CHAPTER V. COMPARATIVE REVIEW. GASTROMFCETES. 



39 



which anastomose with one another in every direction and pass on one side into the 

 tissue of the peripheral peridium, on the other it may be into that of the central 

 column, seeming as if they radiated from it. The chambers of Polysaccum are larger, 

 of the size even of a pea, and are less irregular. 



The chambers are in most cases in countless numbers; they form altogether 

 a mass of tissue which is distinguished from the adjoining tissue by its chambered 

 structure and by the formation of spores and is known as the gkba, 



As regards the more minute structure, we may distinguish a middle layer or 

 trama in the walls of each chamber, and a hymenial layer, on both surfaces of the 

 trama. The two parts (Fig. 142) resemble in all essential points the parts of the 

 same name in the Hymenomycetes. In the cases which have been most thoroughly 

 examined (the Hymenogastreae, Phalloideae, Lycoperdon, Bovista, Scleroderma, Geas- 

 ter) the trama is formed of a weft of copiously branched hyphae, which chiefly run 

 parallel to the surface of the walls, and pass without interruption from one chamber- 

 wall to the adjoining ones and into the tissue 

 of the peridium. Numerous closely packed 

 branches from the hyphae of the trama run 

 towards the interior of the chambers, and there 

 form the hymenial tissue. In some cases they 

 are comparatively short, of uniform height and 

 placed palisade-like side by side and perpen- 

 dicularly upon the surface of the trama ; thus 

 they form a sharply defined hymenial layer 

 which lines the empty cavity of the chamber 

 and is exactly like that of the Hymenomy- 

 cetes (very many Hymenogastreae (Fig. 142), 

 species of Geaster, Lycoperdon, Phallus). In 

 another series of cases (Melanogaster, Sclero- 

 derma, Polysaccum, Geaster hygrometricus), 

 all the hyphae which enter a chamber from the 

 hymenium are elongated, copiously branched, 

 and woven together into a weft which fills 

 the chamber. 



The special formations also of basidia and paraphyses in most Hymenogastreae 

 scarcely differ at all from those of any Hymenomycetes except the Tremellineae. The 

 basidia of some Lycoperdaceae and Phalloideae, described already on page 63, vary 

 a little more from them, but only in points of special conformation. Those of Geaster 

 tunicatus and Tulostoma are strangely shaped objects; the former are ellipsoid to 

 flask-shaped vesicles with a narrowly conical neck, the apex of which puts out about 

 six sterigmata which abjoint spores; the latter (Fig. 143) are narrowly club-shaped 

 cells which abjoint four almost unstalked round spores on their lateral faces. 



T. There is not much to add to what has been already said of the Hymeno- 

 gastreae. The gleba retains the structure which has been described from the 

 commencement of its formation to its perfect maturity (Fig. 141). Its tissue is 

 all the while either fleshy and formed of thin-walled juicy cells, the interstices 

 conveying air or fluid, as in Hymenogaster Klotzschii, Tul. and Octaviania carnea, 



FIG. 142. Octavianiaa.rttrosferma.Vitt. Thin section 

 of the wall of a chamber of the gleba : t trama, h hymenium 

 with five basidia forming spores. From Tulasne, Fungi 

 hypogael Magn. 180 times. 



