| Abstract: | In the present paper pollen grains of 5 species and seed coat of 4 species of the
genus Cistanche (Orobanchaceae) from China were examined by scanning electron microscope
As a result, two types of the pollen exine sculpture are distinguished: (1) tuberculate, C. salsa
and C. lanzhouensis; (2) rugulate or fine reticulation formed by the fusion of rugae, C.
sinensis, C. deserticola and C. tubulosa. Chinese Cistanche was classified into two sections
based on the gross morphology by the present author (Zhang, 1984). C. lanzhouensis and
C. sinensis were included in one section. This classification is in conflict with the pollen type,
which indicates that the characters of pollen grains and external morphology in this genus have
evolved at different rates. The differences in pollen morphology of Chinese Cistanche can serve
as characters for delimitating species.
According to our abservation, C. lanzhouenis Z. Y. Zhang differs from the other members
of Cistanche not only in external morphology but also in pollen morphology. Pollen grains
are subprolate in this species, while prolate in the other four species, and exine sculpture is
tuberculate. The present study provides the establishment of this new species (Zhang, 1984)
with palynological evidence.
The seed coat sculpture in Chinese Cistanche are constantly alveolate, but there are some
slight differences, by which the sculpture can be divided into two types: (1) testa cells have
or have not thickenings on the inner anticlinal walls; cavernulous sculpture is present on
outer periclinal wall of some cells: C. sinensis; (2) testa cells have striate thickenings on the
inner anticlinal walls: C. salsa, C. deserticola and C. tubulosa. The characters of seed coatof some significance for the delimitation of species. |
