. The morphology of the central cylinder in the angiosperms [microform]. Stele (Botany); Angiosperms; Stèle (Botanique); Angiospermes. ^NGIUSPRRMS )unt of the fact jusly single and ^linder is some- iws larger, and a gregated in the ;rands of paren- itute the mcdul- 1cm and phloem I, in his opinion, : bundles of De iifferent morpho- ue of the cortex, type is shut off ericycle and the ric fibre-vascular ind in the stems nccs, among the ium, and certain is and pericycle, etween the meri- sities. The frag- 3 unite around the first place merely intral cylinder is ; its pith and rays ntal tissue out
. The morphology of the central cylinder in the angiosperms [microform]. Stele (Botany); Angiosperms; Stèle (Botanique); Angiospermes. ^NGIUSPRRMS )unt of the fact jusly single and ^linder is some- iws larger, and a gregated in the ;rands of paren- itute the mcdul- 1cm and phloem I, in his opinion, : bundles of De iifferent morpho- ue of the cortex, type is shut off ericycle and the ric fibre-vascular ind in the stems nccs, among the ium, and certain is and pericycle, etween the meri- sities. The frag- 3 unite around the first place merely intral cylinder is ; its pith and rays ntal tissue outside I in certain amphi- he Cryptogams in isetum. In these wn pericycle and ilete fibro-vascular ^ by a continuous then said to be I, E. limosum and surrounded by an vaticiim and in the steles are fused to- oth outwardly and JBFFRKV : OK THE CENTRAL CVLINORR IN THE ANOIOMPERM8 5 Instead of expanding and becoming medullatcd monostclic, or pass- ing from this modification the astelic condition, the fibro-vascular axi^ may, according to Van , undergo successive bifurcations and thus become polystelic. This type of central cylinder is very prcva- lent among the vascular cryptogams, and occurs also in certain species of I'rimula and Gunnera among the Phanerogams. In a cross section of an older stem of this type, numerous concentric fibro-vascular strands are to be seen imbedded in a matrix of fundamental tissue. Ihe origin- ally separate steles of the polystelic axis, may unite, according to Van Tieghem, to form a concentric annular stele, which is described as gamo- stelic. More recently, Van Tieghem'-* has returned to the subject of the central cylinder of the Equisctace;e. In his essay on I'olystely, he the central cylinder of E. ar,>ense^ E. pratense, as niedullated monostelic; E. limosum and E. litorale as astelic, and the aerial shoot of E hiemalc as gamodesmic. Confirming an earlier research of I fitzer he recognizes that in the
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