. Studies in fossil botany . Paleobotany. 208 STUDIES IN FOSSIL BOTANY marked longitudinal seriation of' the soars affords, in typical cases, the most obvious distinction from the sculpturing of Lepidodendron. The scars are not always seated on distinct leaf-cushions, or if such cushions are present, they are not much larger than the scars them- selves (Fig. 86). The individual leaf-scar has, as a rule, an approximately hexagonal outline, with the angles more or less rounded (see Figs. 86-89). The form. Fig. 87.—Sigillaria mamillaris (Rhytidolepis type). Surface of stem, showing vertical ribs
. Studies in fossil botany . Paleobotany. 208 STUDIES IN FOSSIL BOTANY marked longitudinal seriation of' the soars affords, in typical cases, the most obvious distinction from the sculpturing of Lepidodendron. The scars are not always seated on distinct leaf-cushions, or if such cushions are present, they are not much larger than the scars them- selves (Fig. 86). The individual leaf-scar has, as a rule, an approximately hexagonal outline, with the angles more or less rounded (see Figs. 86-89). The form. Fig. 87.—Sigillaria mamillaris (Rhytidolepis type). Surface of stem, showing vertical ribs with leaf-scars"(/.j.) and scars of the cones (). Nat. size. After Zeiller. of the scar varies much, not only in different species, but on different parts of the same stem ; as the stem increased in diameter with age, the scars not only became more widely separated, but were also them- selves stretched out in the horizontal direction. The prints on the scar are essentially similar to those of Lepidodendron, and are here also three in number, forming a transverse row, usually a little above the centre of the scar (see Fig. 88). The middle print,. 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 Scott, Dukinfield Henry, 1854-1934. London, A. and C. Black
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