LINDSAY, ON POLYMORPHISM IN LICHENS. 9 



gonia in the proportion of twenty of the former to thirty of 

 the latter.* 



In a few cases, of which I subjoin illustrations, I have met 

 with a certain resemblance in form between the Stylospores 

 and Sporidia. There is insufficient ground, as yet, for 

 supposing that this is other than an accidental coincidence. 

 But should there hereafter prove to be a morphological rela- 

 tion between the two, holding good through genera and 

 groups, it would afford a certain additional probability in 

 favour of the supposed function of the Stylos j)ores — of the 

 present current belief that they are secondary spores, capable 

 of germination. 



Illustrative examples — 



Opegrapha pulicaris ', Spores fvLSiioxvn.; 3-5-septate. 



„ „ Stylospores ellipsoid or oblong ; fre- 



quently 3-septate. 

 O. atra ; Spores fusiform, or obovate-fusiform ; 3-septate. 

 „ Stylospores broadly ellipsoid, or oblong ; 1- sep- 

 tate. 

 Verrucaria Taylori ; >§j»ore5 subfusiform ; 1 -septate. 



„ „ Stylospores broadly ellipsoid or oblong ; 



1 -septate. 

 V. cinereo-pruinosa ; Spores oblong ; constricted in middle ; 



1-septate. 

 „ Stylospores oblong or ellipsoid ; sometimes figure- 



8 or dumb-bell-shaped. 

 V. chlorotica ; Spores oblong ; simple. 



„ Stylospores oblong, or oblong-oval, or pyri- 



form, or dumb-bell-shaped ; sometimes 

 1-septate. 

 Lecidea abietina ; Spores acicular or subfusiform ; 3-sep- 

 tate. 

 „ Stylospores ; ellipsoid or fusiform ; simple. 



Nylander and other lichenologists apparently regard Sper- 

 mogonia as male or complementary organs of reproduction. 

 There are many arguments in favour of such a view ; but the 

 function has yet to be proved. There is no reason to doubt 



* Gibelli found Pycnidia in Verrucaria carp'mea^ Pers., Sagedia carpinea, 

 Mass., S. Zizi/pki, M?LSS., S. callopisma, Mass., S. Thuretii, KcJrb., Pyremda 

 mitmta, Nseg., P. olivacea, Pers., Verrucaria gibeUiana, Gar. While Fuisting, 

 of Berlin, met with them in Opegropha varia, Pers., Acrocordia gemminaia, 

 Mass., A. term, Kovh., Sagedia neirospora, Hepp., /S*. aenea, Wallr. \\\ Acro- 

 cordia term tlie stylospores are simple ; in Opegrapha varia, Acrocordia gem- 

 minata, and the maiority of lichens, in which they occur, septate. 



