ASCOMYCETES 



37i 



generally somewhat precedes the origin of the carpogone. Under 

 the surface of the thallus a hypha not distinguishable from its neigh- 

 bours gives off a broader lateral branch, which coils itself up two or 

 three times, and then sends forth the tip of tha^coil, which, growing 

 upward, emerges through the surface of the thallus into the open. The 

 tube is commonly somewhat swollen as it passes through the superficial 

 tissue, and for some short distance above it, and attains a height above 

 the surface of four or five times its breadth. This is the trichogyne. 

 The coil as it grows is divided by transverse walls into about a dozen 

 thin-walled cells, and the trichogyne likewise into a similar number. 

 Its development having taken place, and the suitable conditions of 

 moisture having dispersed the pollinoids over the surface, these, wher- 



B 



FIG. 307. A, Leptogium microphyllum Ach., section of thallus. a, point of trichogyne ; 

 g, algal cells ; /*, hyphae, B, Collema pulposum Bernh., young carpogone. C, tncho- 

 gyne with pollinoids of L. microphyllum. D, a similar one showing union with polli- 

 noid. (A x 350, B, C, D x 750.) (After Stahl.) 



ever they come into contact with a trichogyne, stick to it, sometimes in 

 considerable numbers, and an open communication between pollinoid 

 and trichogyne is established by means of a short minute process from 

 the pollinoid. When this has been accomplished the cells of the 

 trichogyne collapse, remaining distended only where a transverse septum 

 occurs in its course, while the cells of the coil increase in volume and 

 in number through the growth of fresh transverse walls. The neigh- 

 bouring thallus-hyphae then give out numerous shoots, which not only 

 grow round the coils, but press them asunder. The hyphae on the side 

 next the surface then give off branches in that direction, the end shoots 

 of which form the first paraphyses, after displacing the intervening tissue 

 in their course. The enveloping hyphae extend laterally until a basin- 



B B 2 



