tricha caespitosa_ Sturg., p. 172.

Fig. 12. A cluster of sporangia, x 4.

Fig. 13. The capillitium highly magnified.

Fig. 14. A single spore, x 1600.

[Illustration: PLATE XI]

EXPLANATION OF PLATE XII

_Lindbladia effusa_ (Ehr.) Rost., p. 204.

Fig. 1. Fructification, natural size.

Fig. 2. Portion of same in section, x 3.

_Reticularia lycoperdon_ Bull., p. 210.

Fig. 3. Residual capillitial structure, the spores blown away; about
natural size.

_Enteridium splendens_ Morg., p. 211.

Fig. 4. Fructification, a large one, natural size.

Fig. 5. Same in section, x 3.

_Arcyria ferruginea_ Sauter, p. 253.

Fig. 6. Three sporangia, magnified about 10 times.

Fig. 6 _a_. A single spore, magnified.

Fig. 6 _b_. Capillitial thread.

_Licea variabilis_ Schrad., p. 200.

Fig. 7. Sporangia, magnified about 6 times.

Fig. 8. Spore, magnified to show surface characters.

_Tubifera casparyi_ (Rost.) Macbr., p. 207.

Fig. 9. A group of sporangia; shows the pseudo-columellae; x about 5.

_Licea biforis_ Morg., p. 201.

Fig. 10. Sporangia dehiscent, magnified about 10 times.

_Orcadella operculata_ Wing., p. 203.

Fig. 11. Sporangia, magnified about 30 times.

_Cribraria argillacea_ Pers., p. 218.

Fig. 12. Sporangia, magnified about 10 times.

Fig. 13. A single sporangium, x about 40.

See also Plate XVII., Fig. 1.

_Tubifera ferruginosa_ (Batsch) Macbr., p. 206.

Fig. 14. Sporangia magnified to show apiculate tops. Cf.

_Comatricha ellisii_ Morg., p. 184.

Fig. 15. Sporangium, x 40.

Fig. 15 _a_. A single spore, x 1000.

_Comatricha pulchella_ (Bab.) Rost, p. 183; vid. p. 284.

Fig. 16. Sporangium, x 20.

Fig. 16 _a_. A single spore, x 1000.

_Comatricha subcaespitosa_ Peck, p. 185.

Fig. 17. Sporangium, x 20.

Fig. 17 _a_. A single spore, x 1000.

_Comatricha gracilis_ Wingate, p. 183.

Fig. 18. Sporangium, x 20.

Fig. 18 _a_. A single spore, x 1000.

[Illustration: PLATE XII]

EXPLANATION OF PLATE XIII

_Heterotrichia gabriellae_ Mass., p. 257.

Fig. 1. A group of sporangia, one expanded, the others empty, x 15.

Fig. 1 _a_. Capillitium of the species, x 600.

_Calonema aureum_ Morg., p. 266.

Fig. 2. A cluster of sporangia, magnified about 15 times.

Fig. 2 _a_. The tip of an elater of the same species, x 1000.

Fig. 2 _b_. A single spore, x 1000.

Fig. 2 _c_. A bit of the sporangium wall, x 600.

_Stemonitis pallida_