. The morphology of the central cylinder in the angiosperms [microform]. Stele (Botany); Angiosperms; Stèle (Botanique); Angiospermes. JRPFRBV : Of TIIK CRNTRAI. CVLINnRR IN Tlllt ANOIOHPrRMS the younj( sporophyte. If any (lci)endc«nce is to be placed on ontogenetic results, it would appear that the primitive type of cauline stelar arrari^'cment in the Ktiuisetaceie, is not one in which the bundles are surrounded by individual endoderinal sheaths, but is, on the c(jnlrary, that designated by Van 'ricghcm as gamodesmic. The appropriateness of this term, as describing the condition
. The morphology of the central cylinder in the angiosperms [microform]. Stele (Botany); Angiosperms; Stèle (Botanique); Angiospermes. JRPFRBV : Of TIIK CRNTRAI. CVLINnRR IN Tlllt ANOIOHPrRMS the younj( sporophyte. If any (lci)endc«nce is to be placed on ontogenetic results, it would appear that the primitive type of cauline stelar arrari^'cment in the Ktiuisetaceie, is not one in which the bundles are surrounded by individual endoderinal sheaths, but is, on the c(jnlrary, that designated by Van 'ricghcm as gamodesmic. The appropriateness of this term, as describing the conditions present in the young stelar system of this group, will be discussed subsequently. Van Tieghem' has recently re-examined the central cylinder of the Ophioglossaceic, as a result of the discovery made by I'oirault" of the occurrenccof an internal endodermisin the _>'tf«;/^'-stelar system of several species of Hotrychiuin and Ophioglossum. I le confirms I'oirault's results and describes the distribution of the endodermis in the young central cylinder of /Mryc/u'um Ltotaria. The stelar system is tubular, and above the point of origin of the first lcaf-tracehasaninternal,aswellasanextcrnal, endodermis. The inner one rapidly disappears in the older region of the young stem. A similar state of aflfairs occurs in Ophioglossum vuh^a- turn, although in this case, the stelar tube becomes quickly broken into separate strands on account of the (jverlapping of the foliar gaps. The endodermis in this species also disappears in the older region of the stem. I'oirault*' has described a somewhat persistent /«/^/'«n:/endoder- mis in O. Bcrgianum, O. capense, and O. ellipticum. Quite recently an internal endodermal layer has been described by Farmer' as occurring in the interesting genus Helminthostachys. His own observations, to- gether with those of Poirault, lead Van Tieghem to the conclusion that the cauline stelar system of the Ophioglossacea^ is, above the exit of the first le
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