A, part of a plant of a club- moss (LycopodHim clava- tum) with two sporan^al spikes, sp;B,a, sporophyll from the spike of L. den- droideuTti, bearing a single large sporangium, sp; C, cross-section of the stem; vb, the central vascular cylinder. The third class of Pterido- phytes, the Club-mosses, is intermediate in point of num- bers between the two already considered. There are three well-marked orders, of which the first, Lycopodi- acese, includes the common club-mosses belonging to the genus Lycopodium. The second order, Selaginel-. 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 Campbell, Douglas Houghton, 1859-1953. New York, London, The Macmillan company
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Keywords: ., bookcentury1900, bookdecade, booksubjectbotany, booksubjectplants
