Tectaria sect. Sagenia
Content
Distribution
Asia-Tropical, neotropic present
Throughout the distribution of the genus; c. 65 species of which c. 10 are neotropic; in Malesia 26 species.
Taxonomy
The type species of Sagenia and Microbrochis are identical in venation and both are West Indian. Presl distinguished them by the form of their indusia only, peltate in Sagenia and reniform in Microbrochis; but in fact the indusia of the type species of Sagenia are not truly peltate nor are they clearly distinct from those of the type of Microbrochis. Tectaria coadunata (J. Sm.) C. Chr. in Asia is closely related to them both and all three were regarded as conspecific by Hooker. There are allied species in Africa. Thus the Sagenia form of venation is pantropic and must have had an early origin from the free-veined form which, as above noted, is regarded as primitive for the genus Tectaria.
Presl's name Sagenia was variously misused by later authors. Baker used it (1867: 296-300) as an infrageneric name in Nephrodium, a genus defined solely by the reniform indusia of sori and comprising mainly species now placed in the family Thelypter- idaceae; thus Baker's Nephrodium § Sagenia differs from Presl's definition of Sagenia both in indusia and venation, and is most unnaturally associated with a very different group of ferns. In 1908 Van Alderwerelt revived the use of Sagenia as an infrageneric group in Aspidium, again defining it in a sense contrary to that of Presl.
Stenosemia Presl was established for one widely distributed species which has exactly Sagenia venation in sterile fronds, but much-contracted fertile fronds with a simpler venation along which the sporangia are so crowded that they appear to be acrostichoid. There is an allied species in Madagascar. Stenosemia pinnata Copeland has the frond-form of Heterogonium and is here placed in that genus.
Presl's name Sagenia was variously misused by later authors. Baker used it (1867: 296-300) as an infrageneric name in Nephrodium, a genus defined solely by the reniform indusia of sori and comprising mainly species now placed in the family Thelypter- idaceae; thus Baker's Nephrodium § Sagenia differs from Presl's definition of Sagenia both in indusia and venation, and is most unnaturally associated with a very different group of ferns. In 1908 Van Alderwerelt revived the use of Sagenia as an infrageneric group in Aspidium, again defining it in a sense contrary to that of Presl.
Stenosemia Presl was established for one widely distributed species which has exactly Sagenia venation in sterile fronds, but much-contracted fertile fronds with a simpler venation along which the sporangia are so crowded that they appear to be acrostichoid. There is an allied species in Madagascar. Stenosemia pinnata Copeland has the frond-form of Heterogonium and is here placed in that genus.