species of the group Hemiphlebium hâve ciliate fronds. Still 

 I think this groupiog of the species is rather artifical. 

 Among the species from the South-east African islands 

 T. BarJclyanum Bak. and T. Giesenhagenii, known to me 

 from descriptions and illustrations alone, belong to § Hemi- 

 phlebium, ail the others to § Microgonium. 



The subgenus is apparently richer in species on the islands 

 than on the African continent; the following continental 

 species hâve been described: T. erosum Willd., T. aeru- 

 gineum V. d. B. and T. palmicola V. d. B., ail from West 

 Africa; the latter differs scarcely from T. erosum, while 

 T. aerugineum certainly is a good species, differing from 

 T. erosum by the lack of an intramarginal vein and closely 

 related to T. fidgens, described below; it was by KuHN 

 and by myself (Index) referred to T. erosum; also T. Mei- 

 tenii G. Chr. {T. subsessile Mett.), from West Africa, is 

 perhaps a species of the subgenus, although it totally 

 lacks spurious veins. T. Rohinsonii Baker from Natal is 

 closely related to the American T. montanum but scarcely 

 identical. Ail thèse species, T. erosum excepted, is unknown 

 to me. 



Below I give a key to ail the species known from the 

 African Islands in the Indian Océan, including also those 

 known from descriptions only (T. Barklyamim, T. Giesen- 

 hagenii, T. Hildebrandtii). 



1. Fronds peltate, 3 — 4 cm broad, closely appressed to 

 the soil T. Hildebrandtii Kuhn. 



— Fronds not peltate 2. 



2. Margins of frond ciliate; fronds small, entire 3. 



— Margins glabrous {Microgonium) 4. 



3. Spurious veins none T. BarJclyanum Bak. 



— Spurious veins numerous T. Giesenhagenii G. Chr. 



4. Intramarginal vein absent .... T. fulgens G. Chr. sp. n. 



— Intramarginal vein présent .... 5. 



5. Spurious veins continuous, rarely interrupted, united 

 with the distinct, continuous intramarginal vein ; veins 

 more or less flabellate; mouth of indusium dilated 



T. cuspidafum Willd. 



— Spurious veins interrupted, rarely united with the less 

 distinct, often flexuose intramarginal vein; veins pinnate; 

 base of frond cuneate 6. 



