. The morphology of the central cylinder in the angiosperms [microform]. Stele (Botany); Angiosperms; Stèle (Botanique); Angiospermes. 11 *f: - 14 JEFFREY ; MORPHOLOGY OF THE CENTRAL CYLINDER IN THE ANCIOSPERMS cycle in the young fibro-vascular axis o{ Pteris aquilina (photograph I, plate 7). After six or more leaf-traces have been given off, the stelar tube encloses a core of fundamental tissue. The internal face of the young stelar tube is at first devoid of phloem and it is only subsequently that it appears, thus recalling the state of affairs described by Gwynne- Vaughan in P. japonica and
. The morphology of the central cylinder in the angiosperms [microform]. Stele (Botany); Angiosperms; Stèle (Botanique); Angiospermes. 11 *f: - 14 JEFFREY ; MORPHOLOGY OF THE CENTRAL CYLINDER IN THE ANCIOSPERMS cycle in the young fibro-vascular axis o{ Pteris aquilina (photograph I, plate 7). After six or more leaf-traces have been given off, the stelar tube encloses a core of fundamental tissue. The internal face of the young stelar tube is at first devoid of phloem and it is only subsequently that it appears, thus recalling the state of affairs described by Gwynne- Vaughan in P. japonica and P. involiicrata. At this stage the stelar tube would be described in accordance with Van Tieghem's terminology as gamodesmic (gamomeristelic): collateral strands occur even in the old stem ; such a strand is figured by ;' Photograph 8, plate 8, shows a transverse section of the stelar system of this species at a region where the internal phloem has already made its appearance. At r", a root is being given off; ^* is a radical stele which has already made its exit from the central cylinder ; /' and /- are foliar gaps ; oppo- site l> may be seen its corresponding leaf-trace. Photograph 9, plate 8, is similarly lettered. In this case the leaf-traces corresponding to two foliar gaps are to be seen. The stelar system of P. farinosa is thus from the first, a tube, including primarily only a pericycle, and then fundamental tissue as well. The tube is, in the beginning, collateral, but becomes subsequently bicollateral through the appearance of inter- nal phloem. The stelar tube has gaps in its walls above the points of exit of leaf-traces. No such gaps occur opposite the outgoing radical strands. The writer's examination of the development of P. farinosa leads to results similar to those obtained by Gwynne-Vaughan in the case of other so-called polystelic species of this genus, viz., I. That the stelar system in the young plant does not successively bifurcate,
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