Disperis bathiei Bosser & la Croix, 2002

Croix, Isobyl la, Bosser, Jean & Cribb, Phillip J., 2002, The genus Disperis (Orchidaceae) in Madagascar, the Comores, the Mascarenes and the Seychelles, Adansonia (3) 24 (1), pp. 55-87 : 79-85

18. Disperis bathiei Bosser & la Croix , sp. nov.

Affinis Disperis masoalensi P.J. Cribb & la Croix sed foliis hastatis distincte petiolatis, inflorescentia 4-5- flora, petalis linearibus, labello carnoso trilobato, lobis laterilibus erectis pubescentibus lobo medio lanceolato pendenti glabro ornato bene distinguenda.

TYPUS. — Perrier de la Bâthie 1924bis, Madagascar, massif of Manongarivo, 1000-2000 m, May 1909 (holo-, P!, photo K!) . Known only from the type collection.

Terrestrial herb c. 17 cm high. Leaves 3, in upper half of stem, alternate, up to 3.3 × 1.8 cm, ovate, the lowest petiolate, the upper two sessile; petiole 2 mm long with a basal sheath 8 mm long. Inflorescence 5-flowered; bracts leafy, ovate to lanceolate, acute, up to 1.5 cm long. Flower colour not known; pedicel and ovary 12 mm long. Dorsal sepal 10 × 1 mm, linear; lateral sepals free to the base, 13-14 × 4.5-5.6 mm, obliquely elliptic, subacute, with a small spur in the basal half. Petals 10 × 2.5 mm, oblong, subfalcate, adnate to the dorsal sepal to form an elliptic, concave hood, rounded at the summit, 9.5-10 mm high, 6 mm wide. Lip with a linear claw, slightly reflexed at about 3.5 mm from the base and enlarged just below the bend, extending above the bend for 3.5 mm but divided at about halfway along into 2 branches, then sharply bent down to the front and bearing an obtuse, glabrous, linguiform, convex appendage 5.5 mm long. — Fig. 11.

DISTRIBUTION. — Madagascar; endemic. HABITAT. — In the understorey of humid forest at intermediate elevation.

This species has only been collected once. It resembles D. lanceana in the shape of the flowers and the morphology of the lip, but the appendage is completely glabrous and is borne on a glabrous stalk. The lateral sepals appear to be free almost to the base. But this character needs to be confirmed. On the label on the type specimen, PERRIER DE LA BÂTHIE commented that it approaches D. comorensis (= D. humblotii ), but in that species the terminal appendage of the lip is considerably smaller and bears a short, dense indumentum except on the basal extremity.

19. Disperis lanceolata Bosser & la Croix , sp. nov.

Affinis Disperis disciferae H. Perrier sed foliis multo reductis, inflorescentia 2-5-flora, galea longiora quam latiora, labello trilobo, lobo medio unguiculato ovato ad basin umbonato satis differt.

TYPUS. — Bosser 7951, Madagascar, Ambohitantely, district of Ankazobe, Apr. 1955 (holo-, P!, photo K!).

A very slender terrestrial herb 14-27 cm high. Stem slender violet. Leaves 2-3, alternate, sessile or rarely with a very short, 1 mm long petiole, the lowest leaf in the lower half of the stem, 1.8-3.6 × 0.7-1.5 cm, lanceolate to narrowly ovate, acute. Inflorescence 2-5-flowered; bracts lanceolate, acute, 4-6 mm long, leaf-like. Flowers rose pink, the petals striped with violet; pedicel and ovary 10-13 mm long. Dorsal sepal 7.5 × 1 mm, linear; lateral sepals 6-9 mm long, free more or less to the base, obliquely oblanceolate, with a distinct spur at about the middle. Petals 7.5 × 2 mm, obliquely oblong, subacute, the free margins undulate, adnate to the dorsal sepal and forming an oblong, concave hood 5.5-7.5 mm high, 2.5- 3 mm wide. Lip claw joined to the column at the base, the free part gradually enlarged to 2 papillose lobes, then with a narrow stipe 2 mm long ending in a suborbicular or elliptic appendage, 1.5-2 mm in diameter, papillose in the centre, with a protuberance where the blade joins the stipe. Rostellum with short arms. — Fig. 12.

DISTRIBUTION. — Madagascar; endemic.

HABITAT. — In humus in shade in moist forest, edge of forest in shade of small trees in deep leaf litter; 1200-2000 m.

MATERIAL STUDIED. — MADAGASCAR: Bosser 7951, forest of Ambohitantely , Ankazobe Distr., Apr. 1955 ( P!); Botoalina in Rés. Nat. 3758, Rés. Nat. no. 3, Ambatosoratra, Ambatondrazaka, 10 Apr. 1952 ( P!); J. & C . Hermans 13-5/10, Ambohitantely , Ankazobe Distr., 1450 m, May 2001 ( K!); Humbert 25754, massif of Marivorahona, SW of Manambato, high Mahavavy du Nord, Ambilobé Distr., 16-26 Mar. 1951 ( K!, MO, P!) .

This species recalls D. humblotii and D. saxicola in its habit. It is distinguished by its much smaller and narrower, sessile leaves and by the terminal appendage of its lip in the form of a flat elliptic or suborbicular plate having at its base a rounded protuberance. The lip appendage bears some resemblance to that of the African species D. togoensis , but the latter is a more slen- der plant with larger flowers and leaves, and with the lateral sepals joined at the base for a quarter to half of their length. It also resembles D. katangensis but that, too, has the lateral sepals partly joined.

20. Disperis masoalensis P.J. Cribb & la Croix , sp. nov.

Affinis Disperis bathiei Bosser & la Croix et D. ankarensi H. Perrier sed floribis majoribus, sepalis lateralibus fere ecalcaratis quam sepalo dorsali duplo longioribus, petalis undulatis, labello papilloso, lobis lateralibus incurvatis, lobo medio lanceolato deflexo satis differt.

TYPUS. — Schatz, van der Werff, Gray & Razafimandimbison 3380, Madagascar, Toamasina, Masoala Peninsula, 1-25 m, 31 Oct. 1992 (holo-, K!; iso-, MO, P!).

Slender terrestrial herb 8-12 cm tall. Stems slender reddish. Leaves 2, alternate, narrowly ovate, rounded at base, 25-32 × 11-12 mm, green, the lower with a short petiole 3-4 mm long. Inflorescence 1-2-flowered; bracts 7 mm long. Flowers pale pink inside, whitish tinged with pink on the outside; pedicel and ovary 12- 13 mm long. Dorsal sepal and petals forming a hood c. 10 mm long; dorsal sepal lanceolate, acute, 10 × 1-1.5 mm; lateral sepals deflexed, joined for about half their length, obliquely ovate, obtuse, 18 mm long, 20 mm wide across the middle where they are joined, shallowly concave at about half way along mid-vein. Petals obliquely ovate, obtuse to rounded at the apex, 10 × 6 mm, adnate to the dorsal sepal on the inner margin to form a hood over the column, undulate on the free margin. Lip fleshy, 3-lobed, 7 × 2.5 mm, papillose; basal lobes incurved, clavate; mid-lobe linguiform, deflexed, concave, tapering to blunt apex. Column erect, 2.5 mm long; rostellar arms porrect, clavate, 2-2.2 mm long; anther loculi parallel; pollinia clavate, sectile. — Figs. 7F , 13.

DISTRIBUTION. — Madagascar; endemic. HABITAT. — Growing in moss on top of boulders in river-bed; sea level- 25 m.

MATERIAL STUDIED. — MADAGASCAR: Labat & Poncy 3424, Tamatave Prov., Maroantsetra , Parc National Masoala, Andranobe, 0-10 m, 26 Oct. 2001 ( K!, MO!, P!, TEF, TAN) ; Lowry, Rakotozafy & Nicholl 4104, trail along Ampanga R., c. 5 km S of Hiaraka, E of Maroantsetra , NW coast of Masoala Peninsula, 13 Oct. 1986 ( MO, P!, TAN) ; Schatz, van der Werff, Gray & Razafimandimbison 3380, Toamasina, Masoala Peninsula, 1-25 m, 31 Oct. 1992 ( K!, MO, P!, TAN) .

Known only from three collections, this is a distinct species with one or two large pink and white flowers borne on a small plant. It is allied to D. bathiei and D. ankarensis . It differs from the former in its ovate, very shortly petiolate leaves, fewer, larger flowers in which the lateral sepals are fused almost to their mid-point and have the shallowest of spurs in the centre, broader undulate petals, and lip in which the mid-lobe is sessile and the side lobes are incurved and papillose rather than erect and pubescent. From the latter it differs in its larger flowers in which the scarcely saccate lateral sepals are much longer and larger than the dorsal sepal, the undulate petals, and papillose rather than villose lip.

21. Disperis bosseri la Croix & P.J. Cribb , sp. nov.

Affinis Disperis tripetaloidei Thouars sed foliis parvis perfoliatis, calcare sepalorum latiorum cylindraceo, labello glabro pandurato bene distinguenda.

TYPUS. — Bosser 10869, Madagascar, Ankaratra , road from Ambatolampy to Faratsiho, 2400 m, Feb. 1957 (holo-, P!, photo K!).

Slender terrestrial herb 15-18 cm high. Tubers 5-10 mm long. Leaves 3, alternate, more or less evenly spaced along the stem, 1-2 cm long, ovate to lanceolate, acute, suberect, sessile, clasping the stem. Inflorescence 1-2-flowered; bracts 8- 14 mm long, oblong, acute. Flowers pale pink; pedicel and ovary 9-15 mm long. Dorsal sepal c. 6 × 1 mm, linear; lateral sepals free to base, divergent, 6-7 × 3 mm, obliquely ovate, apiculate, with a prominent, obtuse spur 2-3.5 mm long, c. 1.5 mm wide. Petals c. 6 × 2.5 mm, spathulate, apiculate, adnate to the dorsal sepal and forming a concave hood c. 6 mm high and 6 mm deep. Lip with the basal part, ascending, obtriangular, 6-7 mm long, attached to the base of the column for 1-1.5 mm, terminal appendage ovate, 5,5-6,5 mm long, rounded or subtruncate at the base which is adorned with a small median subcircular, papillose lobule, obtuse and subtriangular at the tip; the upper face having in the basal half two slender erect wings with a thick and convex median zone between them, margins finely papillose towards the summit. Rostellar arms scarious, rigid, linear, a little dilated and rounded at the apex, 3-4 mm long. — Fig. 14.

DISTRIBUTION. — Madagascar; endemic. HABITAT. — Humid places, on steep slopes, in full sun light; 2400 m.

This species is only known from the type collection. It also resembles D. concinna Schltr. , known from South Africa and Zimbabwe, but the differences in the lip and appendage seem sufficient to recognise it as distinct .

22. Disperis falcatipetala P.J. Cribb & la Croix , sp. nov.

Affinis Disperis lanceolato Bosser & la Croix et D. tripetaloidei (Thou.) Lindl. sed sepalis latioribus usque ad medium adnatis, petalis falcatis, truncatis, labello trilobato lobis lateralibus carnosis villosis et lobo medio spathulato appendiculatoque satis differt.

TYPUS. — Malcomber, Hutcheon, Razafimanantsoa & Zjhra 1413, Madagascar, Antsiranana, Mangonarivo Special Reserve , Antsatrotro , E of summit, 1700-1730 m, 9 Apr. 1992 (holo-, MO!, photo K!).

A small, terrestrial herb up to 13.5 cm tall. Stem slender bearing three leaves in upper half. Leaves 3, alternate, suberect to spreading, ovate, obtuse, the largest 1.8 × 0.8 cm, the upper two progressively smaller, green with purple markings. Inflorescence terminal, c. 3-flowered; bracts ovate, subacute, 6 × 3 mm. Flowers clustered, white with purple dots; pedicel and ovary up to 10 mm long. Dorsal sepal concave, linearoblong, acute, 4 × 1mm, forming a hood with the petals. Lateral sepals deflexed, obliquely spathulate, obtuse or apiculate, united in basal half to form a narrow claw, 9.5-10 × 3.5 mm. Petals adnate to the dorsal sepal along inner margin, falcate, oblong, truncate, 5 × 1 mm. Lip 3-lobed, 3.5 mm long and wide when spread; side lobes fleshy, arcuate, truncate, villose in apical part; mid-lobe spathulate with an undulate margin to the apical lamina. Column short, 2 mm long including the clavate rostellar arms. — Fig. 15.

DISTRIBUTION. — Madagascar; endemic. HABITAT. — On a rotten branch on floor in ridge-top montane forest; 1700-1730 m.

Disperis falcatipetala is known only form the type collection which comprises two flowering plants. This small orchid is apparently allied to D. lanceolata Bosser & la Croix and to D. tripetaloides (Thou.) Lindl. It differs from the former in having slightly larger leaves, a shorter inflorescence, and flowers in which the lateral sepals are united to the middle to form a narrow claw, somewhat truncate petals, and a lip in which the side lobes are as long as the spathulate mid-lobe and villose. The latter differs in having larger more acute leaves and the flower which has free lateral sepals and a lip with a broad hairy base and a narrow, rather than spathulate mid-lobe. Disperis humblotii Rchb. f. has flowers that resemble those of D. falcatipetala but the former always has a petiolate lowermost leaf. It is also close to the tropical African D. johnstonii Rolfe but that usually has two larger leaves and flowers with a shorter broader claw to the united lateral sepals and a lip in which the mid-lobe is puberulous and has a central umbo.

Figures

Fig. 11. — Disperis bathiei: A, flowering plant; B, flower; C, dorsal sepal; D, lateral sepal; E, petal; F, column and lip, side view; G, lip; H, rostellum; I, pollinia granules. (Perrier de la Bâthie 1924bis P).

Fig. 12. — Disperis lanceolata: A, flowering plant; B, flower; C, hood; D, dorsal sepal; E, lateral sepal; F. petal; G, lip. (A-F, Botoalina, RN 3758, P; G, Bosser 7951, P).

Fig. 7. — Flowers of Disperis species: A, D. hildebrandtii; B, D. saxicola; C, D. discifera; D, D. oppositifolia var. oppositifolia; E, D. oppositifolia var. mascarenensis; F, D. masoalensis. (A, D, F, photos J.-N. LABAT; B, C, E, photos J. BOSSER).

Fig. 13. — Disperis masoalensis: A, flowering plant; B, hood, front view; C, dorsal sepal; D, lateral sepals; E, petal; F, column and lip, side view; G, column and lip, front view; H, column and lip, back view; I, lip; J, pollinarium. (Schatz, van der Werff, Gray & Razafimandimbison 3380, K).

Fig. 14. — Disperis bosseri: A, flowering plant; B, flower; C, hood, side view; D, dorsal sepal, side view; E, lateral sepal; F, petal; G, lip. (Bosser 10869, P).

Fig. 15. — Disperis falcatipetala: A, flowering plant; B, flower; C, dorsal sepal (dotted line shows where joined to column); D, lateral sepals; E, petal (dotted line shows where attached to column); F, column and lip, side view; G, column and lip, back view; H, lip. (Malcomber et al. 1413, MO).