174 



BASIDIOMYCETES. 



layer of basidia or else it fills up the entire cavity. The basidia 

 as a rule bear four spores, sometimes eight (Geaster), or two 

 (Si/menogaster). The tissue of the walls (trama) consists often 

 (Lycoperdacece} of two kinds of hyphre, some thin and rich in 

 protoplasm, divided by transverse septa and bearing the basidia ; 

 others thicker and thick-walled which do not dissolve like the 

 former on the ripening of the spores, but continue to grow and 

 form a woolly, elastic mass, the capillitium, which may be regarded 

 as highly developed paraphyses. The peridium may be either 

 single or double, and presents many variations in its structure 

 and dehiscence. The mycelium is generally a number of string- 

 like strands, living in soils rich in humus. 



Order 1. Tylostomaceae. Capillitium present. After the rupture of the 

 peridium the remaining part of the fruit-body is elevated oil a long stalk. 

 Tylostoma inainmosum, on heaths. 



Order 2. Lycoperdaceae. The fruit-body has a double 

 peridium ; the external one at length breaks into fragments 

 (Lycoperdon, Bovista), or it has a compound structure of several 

 layers (Geaster) and detaches itself as a continuous envelope from 

 the inner layer, which is membranous and opens at its apex. 

 The interior of the fruit-body consists either solely of the fertile 

 gleba (Bovista, Geaster), or, in addition, of a sterile tissue at the 

 base (Lycoperdon). A capillitium is also present. 



Lycoperdon (Puff-ball) has a sterile part at the base of the fruit-body which 

 often forms a thick stalk. The surface of the peridium is generally covered 



with warts or projections. When 

 young this Fungus is edible, but 

 when ripe it is dry, and used for stop- 

 ping the flow of blood. L. giganteum, 

 which is often found growing in 

 meadows, attains a considerable size, 

 its diameter reaching as much as 

 eighteen inches. L. gemmatum (Fig. 

 180) is covered with pyramidal warts ; 

 in woods. Bovista has no sterile 

 basal part; the external peridium is 

 smooth, and falls away in irregular 

 patches. B. plumbea, on linka near 

 the sea. Geaster (Earth- star) has an 

 external peridium composed of several 

 layers, which when the fruit-body opens, split into several stellate segments. 

 These segments are very hygroscopic, and in dry weather bend backwards and so 

 raise the inner peridium into the air. The inner peridium contains the spores. 



FIG. 180.- 



' rdon gemmutum 

 (a nat. size). 



