作 者 ：Zhang Yu-Long, Wang Fu-Hsiung, Chien Nan-Feng
期 刊 ：植物分类学报 1988年 5期
Keywords:Eucommia ulmoides, Pollen morphology, Exine ultrastructure,
Abstract:
Eucommia ulmoides Oliver is endemic to China. The pollen morphology and exine
ultrastructure were examined under LM, SEM and TEM. Pollen grains are prolate, polar
axis 30.5-54.8 μm long, with the average 32.7 μm, equatorial axis 27.8-31.3 μm long, with
the average 29.2 μm, tricolporoidate, but sometimes the outline of ora could be observed and
elliptic in shape. Colpi are narrow, uequal in length, often two long and one short or two
short and one long, sometimes rather irregularly arranged, with indistinct and thin colpus
membrance. Exine psilate under LM, granulate under SEM, and shortly baculate under
TEM. Tectum is thin with dense and small granules, columellae layer consists of short ba-
cules, and foot layer very thick.
Some taxonomists (Cronquist, 1968) consider that Eucommiaceae is related to Hamameli-
dales, but others (Takhtajan, 1969) to Urticales. The Urticales is of the porate type of pollen
grains, while Eucommiaceae of tricolporoidate type, and thus the former is more advanced
than the latter. Pollen grains of some members of Hamamelidales, tricolporoidate, are simi-
lar to those of Eucommiaceae. We therefore consider that Eucommiaceae is related to Hama-
melidales.