20 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 8l 



fere parallelis, attenuatis, ad medium evanidis. rete opaco, chloro- 

 phylloso, cellulis laevibus, hexagonis, parietibus tenuibus ; folia ramea 

 similia sed minora. Caetera desunt. 



A curious plant, which is very different from all the species of the 

 genus to which I could compare it, by the leaves dentate in the upper 

 two-thirds, by its smooth obscure areolation formed by thin-walled 

 cells, and by the insensibly attenuate costae not extending beyond the 

 middle of the leaf. It has the habit of P. fasciailatunv C. M., but the 

 leaves of the latter are of a different form ; moreover, the costa, which 

 plainly contrasts with the areolation, stops abruptly, without attenua- 

 tion, and projects beyond the lamina. 



HOOKERIACEAE 

 CYCLODICTYON ALBICANS (Sw.) Broth. 

 Hypiuim albicans Sw. Prodr. Veg. Ind. Occ. 140. 1788. 

 Morelia : Campanario ( 772 1 ) . 



CYCLODICTYON ARSENEI Ther., sp. nov. 



(Fk;. 7) 



Distrito Federal: Cuajimalpa, alt. 3,100 m. (9489). 



C. albicanti (Sw.) Broth, et C. luimcctato Card, proximum, sed 

 differt rete densiore, cellulis magis chlorophyllosis, praesertim limbo 

 latissimo e 3-4 seriebus cellularum formato. 



Fig. 7. — Cyclodictyon Arscnci Tlier. i, 2, 3, dorsal and lateral leaves; 4, upper 

 and marginal cells near point a : 5, median and marginal cells near point c. 



