. Nature and development of plants. Botany. 336 STRUCTURE OF EQUISETUM and take little or no part in photosynthesis. These scale leaves are arranged with great regularity at the nodes of the stem, and owing to their close association they grow together, forming a papery sheath with teeth-like points about the stem (Fig. 232, I). It is noteworthy that in allied fossil forms large chlorophyll- bearing leaves occurred. The stems are of two kinds, subterranean rhizomes that branch. Fig. 233. Cross-section of a portion ot the stem showing its grooved character and stereome confined to the ridges: a
. Nature and development of plants. Botany. 336 STRUCTURE OF EQUISETUM and take little or no part in photosynthesis. These scale leaves are arranged with great regularity at the nodes of the stem, and owing to their close association they grow together, forming a papery sheath with teeth-like points about the stem (Fig. 232, I). It is noteworthy that in allied fossil forms large chlorophyll- bearing leaves occurred. The stems are of two kinds, subterranean rhizomes that branch. Fig. 233. Cross-section of a portion ot the stem showing its grooved character and stereome confined to the ridges: a, air spaces; e, endodermis, inside of which are shown three bundles. extensively through the soil, and aerial stems that arise as branches from the rhizomes. The aerial stem is simple or branched and is characterized by nodes made conspicuous by the sheathing teeth-like leaves and strongly furrowed internodes. In such species as branch, these organs originate with great regular- ity in the axils of the leaves and perforating the sheathing leaves produce a bushy symmetry that caused the name of Equisetum or horsetail to be applied to these plants. The epidermal cells are hard and rough, owing to the abundant deposit of silica in the cell walls. For this reason certain species were used in early times for scouring purposes and so they became pojjularly known as scouring rushes. Complete silicious casts of the epidermal. 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 Curtis, Carlton Clarence, 1864-1945. New York, H. Holt
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Keywords: ., bookcentury1900, bookdecade1910, bookpublisher, booksubjectbotany
