The megasporangiate cone has an axis which agrees in its structure with that of the vegetative stem and bears several megasporophylls approximately at right-angles. As in the foliage leaves, the ligule is prominent and large, and lies in a groove which contains also the megasporangium; both ligule, _l_, and sporangium, _s_, as seen in the transverse section represented in fig. 219, D, are covered by an integument or velum which arises in the proximal part of the leaf and leaves a circular micropylar opening at the beak-like apex of the sporangium. The circular micropyle is surrounded by numerous hairs borne on the integument and which presumably played the part of a feathery stigma. A single megaspore with a thin membrane, _m_, abuts on the fairly strong sporangial wall, _s_; in some cases the sporangium and megaspore walls may be indistinguishable, a feature suggesting comparison with seed-structure. Some megaspores have been found filled with a prothallus. The longitudinal section shown in fig. 219, A, illustrates the characteristic horizontal position of the megasporophyll, as also the relation of the ligule, _l_, to the sporophyll with its single vascular bundle, and to the hairy integument, which overarches both sporangium and ligule; the line _m_ shows the position of the megaspore-membrane, detached from the sporangial wall on the upper side but in contact with it below. The microsporophyll shown in 219, E, was originally referred to _Miadesmia_ but has since been recognised by Watson[673] as that of a _Bothrostrobus_. _Miadesmia_ affords an example of a Palaeozoic plant comparable with _Isoetes_ and _Selaginella_; it agrees also with _Lepidocarpon_ in possessing true seeds, and with Watson’s _Bothrodendron_ cone in the shape of the sporangia, which are more like those of _Selaginella_ than the radially elongated sporangia of _Lepidostrobus_. _Miadesmia_ agrees with _Selaginella_, e.g. _S. spinosa_, in its stelar structure, in the form of the sporangia, and in the presence of a ligule. It is distinguished by having only one instead of four megaspores in a sporangium, in the possession of an integument which formed a close investment to the spore and served as a stigma (comparable with the stigma-like integument of the male flower of _Welwitschia_), and in the shedding of the megasporophylls, which have been aptly compared with winged seeds. [Sidenote: LEPIDOCARPON]