. The morphology of the central cylinder in the angiosperms [microform]. Stele (Botany); Angiosperms; Stèle (Botanique); Angiospermes. ^" ANGIOSPERMS 1 that the young that there is no lar axis. ; of P. aruilina, tissue. At a is :e /- ; r is a root, ive been formed, r in some cases soil and pursue a n'" has made a )rizontal rhizome in the axil of one e writer has seen any hundreds of and in different ; normal process, der description of ion of the young a and b are the ! two horizontal in b the foliar gap mes make their intervals, become tly overlap. For one often sees an in photograp
. The morphology of the central cylinder in the angiosperms [microform]. Stele (Botany); Angiosperms; Stèle (Botanique); Angiospermes. ^" ANGIOSPERMS 1 that the young that there is no lar axis. ; of P. aruilina, tissue. At a is :e /- ; r is a root, ive been formed, r in some cases soil and pursue a n'" has made a )rizontal rhizome in the axil of one e writer has seen any hundreds of and in different ; normal process, der description of ion of the young a and b are the ! two horizontal in b the foliar gap mes make their intervals, become tly overlap. For one often sees an in photograph 4, stelar system is nchyma becomes ntimetres further A fibro-vascular lution, and forms d in the mature Irrounded by a 5us rod described 7. Subsequently, entral wall of the y becomes nearly The two axial e leaf-traces, but ts. JEFFREY : MORPHOLOGY OF THE CENTRAL CYLINDER IN THE ANGIOSPERMS II Possibly misled by Hofmeister's older account, already referred to, Van Tieghem"* has described the large axial strands as primitive, and the strands outside as secondary cortical steles derived from these. A study of development shows that, in reality, the external .strands are primitive, as may indeed be inferred from the fact that the traces of the roots and leaves are directly attached to them even in the mature rhizome. The axial concentric strands, on the other hand, are of later origin, and are to be regarded as medullary bundles. It will probably be obvious to the reader who has followed the foregoing account and examined the accompanying photographs, that the development of P. aquilina offers little support to Van Tieghem's hypothesis' of Polystely. The writer hopes to publish in the near future, an account of the stelar development of a number of cryptogamic forms of the so-called polystelic type, in which the arrangement of the nascent fibro-vascular apparatus is identical with that found in P. aquilina. The young stelar system of the so-called polystelic type among the
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