In this article we will discuss about the sporophyte and the stamen and seed of Calymmatotheca.
The Sporophyte of Calymmatotheca:
The stem is long and slender with a presumed climbing habit, and bears spirally arranged fern-like leaves. The frond is compound with a gland, and the rachis divides equally. The pinnae are oppositely arranged.
The anatomy of the stem shows a large pith, which is parenchymatous, and stone cells in groups forming sclerotic nests are present. The mesarch primary wood surrounds the pith, and the protoxylem is surrounded by metaxylem.
The xylem of the root is mesarch, and undergoes secondary growth.
In the petiole the xylem is completely surrounded by the phloem. The anatomical structure of the leaf is not much different from that of the living ferns. The epidermis is cuticularized, and the palisade and spongy parenchymas are present. The stomata are situated on the lower surface.
The Stamen and Seed of Calymmatotheca:
The entire structure somewhat resembles the stamen of Araucaria. The fertile part is flattened into a paddle-shaped structure bearing a few pendant bilocular sporangia at its margin. In all probability the pollen grains did not give rise to pollen tubes, and the sperms would have been of the cycad type.
The Seed of Calymmatotheca:
The seed is small, terminal and barrel-shaped. It is orthotropous and symmetrical in nature with a simple set of vascular supply. It is surrounded by a glandular cupule, which can be compared to that of Juglans, Fagus, and other living members of the Cupuliferae.
The nucleus is free from the integument only at the tip, and has a conspicuous pollen chamber. Very little is known about the female gametophyte, because it is hardly preserved.
Cycadofilicales gave rise to two mesozoic phyla:
i. One with monosporangiate strobili represented in the present flora by Cycadales,
ii. The other with bisporangiate strobili represented in the Bennettitales and not represented in the present flora.
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