3 3 The Scottish Naturalist. 



and contiguous form. The white phyllocladia are always present, 

 and contain the usual greenish-yellow gonidia. On this barren 

 state I could found nothing definitely; although I could not with- 

 hold myself from framing various affinities to other lichens. Per- 

 haps the idea that retained its hold most tenaciously was that the 

 whole was a young undeveloped state of some Stereocaulon, as St. 

 condensatum, with the brown cephalodia in excess. 



This year, in the company of members of the Perthshire Natural 

 History Society, under the leadership of Dr. Buchanan White, I 

 was fortunate enough in detecting fruit, and in a form such as I 

 could not have anticipated. Resting on the brown crust, and 

 pretty thickly scattered over it, appeared prominent tubercles of a 

 pale or pinkish-white colour, and resembling much the tubercles of 

 some Chiodecton, although larger and rougher externally, or rather 

 those of Trypethelium. Thickly scattered over these tubercles? 

 whose breadth varied from a half to one millimetre, were seen 

 minute prominent brownish-black points. A vertical section 

 through a tubercle revealed perith'ecia (entire) in connection with 

 these points, and varying in number from 8 to 50 in each tubercle. 

 The walls of these sacs or perithecia were thin and of a brownish- 

 black colour, and their contents those of a Verrucaria, viz., spores 

 8, very often uniseriate in the thecee, at first colourless, then dark- 

 brown, or ultimately nearly black, 1 septate, obovate, with one 

 loculus small, bluntly triangular, the other much larger and ovoid, 

 and their dimensions were .016 .025 x .008 .012 mm. ; para- 

 physes rather sparse, long, distinct, but soft. The hymenial gela- 

 tine was only tinted a yellowish colour by means of Iodine, while 

 the protoplasm of the thecal became, with the same reagent, a 

 fulvous colour. 



The more developed of these tubercles, which, by the way, ap- 

 peared white in section, and did not, so far as ascertained, contain 

 gonidia, had some of the white phyllocladia attached around their 

 bases, and occasionally a few higher up. 



On the whole, the constitution of these tubercles is that of some 

 Tfypethelimn^ such as Tr. Sprengelii ; but if we are to reckon the 

 brown crust and the phyllocladia as parts of one and the same 

 plant (and I do not see how we can evade this conclusion), we 

 must take a widely different view of the matter. To be sure, the 

 parasitism of a Trypethelium on the thallus of some alien lichen 

 suggests itself, but against this is the fact that the thallus in ques- 



