1. In the present paper the writer studies on the vascular course in the cone scales of
Sciadopitys verticillata SIEB. et ZUCC.,
Cryptomeria japonica DON,
Cunninghamia lanceolata HOOKER and
Taiwania cryptomerioides HAYATA to define the systematic position in the Taxodiaceae.
2. In
Sciadopitys verticillata, four bundles leave the central cylinder of the axis, three of which from the top of the cylinder gap supply the seminiferous scale, and one from the base of the gap the bract. On entering the scale, the bract bundle remains undivided and two of the three scale bundles (the middle one remaining undivided) throw off several branches. These branches bend back, about two-thirds of the way up the scale, towards the place of insertion of the ovules.
3. In
Cryptomeria japonica, a single bundle arises from the axis as a small cylinder. It is immediately separated into three or four bundles, the undermost one supplying the bract and the upper two or three the seminiferous scale. For a while, the bract bundle is undivided, but the scale bundles divide into six or seven. About one-thirds of the way up the scale, the bract bundle also begins to branch, as well as the scale bundles. Finally, the branches of the scale and bract bundles arrange in an irregular ellipse in the cone scale.
4. In
Cunninghamia lanceolata, vascular supplies to bract and scale leave the central cylinder as one bundle. Soon, it throws off a weak bundle inverting itself which supplies an ovule and divides into two branches about one half of the way up the scale. Meanwhile, the beginning bundle is divided into three, then into five or six about one half of the way up the scale; at the same time, two small bundles inverting themselves arise each from the outermost bundles and supply the ovules. In the result, three undeveloped seminiferous bundles, so to speak, live upon the highly developed bract bundles.
5. In
Taiwania cryptomerioides, a single bundle is given off from the axis as in
Cunninghamia lanceolata. It is divided into three, then into five, about two-thirds of the way up the scale; at this time, two weak bundles inverting themselves arise each from the outermost buudles and supply the ovules. In this genus, two seminiferous bundles are developed so much the worse than those in
Cunninghamia, and are completely fused into the bract bundles.
6. As far as the writer deals with the vascular course of the cone scales, he comes to these conclusions.
a)
Sciadopitys is distinctly different from the other genera, but is rather near to Pinaceae-Abietoideae (PILGER). It is naturally accepted that it represents an independent family “Sciadopityaceae.”
b)
Cryptomeria together with
Taxodium and
Sequoia represents a family “Taxodiaceae” in having the similar structure of the cone scales.
c)
Cunninghamia resembles
Athrotaxis very much in the vascular course, and these two genera may represent a family “Cunninghamiaceae.”
d)
Taiwania is a peculiar genus different from the other genera in having a cone scale with two scale bundles completely fused into the bract bundles, and then represents a distinct family “Taiwaniaceae.”
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