作 者 ：Hu Yu-Shi, Ma Rui-Jun
期 刊 ：植物分类学报 1989年 2期
关键词：台湾杉属秃杉解剖学系统位置；
Keywords:Taiwania, Taiwania flousiana, anatomy, systematic position,
Abstract:
Taiwania Hayata contains two species: T.flousiana Gaussen and T. cryptomerioides
Hayata, both endemic to China.
T. flousiana was investigated with both light and scanning electron microscopes in respect
to shoot apex, external and internal surfaces of leaf cuticle, primary leaf, juvenal and mature
leaves, young stem, secondary phloem and wood of stem, etc,
It is shown that the shoot apex consists of the following five regions: (1) the apical initials;
(2) the protoderm, (3) the subapical moher cells;. (4) the peripheral meristem, and (5) the
pith mother cells. The periclinal and anticlinal division of the apical initials takes place with
approximately equal frequency.
The juvenal leaf is nearly triangular or crescent-shaped in cross section and belongs to
the leaf type II. The mature leaf is quadrangular in cross section (the leaf type I). There are
a progressive series of changes in size and shape of the leaf cross section. The stoma of the ma-
ture leaf is amphicyclic and occasionally tricyclic. The crystals in the juvenal leaf cuticle are
more abundant than those in the mature leaf cuticle. The transfusion tissue conforms to the
Cupressus type. The structure of juvenal leaf is the nearest to that in Cunninghamia unicana-
liculata D. Y. Wang et H. L. Liu, while the mature leaf is similar to that of the Cryptomeria.
Sclerenchymatous cells of the hypodermis in the young stem comprise simple layers and are
arranged discontinuously. No primary fibers are found in the primary phloem. Medullary
sheath is present between the primary xylem and the pith. There are some sclereids in the pith.
The secondary phloem of the stem consists of regularly alternate tangential layers of cells
in such a sequence: sieve cells, phloem parenchyma cells, sieve cells, phloem fibers, sieve cells.
The phloem fiber may be divided into thick-walled and thin-walled phloem fiber. The cry-
stals of calcium oxalate in the radial walls of sieve cells are abundant. Homogeneous phloem
rays are uniseriate or partly biseriate, 1-48 (2-13) cells high, and of 26-31 strips per square
mm.
Growth rings of the wood in Taiwania are distinct. The bordered pits on the radial walls
of early wood tracheids are usually uniseriate, occasionally paired and opposite pitting. Wood
parenchyma is present, and its cells contain brown resin substances. Their end walls are smooth,
lacking nodular thickenings. Wood rays are homogeneous. Cross-field pits are cupressoid. Resin
canals are absent.
Based on the anatomy of Taiwania and comparison with the other genera of Taxodiaceae,
the authors consider the establishment of Taiwaniaceae not reasonable, but rather support the
view that the genus is better placed between Cuninghamia and Arthrotaxis in Taxodiaceae.