Explanation of Plate XXI. 



Helotium citrixum (Hedw.) Fr. 



Fig. i, a. Group of plants to show habitat, natural size. 



Fig. i, b. Plants enlarged, x 3. 



Fig. i, c. Ascus and paraphyses, x 1500. 



Fig. i, d. Spores, x 2000. 



Geopyxis nebulosa ( Ckc. ) Sacc. 



Fig. ii, a. Group of plants showing habitat, natural size. 



Fig. ii, b. One plant, x 3. 



Fig. ii, c. Ascus and paraphyses, x 500. 



Fig. ii, e. .Spores, x 800. 



