Explanation of Plate 39 



I. Cexaxgium populxeum (Pers.) Rehm. 



a. Plants showing habitat natural size. 



b. One plant X 5. 



c. Aseus and paraphyses X 1000. 



d. One spore X 2000. 



II. Urxula craterium (Sehw.) Fries. 



a. Three stages in the development of plants, natural size. 



b. Aseus and paraphyses X 500. 



c. Hairs from cup X 1000. 



d. One spore X 1200. 



-i,s 



