EARLY CRETACEOUS FLORA OF MONGOLIA

lsely leaved branches. Second branching is at interval of 1—3 mm, so that the branches seem whorled.
sequent forking is unequal, giving the shoot a pseudomonopodial aspect, with the main axis straightened
1 the lateral branches distichous. The lateral branches are at acute angle to the main axis, some of them bent
:kwards, at interval of 10 mm in the middle portion of a shoot, but more crowded at the apex. Leaves on the
in axis and at the angle of branching are broadly ovate or rhomboidal, about 3—4 x 2—2.5 mm, imbricate,
:h the obliquely decurrent, clasping base and the attenuate, hair-like apex, funnel-shaped or folded along the
n, flabellately striated, showing the ligular scar as a minute pit at the base (PL 2, fig. 24). Leaves on the lateral
nches are dimorphous, four-ranked (PL 2, figs. 17, 18): those in the ventral ranks like on the main axis, the
:sal ones small, about 1 mm long, not always discernible. Adventitious roots, when preserved, attached in the
Is of the ventral leaves. Rounded bodies, 2—7 mm in diameter, with a thick folded cuticle associated with the
>ots, might be tubers.
;t-Fig. 2. Limnothetis gobiensis sp. nov., reconstruction of a fertile zone.
In the fertile portion of a shoot, the specialized fertile brachyblasts (sporangiophores) are in the axil of each
ltral leaf, crowded, overlapping, arranged distichously, alternate. The sporangiophores are elliptical, about
nm long, consisting of a short axis bearing a single terminal sporangium and about 10 appressed bracts which
se above the sporangium (PL 2, figs. 20, 21).
Sporangia are mostly elliptical, 1 x 0.6 mm, containing numerous small spores (10 sporangia were macerated
spores). Occasional sporangia are considerably larger, 1.2 x 1 mm, rounded and appear more bulky (PL 2,
. 22). They are limonized, not yielding to maceration.
Spores are about several hundred per sporangium, trilete, amb rounded, diameter 44—60 mm, leasurae
sed, arching, extending to the amb. Exine thin, trilete, folded. Many spores are folded along two leasurae so
.t they seem elliptical, with pointed ends (PL 3, fig. 31).
Dispersed organs associated with Limnothetis gobiensis sp. nov.
Megaspores found on the rock surface in close association with the shoots (PL 3, figs. 25, 26, 29) are all of one
id, spherical, diameter 600-800 jLtm, amb rounded, fringe (arcuate lamellae) about 50 /лт wide, trilete ridges
ending to equator. Exine is reticulate, with polygonal meshes 7—8 /лт wide, thickened at the corners, elongate
i passing into concentrical ridges in the fringe. The exine is also ornamented with spines, more numerous on the
tal face than on the proximal. The spine stumps are rounded, set on the corners of the reticulum, occasionally
ising concentrical arrangement of the meshes.
There are also numerous reniform bodies, sometimes covering the rock surface, about 1 mm in diameter,
lvex, transversed by a median groove (PL 1, figs. 1—6). On transfer preparations these bodies show polygonal
;ontographica Abt. B. Bd. 181 2