148 Transactions British Mycological Society. 



from which the germ-tube is about to arise first becomes pale 

 coloured (Plate IV, fig. 10, a) and the terminal cell begins to 

 enlarge and soon projects sHghtly. At this stage the contents 

 of this cell and the wall are almost similar in colour and in 

 consequence the outline of the ca\aty can only be seen with 

 difficulty. Soon a small papilla-like outgrowth appears piercing 

 the outer dark-coloured portion of the wall (Plate IV, fig. 8, A 

 and b). This outgrowth which arises from the inner portion of 

 the spore wall is also pale in colour; apparently its passage 

 through the outermost dark layer is the result partly of the 

 wall becoming mucilaginous and partly of the rupture of the 

 portion of the outer layer lying immediately over it. In the 

 early stages it is merely a thickening of the wall but as it increases 

 in size a definite cavity appears which is connected by a narrow 

 channel with the cavity of the cell from the centre of whose 

 wall the tube has originally arisen (Plate IV, fig. 8, c). At this 

 stage the germ-tube is generally as wide as the breadth of the 

 end of the spore from which it has arisen, but in one or two 

 cases it appeared to be constricted as if the original perforation 

 of the outer layer had been insufficiently large to allow the 

 tube to attain its full size (Plate IV, fig. 8, c). The outermost 

 layer of the wall is always visible as a sort of collar round the 

 base of the germ-tube, its limit being sharply defined and having 

 somewhat the appearance of a cross-septum. Later the germ- 

 tube is thin-walled and hyahne with a number of oil-globules 

 irregularly distributed throughout the contents; the basal 

 portion is usually swoUen and possesses a few transverse septa 

 (Plate IV, fig. 10, B and c). 



The mycelium formed by the germinating spores remains 

 hyaline for a considerable period, being a translucent, very pale 

 sea-green; it branches but rarely. After about a week's growth, 

 it gradually assumes a brown colour and a floccose wooUy appear- 

 ance, and the hyphae attain a breadth of about 4/x. It is then 

 very similar to the mycehum found in infected host tissues 

 where it is very conspicuous by reason of its colour and size. 

 The growing points of the mycelium are always slightly swollen, 

 their apices always being rounded and smooth. After about a 

 fortnight's growtli in the liquid culture the mycehum was found 

 on examination to bear spores at the ends of the ordinary hyphae 

 quite apart from any fructification. Such spores (Plate IV, 

 fig. 12, A and c) are similar in most respects to those found in 

 the fructifications, though some are rather bent and curved 

 in form (Plate IV, fig. 12, b). Fig. 11 shows early stages in 

 the formation of these spores. 



Very similar results are obtained in the case of the cultures 

 grown on the extract in agar ; the mycelium formed is identical 

 with that already described and bears spores at the ends of 



