24 APwKIV FÖR BOTANIK. BAND 12. NIO 0. 



in Norway under the name of »scurf». In the outmost 

 cell-layer of the tuber it appears at its earliest stage as 

 formless mucous masses, and later on it looks like a coarsely 

 pored sponge. Finally the mucous masses become converted 

 into spore balls, perforated all over so that the whole interior 

 of the spore-ball is like intersected by a trellis-work or net- 

 like system of spores which like a lattice-work supports the 

 spores situated in the periphery. This fungus has later been 

 found in different localities. Its habitat must be assumed 

 to be South America as Lagerheim ^^ found it at Quito. 

 It was here in such close connection with the filaments of 

 a fungus that Lagerheim was led to the conclusion that 

 these belonged to the organism itself — an assumption in which 

 he was confirmed by oral and written communications from 

 fellow-scientists. After a closer study of Sorosphaera a. o. 

 Lagerheim, however, changed his view of the matter to this, 

 that the filaments must all the same have been without 

 genetic connection with the spore-balls and only in a delusive 

 way they had grown through the Spo7igospora tumours. The 

 spore- balls have probably (Lagerheim 1. c.) already at an 

 earlier date been observed by Wallroth, Martius and 

 Berkeley, and Rostrup^'^ likewise states, that Brunchhorst's 

 organism is identical with Tuburcinia Scabies Berk. 



It is really evident already from Brunchhorst's investi- 

 gation (1. c.) that his Spongospora Solani is no doubt an en- 

 dophytic mycetozo which is closely related to the Plasmo- 

 diophoraceae mentioned, although our knowledge of the whole 

 development of the fungus is yet very imperfect. Sub- 

 sequently Johnson 2^ is of opinion that he has seen self- 

 moving amoebae in the cells underneath a patch of scurf. 

 He likewise mentions (1. c.) that by staining with cotton- 

 blue and lactic acid 3 darker points are seen in the spores, 

 hence he is of opinion that the spores are plurinucleate. In 

 mature spores he finds the wall perforated and the contents 

 consisting of 2 — 3 self-moving bodies, presumably s warming- 

 spores. In a subsequent paper Johnson 3^'''- confirmed that 

 the movable bodies in the spore are swarming-spores. He 

 states that at the germination of the spore 8 zoospores are as 

 a rule formed. In the nuclear conditions of the spore as 

 represented by Johnson, points of resemblance are found in 

 the characteristic Ceraiiomyxa, whose cytology has been studied 



