103. Collema ] 28. COLLEMACEAE 157 



103. Collema (Hill.) Web., in Wigg., Prim. Fl. Hols. 89. 1780. 



Transforming the algal colony into a small to large, round to irregular, lobed, 

 greenish to blackish body, thallus wholly mycelial, imbedded in the host and at- 

 tached to the substratum by rhizoids; apothecia small to large, more or less 

 immersed to adnate or sessile, the disk concave to flat or slightly convex, flesh- 

 colored to brown, the algoid exciple thin to thick, entire to irregular; hypothecium 

 hyaline to brown; hymenium hyaline to brownish above; paraphyses rarely 

 branched, commonly enlarged and brownish toward the apex; asci clavate; spores 

 8, hyaline, transversely and longitudinally septate. 



The algal host is Nostoc. 



A. Spores 1-3-septate transversely 

 B. On trees and old wood 



C. Thalloid body very small, more or less crustlike 



D. Apothecia 0.15-0.25 mm. across 2. C. verruciforme 



D. Apothecia 0.4-0.8 mm. across 1. C. microphyllum 



C. Thalloid body larger, distinctly lobed 9. C. callibotrys 



B. On rocks and soil 



C. Thalloid lobes smooth above or rarely becoming granulose 



D. Apothecia 0.5-2 or 2.5 mm. across, more or less superficial 

 E. Apothecia very numerous; spores oblong-ellipsoid, 



16-30 X 8-12 fi 5. C. crispum 



E. Apothecia rarely numerous; spores ovoid-ellipsoid, 



16-24 X 8-11 u 3. C. tenax 



D. Apothecia 0.2-0.7 mm. across, appearing like pustules . 4. C. pustulatum 

 C. Thalloid lobes granulose above, or rarely somewhat smooth 

 D. On rocks; thalloid body small to middle-sized 



E. Spores 24-34X11-17/* 6. C. cheileum 



E. Spores 17-24 X 9-11 ai 8. C. furvum 



D. On soil; thalloid body minute; central lobes reduced 



and club-shaped; spores 16-30 X 7-9 /* ..... 7. C. cristatellum 

 A. Spores 3-5- or more sep ate transversely 

 B. Spores rarely more than 25 /t in length 

 C. Thalloid body smooth to wrinkled above 

 D. Apothecia more than 0.4 mm. across 



E. Thalloid margins usually plicate and crisped . . . 11. C. plicatile 



E. Thalloid margins wavy-crenate 10. C. pulposum 



D. Apothecia 0.1-0.3 mm. across 12. C. fayettensis 



C. Thalloid body granulose above 14. C. granosum 



B. Spores rarely less than 25 n in length 



C. Apothecia 1-3 mm. across; spores oblong-ellipsoid ... 13. C. glaucescens 

 C. Apo'.hecia 0.2-0.7 mm. across; spores rarely 



becoming spheroidal 4. C. pustulatum heterosporum 



1. Collema microphyllum Ach., Lich. Univ. 630. 1810. 



Transforming the algal host into an olive-green to blackish, orbicular or irregu- 

 lar lobulate body, with the minute, sometimes scattered, ascending lobes reduced, 

 subimbricated, and granulose-crenate toward the center, and those toward the 

 margin larger and flat; apothecia small, 0.4-0.8 mm. across, numerous, sessile, the 

 disk deeply concave to flat, red, the algoid exciple finally disappearing, and the 

 pale proper exciple persisting; hypothecium hyaline to brownish; spores ovoid- 

 ellipsoid, 3-septate transversely and 1-septate longitudinally, 16-25 X 8-11 /j-. 



On trees, Massachusetts, Ohio, and Illinois. 



2. Collema verruciforme (Ach.) Nyl., Syn. Meth. Lich. 1:112. pi. 4, f. 6. 1858. 



Collema furvum var. verruciforme Ach., Lich. Univ. 650,651. 1810. 



Transforming the algal colony into a minute, olivaceous or darker brown body, 

 composed of crowded, granulose, heaped or widespread, ascending, crenate lobules, 

 and becoming broken and scattered; apothecia minute, 0.15-0.25 mm. across, 

 numerous, 1-4 in each lobule, the disk deeply concave to flat, reddish brown, the 

 algoid exciple thick and dark brown; hypothecium brownish; spores spheroidal to 



