Pronephrium

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Pronephrium

Distribution

Asia-Tropical: India present, Ceylon present, New Hebrides present, North Queensland present, Pacific: Fiji (Fiji present), S. China present, Solomon Islands present
India&Ceylon; from S. China southwards throughout Malesia; North Queensland; Solomon Islands, New Hebrides, Fiji; c. 68 species, of which 12 not Malesian.

Taxonomy

Christensen () accepted Abacopteris Fee (which he included in Dryopteris) as published in 1843, but that publication consisted of the generic name only with no description. Ching gave generic status to Abacopteris, and cited Aspidium lineatum Bl. as type, but Fee did not mention that species when the generic name was validly published by him in 1852; he then listed Pronephrium Presl as a genus not adopted, as he had seen none of the species (p. 358).
Pronephrium Presl (1851) comprised four species, which I discussed in 1969, citing P. lineatum (Bl.) Presl as type and accepting the Statement by Mettenius and Christensen that the second species P. affine (Bl.) Presl was not distinct from the first. Subsequently (Holttum 1971) I examined the types of both of Blume's species and found them to be quite distinct from each other. The third of Presl's species is here named P. rhombeum; the fourth (P. lastreoides Presl) is here transferred to Sphaerostephanos.
Presl's most distinctive character is dimorphism of fertile and sterile fronds; this is doubtfully true of P. lineatum (the fertile frond of the type is not fully expanded) but is true of species 2 and 3. Fee distinguished Abacopteris mainly by subentire pinnae with meniscioid venation but the excurrent veinlets not free, and indusiate sori. Ching (1938) extended it to admit species in mainland Asia with exindusiate sori and typical meniscioid venation; he also cited absence of sinus-membranes as a generic character, but short membranes are often present (the line of distinction is not a sharp one). Christensen (1934) had already added species from Malesia as Dryopteris sect. Abacopteris. In 1971 and 1972, under the earlier name Pronephrium, I accepted the generic concepts of Ching and Christensen, adding the character absence of reduced basal pinnae, and divided the whole into three sections: Pronephrium, Dimorphopteris and Grypothrix. But some of the species then placed in sect. Pronephrium have resemblances to species in sect. Dimorphopteris and some to species in sect. Grypothrix. I here attempt to adjust this Situation by re-arranging the species in two subgenera Pronephrium and Menisciopsis. Haplodictyum Presl (which I treated as a separate genus in 1971) is included in sect. Pronephrium. But though sections Dimorphopteris and Grypothrix, as re-arranged, appear to be natural groups, the other two sections are probably not; problems of relationships are discussed under the sections.

Cytology

Chromosome number 36; 10 species investigated, of which P. pentaphyllum, P. peltatum var. peninsulare, P. womersleyi and P. triphyllum are tetraploid.

Citation

Presl - in Kalikasan. 1973: 59
Presl - in Blumea. 1972
Holttum - in Novit. Bot. Inst. Bot. Univ. Carol. Prag. 1969: 48
Ching - in Bull. Fan Mem. Inst. Biol. Bot. 1938: 230
Presl - in Blumea. 1971: 34
Holttum - in Rev. Fl. Malaya. 1955: 285
Ching - in Sunyatsenia. 1940: 251
Fee - in Acta Phytotax. Sinica. 1963: 331
Copel., Fern Fl. Philip. 1960: 377
Holttum - in Blumea. 1971: 37