A new species and a change of status in Ophioglossum ( Ophioglossaceae : Pteridophyta ) in Africa

A new species, Ophioglossum gracile Pocock ex J.E. Burrows, is described from South Africa. A lectotype is chosen for O. vulgatum var. kilimandscharicum Hieron. and its status upgraded to a subspecies.

Within the circumscription of her original taxon, Pocock included two collections from the same locality near Grahamstown in the eastern Cape which most resemble O. vulgatum subsp.africanum.However, since I (senior author) have not examined the spores from this population, I cannot be certain of its identity.From the collection data, it seems that O. gracile is restricted to sandstones of the Table Mountain Series in ericoid scrub (fynbos) on moist soils.A collection from the Cedarberg (Esterhuysen 7334) was made on a 'damp spot at the base of a shale band'.The type collection was made on 'shal low soil on the banks of a small stream .... in shade of pines'.Collections have been recorded in January, February, April, May, June, August, November and December, indicating that this species may be evergreen in suitably moist situations.Its distribution falls within the winter rainfall area which receives most of its rain from May to September.
Although O. gracile shares the same phytogeological association as O. bergianum, there is no record of the two species growing in mixed communities.Although Hieronymus designated no type specimen for his taxon (Engler 1895), all his new fern taxa from that expedition appear to have been collected by Volkens in 1893.Engler also visited Kilimanjaro in the previous year v # : A * * (Gillett 1962) but since Engler mentions Volkens' collect ing locality (Kifinika Volcano) in a subsequent account of the East African Ophioglossum (Engler 1908), it is likely that Volkens is the original collector of this taxon.A search for the type material in Berlin revealed that all pre-World War II material of Ophioglossum was destroyed (R.J. Johns pers.comm.).We can therefore assume that, if the specimen from which Hieronymus described the variety was in Berlin, it no longer exists.
There is, however, a collection made by Volkens on that expedition from the Kifinika Volcano, Kilimanjaro in the British Museum which is almost certainly isotypic.On the assumption that the Berlin material was destroyed and since no type was designated by Hieronymus, the sheet of Volkens 1161 in BM is designated as the lec totype.
Hieronymus distinguished his variety on the basis of the plants having 'leaves nearly always in pairs, the sterile lamina obovate or elliptic (max.30 x 17 mm), obtuse or slightly acute, spores 36-44 (im broad, areolae 2-4 (im wide'.The six collections seen that match the type specimen, differ from typical O. vulgatum.However, oc casional trophophores within variable populations of nor mal O. vulgatum match subsp.kilimandscharicum quite well.Conversely, no trophophores on the collections of subsp.kilimandscharicum resemble those of typical O. vulgatum. In addition, spores from the Natal and Transvaal col lections reveal a morphological pattern distinct from both typical O. vulgatum and subsp.africanum (Figure 2D).The spore muri frequently coalesce into large flattened areas and the lumina are correspondingly smaller and more widely separated.A specimen from Zaire (Lebrun 6016, Figure 2C) displays similar spore sculpturing and trophophores which match the Volkens collection.If these three collections belong to the Kilimanjaro taxon, then the spore pattern is distinct and constant.The trophophores are also subtly different from the typical plants in that they are broader, have a rounder apex and a thinner tex ture.
Very little is known of the ecology of this subspecies.The Kilimanjaro specimens were both collected at 2 800 m but no ecological data were given.The Drakensberg collection was made in burnt marsh under Miscanthus (Poaceae).The Transvaal collection was made at 1 645 m in submontane grassland, growing under Helichrysum (Asteraceae) bushes.As the subspecies is presently known, it is an afromontane taxon and could be expected from the Zimbabwe/Malawi gap which currently exists.