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SVENSK BOTANISK TIDSKRIFT. 1922. Bp. 16, H. 2.
ON THE GEOLOGICAL HISTORY OF THE
SCIADOPITINEAE.
A PRELIMINARY NOTE
BY
RUDOLF FLORIN.
That the genus Sciadopitys occupies a remarkably isolated posi-
tion within the Taxodineae, is emphasized by several authors as a
result of morphological, anatomical and embryological investigations.
The vegetative system is built up of long shoots and short shoots,
in which respect this genus differs from other taxodineous genera.
The peculiar short shoots, which may be characterized as sym-
phyllods or double needles, give Sciadopitys an isolated position
among all other known recent conifers. According to my own
investigations, which I propose to publish in the near future,
Sciadopitys differs from all recent gymnosperms with regard to the
structure of stomata. This structure is, according to the work of
PonscH, of great phylogenetic importance. Of the gymnosperm-
type of stomata Porscu also says: “Der Porus zeigt meist keine
Gliederung in Vorhof, Zentralspalte und Hinterhof, sondern ist sehr
niedrig, in verschiedener Höhe ziemlich gleich weit, seltener in der
Mitte schwach erweitert.“ Characteristic for the stomata of Scia-
dopitys are, however, a central pore and a “Vorhof“, bounded on
the outer side by two thin ridges or lamellae (fig. 1), which take
their origin from the two guard-cells and bend over the stomatic
aperture in a very peculiar manner. Further Sciadopitys is of
much interest with regard to embryology. Lawson says: “On the
whole the embryo of Sciadopitys is rather unique; it does not bear |
a close resemblance to either the Abietineae, Cupressineae, or Taxa-
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