434 GENERA OF FERNS. 
it is distinguished by the exterior indusium of that genus 
being continuous. Presl has founded a genus (Leptopleura) 
on the Dicksonia abrupta of Willdenow, a fern which I have 
never seen, and judging from description and figure it appears 
to come near to Cystodium, but not so much as to induce me 
to view them as belonging to the same genus. 
114. SrronoBivM, Desv. J. Sm. 
(Dicksonie sp. Sw. and Auct. Patania, Presl.) 
Veins pinnate ; venules simple or forked, direct, their apices 
free and sporangiferous. Special and accessory indusia nearly 
equal, forming a reflexed, entire or bilabiate calyciform cyst, 
constituting globose exserted sori. Receptacle elevated, 
globose. 
Rhizoma creeping. Fronds bi-tripinnate, slender ; segments 
crenale multifid, smooth or pilose-glandulose ; fertile fronds 
sometimes somewhat contracted and densely soriferous, with the 
sori of the opposite margins conniving. 
Ezamp. 1. S. pilosiusculum, Desv. 2. S. strigosum, (Sw-) 
3. S. glutinosum, (Wall.) 4. S. dissectum, (Sw.) 5. S. 
adiantoides, (Humb.) 6. S. apiifolium, (Sw.) 7. S. cicu- 
tarium, (Sw.) 8. S. rubigirlosum, (Kaulf.) 9. S. obtusifolium, 
(Willd. 10, S. davallioides, (R. Br.) 
Ilust. Schk. Crypt. t. 130 B. and 131. Hook. Gen. Fil. t. 
61. A. and B. 
Obs. The creeping rhizoma and more delicate texture of 
the fronds are the chief distinction of this genus from true 
115, BaLantium, Kaulf. J. Sm. 
(Dicksonie sp., L’Hérit. Culcita, Presi.) 
Veins pinnate; venules simple or forked, direct, their apices 
free and sporangiferous. Special and accessory indusia equ 
forming a slightly reflexed oblong-transverse bilabiate cyst ; 
constituting large exserted nearly globose sori. Receptacle 
elevated, oblong. 
