. The anatomy of woody plants. Botany -- Anatomy. THE LYCOPODIALES 261 of stomata, ordinarily accommodated in furrows on the lower surface of the leaf. The aeriferous structures of the blades of the leaves were continuous with air-containing radial structures in the outer and inner bark known as parichni. These are a noteworthy feature of structure in the lepidodendrids and have attracted a large amount of attention from students of the group. It should be pointed out, however, that they are by no means a unique structure, since special aerating devices are likewise found present in relation t
. The anatomy of woody plants. Botany -- Anatomy. THE LYCOPODIALES 261 of stomata, ordinarily accommodated in furrows on the lower surface of the leaf. The aeriferous structures of the blades of the leaves were continuous with air-containing radial structures in the outer and inner bark known as parichni. These are a noteworthy feature of structure in the lepidodendrids and have attracted a large amount of attention from students of the group. It should be pointed out, however, that they are by no means a unique structure, since special aerating devices are likewise found present in relation to the leaves of the Coniferales. The roots of the lepido- dendrids have been the subject of much discus- sion. Their ultimate divisions, the so-called stigmarian rootlets (Fig. 187), are character- ized by a very simple organization, since only a single group of protoxy- lem is present. The root- lets of this order divided dichotomously, as is often. FIG. 186.—Leaf trace of a lepidodendrid (after Scott). the case with those of the living Isoetes and Lyco podium. The main roots of the lepidodendroid forms are in all probability only partially known to us and present a curious type of structure. To begin with, there is a large pithlike mass around which is developed an extremely small amount of primary wood, at times so rudimen- tary as to be scarcely recognizable. The small degree of develop- ment of the primary structures and the quincuncial arrangement of the lateral rootlets of Stigmaria have led to a great deal of doubt as to their morphological nature. They have often been regarded as creeping stems or rootstocks, and this view of their nature is found even in recent literature on the subject. The mass of anatomical. 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 Jeffrey, Edward C. (Edward Charles), b
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