4 LINDSAY, ON POLYMORPHISM IN LICHENS. 



by him Spermogonia and Pycnidia. The distinction which I 

 recognise — and hereto append — is simply an anatomical one 

 — one of convenience. Hereafter it may prove to be coincident 

 w^ith a physiological difference ; but as yet the function of 

 neither Spermogonium nor Pycnidium has been satisfactorily 

 demonstrated or determined. 



Anatomical or Structural Distinction between Spermogonia 

 and Pycnidia. 



Externally indistinguishable, being similar as to site, size, 

 form, and colour ; verrucseform, papillseform, or punctiform 

 conceptacles, generally black, sometimes vi^hite-pruinose ; in- 

 terior — of same or of a different colour, or subhyaline. 



I. Spermatia. 



1. Form. — Generally linear 

 and cylindrical ; long in pro- 

 portion to their breadth ; some- 

 times in exceptional cases split 

 into two after being shed from 

 their sterigmata ; of regular 

 form ; simple ; straight or 

 curved. 



2. Size. — Generally mi- 

 nute, especially as regards 

 their transverse dimension, 

 compared with stylospores ; 

 sometimes divide into two ; 

 otherwise uniform ; frequent- 

 ly atomic (and then mostly 

 regularly ellipsoid or sub- 

 spherical). 



3. Number. — Usually in 

 myriads. 



4. Colour. — Always hya- 

 line — devoid of colour. 



5. Texture. — Solid and ho- 

 mogeneous. 



6. Site, — Borne on apices 



I. Stylospores. 



1. Form. — Generally some 

 modification of spherical [ob- 

 long-ellipsoid, pyriform,oval] ; 

 frequently broad in propor- 

 tion to length; variable and 

 irregular ; sometimes bears a 

 relation to that of the spori- 

 dium ; sometimes multicellu- 

 lar and septate. 



2. Size. — Usually larger 

 in all dimensions ; variable. 



3. Number. — Usually less 

 numerous than the sperma- 

 tia. 



4. Colour. — Sometimespale 

 yellow, though usually co- 

 lourless. 



5. Texture. — Vesicular or 

 cellular ; heterogeneous ; con- 

 tents frequently oily, or gra- 

 nular, or both. 



6. Site. — Borne on the 



