Early angiosperms from the Lower Cretaceous of Jixi, eastern ...

pened to fall across one another.If this would be
the case, there should be some indication that one
lays over the top of the other, which, upon close
examination in oblique light, was not the case.
Therefore, we consider that the leaf and the reproductive
axis probably belong together.The
leaf has tertiary and higher venation pattern of
a low order rank that seems to be typical of several
Lower Cretaceous angiosperm leaves.It is
most similar to a generalized Magnoliidae type
leaf. Friis and Endress (1990) suggest that the
extant members of the Magnoliidae exhibit the
most primitive characters of all £owering plant
groups.Some revisions appear to be needed
with the recent hypothesis by Brenner (1996)
and the fossil reproductive structure of Xingxueina
provides many new characters that we hope
will be useful in the overall evaluation of primitive
or early angiosperm characters.
Material: one specimen.
Locality and horizon: Ibid., in the W-B section
bed No.47.
Reproductive organ A
Plate III, 4,5
Description: In£orescence-like in character, oblong
in form, about 2 cm long by 1.1 cm wide.
Axis about 1.5^2.0 mm in thickness, more than
2.5 cm long. The structure of the reproductive
organ not understood, but some fragments look
like the individual reproductive parts preserved in
the specimen.The fragments consist of numerous
disc-like pieces (perhaps seeds or fruits), ca.0.4
mm in diameter.
Material: one specimen.
Locality and horizon: Ibid., in the W-B section
bed No.45.
Reproductive organ B
Plate III, 6,7
Plate VI.
G. Sun, D.L. Dilcher / Review of Palaeobotany and Palynology 121 (2002) 91^112 109
Description: In£orescence-like in character, incomplete
in shape, catkin-like, about 3.5 cm
long by ca. 1.2 cm wide. Axis stout, about 1.5
mm wide.Stalk visible more than 5 mm long.
The detailed structure of the reproductive organ
unknown.
Material: one specimen.
Locality and Horizon: Ibid.In the W-B section
bed No.45.
4. Discussion
The early angiosperms from the Chengzihe
Formation of Jixi, China basically are characterized
by their simple, microphyllous, entire leaves
with more or less irregular pinnate and reticulate
venation.Palynologically, the angiosperms have
apparent inaperturate pollen associated with
some dispersed monosulcate types (Shang, 1997).
Based on these characteristics, the Jixi early angiosperms
appear to be early in their development
although they already show some diversity.
The early angiosperm Dicotylophyllum pusillum
Vachr.from the Zazin Formation of the Transbaikalia,
Russia (Vachrameev, 1973, 1991; Krassilov,
1997) is quite similar to Asiatifolium elegans
from the Chengzihe Formation of Jixi, China.
The Russian angiosperm has been considered as
Hauterivian or Hauterivian^Barremian in age by
the Russian authors.In South Primorye of Russia
in the neighboring areas of Jixi, Heilongjiang,
China, there are also some early angiosperms
such as Nyssidium orientale Samylina which is
also considered as Hauterivian or Hauterivian^
Barremian (Samylina, 1968).Thus, it appears
that the Jixi angiosperms described in this paper
represent the early^middle Early Cretaceous level
of the early angiosperm development in Northeast
China and also in northeastern Asian regions.
1^6. Xingxueina heilongjiangensis Sun et Dilcher, SC10025.
1, 2, 6.Showing three pollen grains, SEM0776, 0777, 0779.1.Bar = 10 Wm.2.Bar = 1.5 Wm.6.Bar = 5 Wm.
3, 4.Showing pollen grains borne/attached to periclinal walls of the male parts of the in£orescence (inside view),
SEM0793, 0794.3.Bar = 20 Wm.4.Bar = 10 Wm.
5.Showing some pits and uneven periclinal walls (outside view), SEM0795.Bar = 6 Wm.