HYPOCRELLA AND ASCHERSONIA. 186 



spores also covers the stroma, it would appear that a conti- 

 nuous production of spores takes place from each basidium. 

 When mature, the spores are extruded in coloured masses. 

 In the Lecaniicolse and the discoid species of the Aleyrodiicolse 

 the spore masses from the individual pycnidia remain distinct, 

 as a rule ; but in those species of the Aleyrodiicolae, which 

 have irregular and widely-open pj^cnidia, e.g., Ascher&onia 

 placenta, the spore masses fuse into a continuous covering 

 over the centre of the stroma. The pycnospores adhere 

 strongly to one another and fill the pycnidium with a trans- 

 lucent mass, which is not easily removed. Prolonged soaking 

 in water often fails to loosen the spores sufficiently to permit 

 their evacuation from the pycnidia in a section of the stroma, 

 and it is necessary to employ caustic potash to liberate them 

 before the hymenial layer can be examined. Webber has' 

 figured an instance in which the pycnospores were extruded 

 in erect columnar masses in the case of Aschersonia Aleyrodis, 

 and I have observed the same in Aschersonia placenta kept in 

 a glass dish in the laboratory, but, probably because of the 

 greater humidity of the atmosphere, this phenomenon does 

 not, apparently, occur in the open in Ceylon ; the nearest 

 approach to it is the columnar mass of spores, which sometimes 

 crowns Asofiersonia oxyspora. A comparison of the detached 

 spores within a pycnidium with those in the extruded spore- 

 masses leads to the conclusion that the spores increase in 

 breadth after they have become detached. 



The shape of the pycnospores shows very little variation. 

 In general they are fusoid or narrow-oval, with pointed ends. 

 When immature the broadest part is generally situated 

 towards one end, but they become more regularly oval subse- 

 quently. In a few cases they show distinctive characters, e.g., 

 in Aschersonia hasicystis {Hypocrella phyllogena), Aschersonia 

 turbinaia, a,nd Aschersonia oxystomo.. The pycnospores of ^. 

 hasicystis are usually furnished with fine points, up to 4 tx long, 

 though others, merely narrow-oval, may occur in the same 

 pycnidium. Aschersonia turhinata has broadly oval spores, 

 with abrupt short points which appear solid. The spores of .4. 

 oxystomo, appear toresemblethoseof^.^t<r6mato, but the effect 

 is produced by the concentration of the contents into an oval 



