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

entire.Petiole about 4.5 mm long.Midvein distinct,
about 0.4^0.5 mm in thickness; alternating
secondary veins departing midvein at medium to
wide angles, appear to branch 1/2 to 2/3 distance
towards the leaf margin and joining with intramarginal
vein.Tertiary and smaller veins thin,
form a dense network of polygonal areoles.
Holotype: SC10026, Plate V, 1B, 2; Fig.4G.
Etymology: Xingxuephyllum, named in honor of
Professor Xingxue Li of the Nanjing Institute of
Geology and Palaeontology, Academia Sinica for
his contributions to the study of the early angiosperms
from NE China during the 1950s to
1990s; jixiensis, the locality of the new species.
Discussion: The leaf is probably connected organically
with the in£orescence of Xingxueina heilongjiangensis
gen.et sp.nov.(see below).Since the
joint part of the present leaf to the in£orescence is
not well-preserved, the authors will give a new
taxon name to the present leaf.However, names
of the leaf and in£orescence will be combined to
the same taxon when better material showing
clear organic connection mentioned above has
been found.Morphologically, the present leaf is
more or less similar to Shenkuoa, but the latter
has triangular and slightly acute apex which is not
shown in the present species.Moreover, Shenkuoa
is incompletely preserved in its leaf base, which is
di⁄cult to compare to the present species.
Material: 2 specimens.
Locality and horizon: Ibid., in the W-B section
bed No.47.
Genus Xingxueina Sun et Dilcher, 1997
Type: Xingxueina heilongjiangensis Sun et Dilcher
Xingxueina heilongjiangensis Sun et Dilcher
Plate V, 1A, 3^5; Plate VI, 1^6; Fig.4G
Synonyms:
Plate IV.
G. Sun, D.L. Dilcher / Review of Palaeobotany and Palynology 121 (2002) 91^112 105
1995 Xingxueina heilongjiangensis Sun et Dilcher; Sun, p.
429, text-¢g.9^2, 8 [nomen invalidum].
1996 Xingxueina heilongjiangensis Sun et Dilcher; Sun and
Dilcher, p.393, pl.2, ¢gs.1^6; text-¢g.1E [nomen
invalidum].
1997 Xingxueina heilongjiangensis Sun et Dilcher; Sun and
Dilcher, p.137, pl.1, ¢gs.1^7; pl.2, ¢gs.1^6; text-
¢g.2.
Description: In£orescence elongate, about 4.2^4.6
mm wide and more than 14 mm long (incomplete
length preserved), consisting of numerous small
£orets borne helically upon an axis.The peduncle
or stock below the position of the £orets is
smooth, slightly bent or arching, 1.2^1.5 mm
wide by 20 mm long borne in the axil of a leaf.
Florets subtended by bracts, 0.8U1.2 mm, £orets
rounded, small, 1.1^1.5 mm in diameter and
crowded helically upon axis.Structure of individual
£oret not understood but pollen in situ have
been found.Pollen nearly circular, 15^20 Wm
in diameter, seemingly inaperturate, exine reticulate
and tectate-columellate, muri more or less
smooth, 0.3 Wm wide, net-like, areoles irregularly
polygonal, about 0.2^1.0 Wm in diameter.
Discussion: The present in£orescence is characterized
by its small size, stout and longer peduncle,
and in situ inaperturate pollen which di¡ers from
those known so far in the world.The present
pollen bears some resemblance to Afropollis
from Israel (Brenner, 1996) but di¡ers in having
smaller areoles and smoother muri on the exine.
Brenner (1996) reported on the oldest known angiosperm
pollen from a core sample taken from
two wells with sediments of late Valanginian to
late Hauterivian age, in Israel (Brenner and Bicko¡,
1992).He reports that the earliest known
angiosperm pollen consist of small, circular, inaperturate
forms with tectate-columellate exine
(Brenner, 1996), however, the pollen is known
1^7. Zhengia chinensis Sun et Dilcher gen.et sp.nov.
1, 2. Showing two incomplete leaves, Holotype SC10023, 10024.1.Bar = 0.5 cm.2.Bar = 0.33 cm.
3^6.Lower cuticle (inside view), SC10023.
3, 6.Stomatal zones, SEM0964, 0965.3.Bar = 30 Wm.6.Bar = 30 Wm.
4, 5.Stomata in detail, SEM0966, 0967.4.Bar = 10 Wm.5.Bar = 10 Wm.
7.Pits and uneven periclinal walls in lower cuticle (outside view), PB16776, SEM0673.Bar = 25 Wm.