16 Dansk Botanisk Arkiv, Bd. 3. Nr. 1. 



1. Erect filaments about 5—6,« thick. 



a. Sporangia sessile or pedicellate, fusiform .... 



4. A. netrocarpiim. 

 ß. Sporangia sessile or pedicellate or several to- 

 gether upon short branchlets, oblong-hnear . . 



5. A. gracile. 

 y. Branchlets mostly opposite with mostly several 



sporangia 6. A. globosum. 



2. Erect filaments about 8 — 10 j« thick. 



a. Cells proportionally short, mostly barrel-shaped, 



hairs present 7. A. Sancti Thoniæ. 



ß. Cells cylindric, hairs wanting. 



aa. Sporangia seriate, mostly sessile, sometimes 



. . pedicellate 8. .4. seriatum. 



bb. Sporangia mostly placed 1 — 2 upon bran- 

 chlets 9. A. flexuosum. 



B. The base of the plant partly endophytic. 



a. Germinating spore persistent at the base of the plant. 



a. Spore with a single endophytic, obovate or 



subclavate, descending process .... 10. A. iinipes. 



ß. Spore with a cuneate process and, sometimes, with 



short epiphytic horizontal branches 11. A. opetigenum. 



b. Epiphytic basal disc with endophytic process 12. A. robustiim. 



c. Epiphytic and endophytic filaments ... 13. ^. bisporiim. 



C. The whole base of the plant endophytic. 



a. The germinating spore persistent and easily recogniz- 

 able. 



1. The spore remains undivided 14. ,4, occidentale. 



2. The germinating spore is divided into two cells . . 



15. A. comptum. 

 b The original spore not recognizable. 



1. Base composed of more or less horizontal creeping 

 filaments. 

 a. The base immersed in the loose tissue of the 



host plant 16. A. Avrainvilleæ. 



ß. The base immersed in the thick wall of the 

 host plant; endophytic filaments moniliform . . 



17. A. hormorhiziim. 

 y. The endophytic filaments immersed in the wall 



and between the cells of the host . . 18. A. Hypneæ. 

 d. The endophytic filaments widely spread in the 



tissue of the host . : . 19. ^. repens. 



