SPERMOGONIA 203 



successful, was very much slower. The pycnidiospores (or spermatia) have 

 the form of minute bent rods measuring 5*7 p x 1*5 //,. Each end of the spore 

 produced slender hyphae about the fifth or sixth day after sowing. In four 

 weeks, the whole length of the filament with the spore in the middle was 

 300 /A. In four months a patch of mycelium was formed 2 mm. in diameter. 

 Growth was even more sluggish with the pycnidiospores of Opegrapha atra. 

 In that species they are rod-shaped and 5-6 /i long. Germination took place on 

 the fifth or sixth day and in fourteen days a germination tube was produced 

 about five times the length of the spore. In four weeks the first branching 

 was noticed and was followed by a second branching in the seventh week. 

 In three months the mycelial growth measured 200-300 /* across. 



Germination was also observed in a species of Arthonia, the spores of 

 which had begun to grow while still in the pycnidium. The most complete 

 results were obtained in species of Calicium : in C. parietinum the spores, 

 which are ovoid, slightly bent, and brownish in colour, swelled to an almost 

 globose shape and then germinated by a minute point at the junction of spore 

 and sterigma, and also at the opposite end ; very rarely a third germinating 

 tube was formed. Growth was fairly rapid, so that in four weeks there was 

 a loose felt of mycelium measuring about 2 cm. x i cm. and I mm. in depth. 

 Parallel cultures were carried out with the ascospores and the results in both 

 cases were the same; in five or six weeks small black points appeared, which 

 gradually developed to pycnidia with mature pycnidiospores from which 

 further cultures were obtained. 



On C. trachelinum, which has a thin greyish-white thallus spreading over 

 old trunks of trees, the pycnidia are usually abundant. Lindsay had noted 

 two different kinds and his observation was confirmed by Moller. The 

 spores in one pycnidium are ovoid, measuring 2'5-3/iX 1*5-2/4; in the 

 other rarer form, they are rod-shaped and 5-7 /i long. In the artificial 

 cultures they both swelled, the rod-like spores to double their width before 

 germination, and sometimes several tubes were put forth. Growth was slow, 

 but of exactly the same kind from these two types of spores as from the 

 ascospores. At the end of the second month pycnidia appeared on all the 

 cultures, in each case producing the ovoid type of spore. 



In a second paper Moller 1 recorded the partially successful germination 

 of the "spermatia" of Collema (Leptogium) microphyllum, the species in which 

 Stahl had demonstrated sexual reproduction. Growth was extraordinarily 

 slow : after a month in the culture solution the first swelling of the sper- 

 matium prior to germination took place, and some time later small processes 

 were formed in two or three directions. In the fourth month a branched 

 filament was formed. 



Holler's experiments with ascospores and pycnidiospores were primarily 



1 Moller 1888. 



