SPERMOGONIA 205 



He also regards as macrospores those of the pycnidia of Calicium tra- 

 chelinum which Moller was able to germinate so successfully, and all the 

 more so as they were brownish in colour, true microspores or spermatia 

 being colourless. 



Miiller' has recorded some observations on the pycnidia and stylospores 

 of the Strigulaceae, a family of tropical lichens inhabiting the leaves of 

 the higher plants. On the thallus of Strigula elegans var. tre77iula from 

 Madagascar and from India, he found pycnidia with stylospores of abnormal 

 dimensions measuring 18-26 fi in length and 3/i in width, and with i to 7 

 cross septa. In Strigula complanata var. genuina the stylospores were 2-8- 

 septate and varied from 7-65 /i in length, some of the spores being thus 

 ten times longer than others, while the width remained the same. Miiller 

 considers that in these cases the stylospore has already grown to, a septate 

 hypha while in the pycnidium. As in the pycnidiospores, described later 

 by Hedlund, the spores had germinated by increase in length follo\\ed by 

 septation. 



The spermogonia of Strigula, which are exactly similar to the pycnidia 

 in size and structure, produce spermatia, measuring about 3/n x 2/i, and it is 

 suggested by Miiller that the stylospores may represent merely an advanced 

 stage of development of these spermatia. Both organs were constantly 

 associated on the same thallus ; but whereas the spermogonia were abundant 

 on the younger part of the thallus at the periphery, they were almost 

 entirely replaced by pycnidia on the older portions near the centre, only 

 a very few spermogonia (presumablj' younger pycnidial stages) being found 

 in that region. 



Lindsay'' has described a great many different lichen pycnidia, but in 

 many instances he must have been dealing with species of the "Fungi imper- 

 fecti" that were growing in association with the scattered granules of 

 crustaceous lichens. There are many fungi — Discomycetes and Pyreno- 

 mycetes — parasitic on lichen thalli, and he has, in some cases, undoubtedly 

 been describing their secondary pycnidial form of fruit, which indeed may 

 appear far more frequently than the more perfect ascigerous form, and might 

 easily be mistaken for the pycnidial fructification of the lichen. 



G. General Survey 



a. Sexual or Asexual. It has been necessary to give the preceding 

 detailed account of these various structures — pycnidia or spermogonia — in 

 view of the extreme importance attached to them as the possible male 

 organs of the lichen plant, and, in giving the results obtained by different 

 workers, the terminology employed by each one has been adopted as far as 



'^ Miiller 1885. ^ Lindsay 1859 ^"'i 1872. 



