Disperis Sw. Kongl. Vetensk. Acad. Nya Handl. 21: 218 (1800); Schlechter, Bull. Herb. Boiss. 6: 911 (1898).
Dryorkis Thouars, Nouv. Bull. Sci. Soc. Philom. Paris 1: 316 (1809).
Dryopeia Thouars, Orch. Iles Afr., 1er tableau a, t. 1-3 (1822) [Dryopria]; A. Richard, Monog. Orch. Ilesde France et Bourbon: 35 (1828), Extr. Mém. Soc. Hist. Nat. Paris 4.
The genus Disperis was established by Olof Swartz in 1800. The name comes from the Greek words dis (two) and pera (wallet, pouch), referring to the saclike spurs on the lateral sepals of most species.
Small, erect terrestrial, lithophytic or rarely epiphytic herbs with small tubers. Stems with 1 to several cataphylls at the base. Leaves 1 to few, opposite or alternate, sometimes with coloured veins, sometimes absent. Inflorescence racemose or one-flowered. Flowers small, white, yellow, green, pink, lilac or magenta purple. Bracts leaf-like. Dorsal sepal forming with the petals an open or elongate hood, concave or spurred. Lateral sepals free or partly adnate, each with a sac-like spur in the middle or near the inner margin (spur lacking in a few species). Petals hyaline, entire, adnate to the dorsal sepal to form the hood. Lip usually hidden within the hood, often complex, the claw joined to the face of the column and rising above it, curving into the hood or spur, often dilated into a smooth or papillose limb and usually bearing an appendage which varies greatly in shape from species to species. Column complex; rostellum large, 2-lobed, produced in front into two rigid cartilaginous arms with viscidia at their apices; anther loculi distinct, parallel but often well separated; pollinia granules secund, in a double row along the edge of the flattened caudicles; staminodes present in some species; stigma bilobed, the lobes on the rostellum, on either side of the adnate claw of the lip. Capsules cylindrical or ovoid, ribbed, usually developing rapidly, sometimes before the flower has faded.
All species of Disperis are deciduous, dying back below ground during the resting season—usually the winter, except for species from the winter rainfall area of South Africa. They like a free-draining but humus-rich terrestrial mix in a shallow pan as their root system is not extensive. Intermediate temperatures suit most species. The tropical African species are almost all forest or woodland plants, growing in heavy shade, but some of the South African species grow in open grassland. Humidity should be high during the growing season, and an occasional Watering should be given even in the resting season, as the small tubers can easily dry out too much and shrivel. Although not showy, they are appealing little plants and are attractive when several plants are grown together in a pan. Only a few seem to be in cultivation, although many others would be well worth growing, particularly those with attractive leaves.
Disperis are small herbaceous orchids, usually terrestrial but occasionally lithophytic or lowlevel epiphytes. Most are shade dwellers, growing in humus in forest and woodland, but a number of species grow in open grassland. Many are rather insignificant plants with fairly short-lived flowers, and they are almost certainly overlooked and under-recorded.
Disperis is a genus of about 80 species occurring in tropical and South Africa, Madagascar, the Comoro Islands, the Seychelles, the Mascarene Islands, India and the Malay Archipelago East to New Guinea. The greatest diversity is in tropical and southern Africa where more than three-quarters of the species are found. Sixteen species were recorded from Madagascar and the adjacent islands by Perrier De La Bâthie (1939), while 17 were reported from Madagascar by Du Puy et al. (1999).
Classification and Phylogeny:
Despite the great morphological diversity in the genus Disperis, two distinct clades were distinguished in the cladistic analysis of Manning & Linder (1992), based primarily on characters of the lip and appendage, and on pollen sculpturing. These are formally recognised here as the subgenera Dryorkis and Disperis.This classification differs sharply from the sectional classification of Schlechter (1898) who recognised two groups based on the arrangement of the foliage leaves.
This classification was obviously artificial, even to Schlechter himself (Schlechter 1898: 913). Within the two subgenera recognised here, several groups of similar and apparently closely related species can be identified. The groups that we (Kurzweil & Manning) recognise within subgenus Dryorkis are based on inferred morphological synapomorphies, while those within subgenus Disperis are derived largely from the clades retrieved by the morphological analysis of Manning & Linder (1992).
Disperis subgen. Dryorkis (Thouars) Kurzweil & Manning, stat. nov.
Disperis Johnstonii Group
Glabrous herbs. Leaves normally alternate. Tepal hood shallow or deep, lateral sepals frequently joined at base or more extensively; lip appendage mostly with erect, ascending or horizontally reflexed processes, usually pubescent throughout, blade normally with callus, with pronounced and elongate stalk, rarely stalk short and insignificant. Rostellum arms straight, linearspathulate,erect or slightly twisted outwards.
Disperis Oppositifolia Group
Glabrous herbs with opposite leaves. Hood shallow or deep, lateral sepals free or joined in their lower part; lip appendage of two forwardcurved, reflexed or decurved narrow processes, usually pubescent throughout, blade narrowly triangular or lorate, unstalked and without an apical callus. Rostellum arms simple where known.
Disperis Anthoceros Group
Glabrous herbs. Leaves normally opposite or subopposite. Hood deep or with pronounced spur, petals frequently with large basal anterior lobe and therefore appearing bilobed, lateral sepals free or extensively fused; lip claw mostly very long and slender, blade simple and ecallose,often surrounded by hairs, appendage mostly as two pendent or forward-curved and deeply bifurcate lobes, rarely of many pendent lobes or entire and apically dentate. Rostellum arms linearspathulate, erect or suberect, usually elongate and only rarely short (D. nemorosa); stigma lateral, mostly narrowly lanceolate at base of rostellum arms.
Disperis Pusilla Group
Small, mostly hairy or glandular plants. Leaf solitary. Median sepal linear or narrow, hood shallow or deep, lateral sepals free; lip with two-lobed appendage made up of triangular and deflexed lobes.
Disperis. subgen. Disperis, subgen. nov.
Disperis Micrantha Group
Almost always glabrous herbs. Leaves two, mostly alternate, rarely opposite or absent. Hood deep or spurred, lateral sepals free or fused at very base; lip claw weakly or extensively fused with gynostemium, blade flexed forward, flap-shaped or triangular, flat or convex, small in relation to appendage. Rostellum arms short and twisted outwards.
Disperis Cardiophora Group
Glabrous herbs. Leaf one, either basal or halfway up stem. Median sepal ovate or lanceolate, hooded, laterals free; lip claw slightly recurved, blade triangular or lorate, slightly convex, appendage oblong or triangular.
Disperis Thorncroftii group
Glabrous herb. Leaves two, alternate. Median sepal lanceolate and deeply hooded, laterals free; lip claw erect and fused with gynostemium, blade oblong with tapering tip, slightly convex, appendage oblong, reflexed.
Disperis Capensis group
Hirsute herb. Leaves two, alternate. Median sepal ovate and deeply galeate, laterals free, all three with long caudae; lip claw reflexed but soon curved forwards, terminating in a tapering lorate blade, appendage lorate.
Disperis Bolusiana group
Small hairy plants. Leaves two (rarely three), alternate. Median sepal ovate, forming a sac or hood, lateral sepals free; lip claw weakly or not at all fused with gynostemium, blade triangular, lorate and slightly concave or forming a cup together with base of appendage, appendage lorate, rarely absent (Disperis decipiens).
Disperis Wealei Group
Glabrous or rarely weakly hairy (Disperis cooperi) plants. Leaves 2-5, alternate. Median sepal mostly ovate to lanceolate and hooded, hood shallowly or deeply saccate, lateral sepals free; lip blade elongate and somewhat boatshaped, at base marginally fused to the entire lip appendage to form a concave structure, rarely (D. oxyglossa, D. tysonii) fusion absent or weak, blade always with verrucose elaiophores. Rostellum arms usually twisted outwards at tips.
Bibliography and References:
Hubert KURZWEIL & John C. MANNING 2005 A synopsis of the genus Disperis Sw. (Orchidaceae) ADANSONIA, sér. 3 • 2005 • 27 (2) : 155-207
Kurzweil H, Linder HP, Stern WL, Pridgeon AM. 1995 Comparative vegetative anatomy and classification of Diseae (Orchidaceae). Bot. J. Linn. Soc. 117. 171-220.
Kurzweil H, Manning JC. 2005 A synopsis of the genus Disperis Sw. (Orchidaceae). Adansonia 27. 155-207
La Croix I, Bosser J, Cribb PJ. 2002 The genus Disperis (Orchidaceae) in Madagascar, the Comores, the Mascarenes and the Seychelles. Adansonia 24. (1): 55-87 (2002)
LA CROIX I. 1988. — A natural hybrid in Disperis. Orchid Rev. 96: 361-362.
Linder HP, Kurzweil H. 1994 The phylogeny and classification of the diseae (Orchidoideae: Orchidaceae). Ann. missouri Bot. Gard. 81. 687-713.
Stewart J. 1981 Orchids of Africa: the dainty Disperis species of South Africa. Amer. Orchid Soc. Bull. 50. (8): 912 - 919 (1981)
Thomas S. 1996 A visit to Irian Jaya. Orchid Rev. 104. (1210): 231-234 (1996)
VERDCOURT B. 1968. — African orchids XXXI: new taxa of Disperis from East and Central Africa. Kew Bull. 22: 93-99.
Verdcourt B. 1976 Three noteworthy species of Disperis (Orchidaceae) unrecorded for East Africa. Kew Bull. 30. (4): 603 - 606 (1975 publ. 1976)
Verdcourt B. 1977 A new species of Dispersis (Orchidaceae) from Zambia. Kew Bull. 32. (1): 9 - 11 (1977
Verdcourt B. 1986 A key to the East African species of Disperis (Orchidaceae) with two new species. Kew Bull., 41. (1): 51-57 (1986)