SPERMOGONIA 193 



B. SPERMOGONIA AS MALE ORGANS 



Interest in these minute " tubercles " and their enclosed " corpuscles " 

 was revived by Itzigsohn' who examined them with an improved microscope. 

 He macerated in water during a few days that part of the thallus on which 

 they were developed, and, at the end of the time, discovered that the 

 solution contained large numbers of motile bodies which he naturally took 

 to be the corpuscles from the broken down tubercles. He claimed to have 

 established their function as male motile cells or spermatozoa. The discovery 

 seemed not only to prove their sexual nature, but to link up the reproduction 

 of lichens with that of the higher cryptogams. The tubercles in which the 

 " spermatozoa '' were produced he designated as antheridia. More prolonged 

 maceration of the tissue to the very verge of decay yielded still larger numbers 

 of the "spermatozoa" which we now recognize to have been motile bacilli. 



Tulasne^ next took up the subject, and failing to find the motile cells, 

 he wrongly insisted that Itzigsohn had been misled by mere Brownian 

 movement, but at the same time he accepted the theory that the minute 

 conceptacles were spermogonia or male organs of lichens. He also pointed 

 out that their constant occurrence on the thallus of practically every species 

 of lichen, and their definite form, though with considerable variation, rendered 

 it impossible to regard them as accidental or of no importance to the life of 

 the plant. He compared them with fungal pycnidia such as Phyllosticta or 

 Septoria which outwardly they resembled, but whereas the pycnidial spores 

 germinated freely, the spermatia of the spermogonia, as far as his experience 

 went, were incapable of germination. 



C. Occurrence and Distribution 



a. Relation to Thallus and Apothecxa. We owe to Tulasne^ the 

 first comparative study of lichen spermogonia. He described not only 

 their outward form, but their minute structure, in a considerable number 

 of representative species. A few years later Lindsay* published a memoir 

 dealing with the spermogonia of the larger foliose and fruticose lichens, and, 

 in a second paper, he embodied the results of his study of an equally ex- 

 tensive selection of crustaceous species. Lindsay's work is unfortunately 

 somewhat damaged by faulty determination of the lichens he examined, and 

 by lack of the necessary discrimination between one thallus and another of 

 associated and intermingled species. Both memoirs contain, however, much 

 valuable information as to the forms of spermogonia, with their spermatio- 

 phores and spermatia, and as to their distribution over the lichen thallus. 



Though spermogonia are mostly found associated with apothecia, yet 



' Itzigsohn 1850. 2 Tulasne 1851. ^ Tulasne 1852. ■* Lindsay 1859 and 1872. 



S. L. 13 



