48 LINDSAY, ON A^ V'- OTH ALLLS. 



spermus parasitic on it is rare in Germany. I have had 

 no opportunity of examining it. When its minute 

 anatomy is fully investigated^ good grounds may appear for 

 retaining it as an indej)endent species ; meanwhile I cannot 

 give it a higher place than that of a variety. Tulasne 

 himself confesses, "Abrothallum Smithii et hunc prsesertim 

 qui in Parmelia tiliacea parasitatur summopere aemulatur." 



In A. SmWiii " Guttula oleosa in utroque cujusvis 

 sporae maturae locello includitur/^ says Tulasne. In 

 certain cases I have noticed secondary cellules or nuclei 

 in the spores : in others I have not. They were dis- 

 tinct in specimens fi'om Craig-y-Barns, Dunk eld : they 

 were absent in A. WeluntzscJiu, from Torquay^ and in A. 

 Smithii, from the Wrekin, Sliropshire (both contained in 

 Leighton's ' Lich. Brit, exsicc.^) Frequently one compara- 

 tively large cellule occurred in each loculus, lying usually 

 towards the outer extremity thereof: sometimes there were 

 two in each^ their size being smaller ; or one of the loculi 

 contained a large nucleus, while the other contained two 

 smaller ones. In apothecia from certain localities, or on 

 particular thalli, this character of the spores was pretty 

 constant ; but the nuclei in question were as frequently, in 

 other specimens, absent. I could not satisfy myself as to 

 the oily nature of these bodies ; they appeared to me to be 

 too regular in their form, too iniiform in their position, too 

 constant in certain specimens, while they were altogether 

 absent in others, to be mere " guttula oleosa." The use of 

 ether, aqua potassse, aqua ammonise, and other reagents, 

 has satisfied me of the oily nature of the globules and 

 protoplasm of the stylospores, and also of a portion, at least, 

 of the protoplasm of the spores of ^. oxysporns. But I have 

 been unable to convince myself that the nuclei of the latter, 

 or of the spores of A. Smithii, are solely or partially oily. 

 Another difficulty frequently occurs in regard to determining 

 the nature of the nuclei of certain spores. The characteristic 

 yellow nuclei of the spores oi Pcn'melia pariethni,ioY example, 

 have been variously regarded as an external coating of the 

 ends of the spore, as secondary celhiles occupying the opposite 

 extremities of the interior of a cell, having thin walls, or as 

 vacuoles hollo^ved in the material of a thick-walled or solid 

 spore, and full of an oily or other protoplasm. It seems 

 probable that spores and nuclei, possessing these varied 

 characters, really do exist, though, in particular instances, it 

 is difficult to decide to which of the classes above mentioned 

 to refer them. In the spores of the Abrothalli the nuclei — 

 be they cellules or globidcs — appear to occupy the interior 



