L. Hably szerk.: Studia Botanica Hungarica 19. 1986 (Budapest, 1986)
Bande, M. B.; Awasthi, N.: New thoughts on the structure and affinities of Viracarpon hexaspermum Sahni from the Deccan Intertrappean beds of India
8-10 vertical rows, each row consisting of about 6 fruits, central axis with monocotyledonous vascular bundles. To understand the structure of the individual fruit, while preparing the longitudinal section of the fructification the section was studied and photographed at various levels of grinding.Thus a series of photographs were obtained showing the fruits cut in cross section from top to bottom (Plate II, 5, 10; Figs 3 A-E). Thus a cross-section passing through almost top of the fruit shows six free perianth-like lobes arranged in more or less circular fashion. Each lobe is wing shaped about 1 mm in width and 2 mm in thickness . In the next section passing through a somewhat lower level, the lobes are increased in dimensions and have come a little closer to each other. They also show a little curving of their lateral tips towards the centre. This process continues in the successive stages and ultimately these lobes join with each other to form the six partition walls of the hexacarpellary fruit. Thus the structures which are described as "processes" by SAHNI or ' spines' by CHITALEY are in fact distinct perianthlike lobes which are fused with the ovary wall in the lower half and form a distinct cup-like structure over it. Another important point to note is the presence of a pinheadlike protruberance on the inner surface of each lobe as seen in cross-section. This structure is present at every stage before the hexalocular condition is reached. This indicates the presence of a vertically running upraised ridge on the inner surface of each lobe. It was probably this structure which was interpreted by CHITALEY (1954) as the inner set of spines. Probably this ridge also continues to run on the top surface of each carpel as has been described in Shuklanthus superbum by VERMA (1958). The 'spines' are usually described as hairy. A study of all the cross-sections of the fruit at various levels clearly indicates that the complete cup-like structure formed by the periant-like lobes above the ovary is filled with hair coming out from the inner surface of the lobes (Plate II, 5-9; Fig. 3 A-E). LASTLY, CHITALEY (1954) has mentioned the presence of a depression in the centre of each fruit surrounded by twelve such depressions in two rings, each of six. A study of these fruits, wherever they are exposed in the vertical section, shows that contrary to depression the central axis of the fruit around which the six locules are arranged is rather raised above the level of the locules in the form of small dome like structure (Plate I, 1, 4; Fig. 4 B). The other depressions mentioned by Chitaley (1954) are not seen in any of the specimens studied. Thus, in the light of these observations the individual fruit of Viracarpon hexaspermum can be described as ebracteate, sessile, hex-angular with 6 equal locules surrounding a central core, each locule containing a single seed, the central core protruding slightly above the locules; outer wall of the ovary extending upwards in the form of six perianth-like lobes, free at the top forming a cup-like structure and joining below to give rise to the six partitions of the ovary; a vertical ridge running in the centre of each lobe on its inner surface from top to its base; the inner surface of the perianth-like lobes covered with hair (Plate II, 5-10; Fig. 4 B). With the help of these details a new reconstruction of the entire fructification as well as individual fruit has been attempted (Fig. 5). For the sake of its comparison with the earlier reconstruction of a complete furctification as suggested by NAMBÜDIRI and TIDWELL (1978), an individual fruit of Viracarpon Sahni, CHITALEY (1954) and that of Shuklanthus superbum . VERMA (1958) have also been reproduced (Figs 1 ABC D). Fig. 2 A. Longitudinal section of V. hexaspermum Sahni showing the main axis and vertical rows of fruits x 2, 2 B. Cross-section of hexaspermum Sahni showing main axis surrounded by 9 rows of fruits x 3.5
