Angraecopsis lemurelloides P.J.Cribb & Hermans, 2021

Hermans, Johan, Rajaovelona, Landy & Cribb, Phillip, 2021, New species in Orchidaceae from Madagascar, Kew Bulletin 76, pp. 39-56 : 43-44

Angraecopsis lemurelloides P.J.Cribb & Hermans sp. nov.

Type: Madagascar, Antsiranana Prov., Andapa, Doany, Anjialavahely , Ankarongameloka forest, 1546 m, epiphyte on tree, March 2006, Antilahimena & Tianina 4742 (holotype K! , isotypes P!, TAN!) .

http://www.ipni.org/urn:lsid:ipni.org:names:77214545-1

Arching to pendent epiphytic herb 15 – 21 cm long; roots basal, glabrous, greenish-white, 1 – 2 mm in diam. Stem woody, up to 15 cm × 3 – 4 mm, zigzag, flattened, the margins winged, carrying 12 – 17 leaves, pale green with the lower part somewhat corrugate and brown. Leaves alternate, coriaceous, flat with an indistinct central vein, lanceolate-linear, 6.5 – 8.1 × 0.5 – 0.8 cm, narrowing towards the apex, attenuate, the base subcordate, surface somewhat glossy, pale green. Inflorescences emerging from the leaf-axils along the entire length of the stem, sometimes several produced from the same axil, 5 – 8 cm long, with 3 – 7 flowers. Peduncle wiry, 3 – 5 cm, c. 0.5 mm in diam., with a short thin, brownish bract at the base peduncle, 1 – 2 peduncle sheaths c. 3 × 1 mm. Rachis loosely racemose, wiry, 3 – 5 cm, somewhat zigzag. Floral bracts amplexicaul, 3.1 – 3.8 × 1.1 – 1.4 mm, green becoming brown with age. Flowers small, c. 7 × 5 mm, yellowish-green. Pedicel and ovary turbinate, 9 – 12 × 1.3 – 1.6 mm. Dorsal sepal convex, ovate, acute, 2.1 – 2.5 × 1.9 – 2.2 mm. Lateral sepals partly fused to the petals at the base, broadly lanceolate, acuminate with the tip reflexed, 3.1 – 3.4 × 1.2 – 1.4 mm, margins recurved, the apex of the dorsal mid-vein mucronate before the apex of the leaf. Petals reflexed, ovate-triangular, acute, 1.4 – 1.7 × 1.5 – 1.7 mm, convex with a thickened mid-vein. Lip 3-lobed, 2.3 – 2.9 × 2 – 2.2 mm, the hypochile orbicular beneath with the obtuse lateral lobes partly enveloping the column, the epichile broadly ovate, concave, somewhat bullate with a few fine hairs at the base; s pur incurved below the flower, 4.9 – 5.4 × 0.6 – 0.8 mm, narrow at the opening, slightly thickened in the apical half. Column, fleshy, short, c. 1.6 × 1.5 mm; rostellum 3-lobed, wings sub-orthogonal, with an acicular median tooth; pollinia on separate viscidia, oblong, c. 1 mm long; anther cap elliptic, c. 0.6 × 1.1 mm. Seed capsule turbinate, c. 20 × 5 mm, green. Figs 3 , 4 .

RECOGNITION. Angraecopsis lemurelloides is recognised by the long zigzag flattened stem with lanceolatelinear leaves alternate along its length, small flowers on the upper third of the serial wiry inflorescences, and flowers with petals and sepals that are fused at the base and with a mucronate tip to the mid-vein, the roundly 3-lobed lip with a concave epichile with wiry hairs at the base and the lateral lobes enveloping the column and a short inflated spur.

It is very different in plant habit and flower morphology from Angraecopsis parviflora (Thouars) Schltr. ( Schlechter 1914: 601) , the only other Angraecopsis Kraenzl. ( Kraenzlin 1900: 171) recorded from Madagascar. That species has a stem that is always much shorter than the leaf, a lip with three distinct attenuate lobes and a slightly longer spur. In habit and inflorescence it somewhat resembles A. trifurca (Rchb.f.) Schltr. ( Schlechter 1915: 428) from the Comoros but it has a much longer stem, carrying leaves along its length, the flowers being about half the size, the spur much shorter and the lip very different (three distinct attenuate lobes in A. trifurca ). It is closest to Angraecopsis pobeguinii (Finet) H.Perrier (1941 : 81) from the Comoros in flower size and in having a lip with small rounded lateral lobes but the plant of A. pobeguinii is much smaller (3.5 cm long), the stem shorter (1 cm long), the leaves much smaller (c. 2 cm long), the spur is also much more clavate towards the apex.

DISTRIBUTION. Endemic to NE Madagascar.

SPECIMENS EXAMINED. MADAGASCAR. Anjialavahely, Ankarongameloka forest , 1546 m, March 2006, Antilahimena & Tianina 4756 (paratypes MO, P!, TAN!) .

HABITAT. Humid forest, epiphyte. Elevation c. 1550 m.

CONSERVATION STATUS. Angraecopsis lemurelloides is distributed in N Madagascar, in Doany, Sava region, Antsiranana. With the AOO estimated to be 4 km 2, one threat location identified and the number of mature plants, the species is assessed as Critically Endangered CR with criterion D.

FLOWERING TIME. March.

ETYMOLOGY. Refers to the similarity of the flowers to those of the genus Lemurella Schltr. ( Schlechter 1925: 366) .

NOTES. Morphologically the new species is somewhat ambiguous in its generic position. With a long stem, many wiry inflorescences and flowers with a threelobed lip with hairs at its base it resembles some species in the genus Lemurella and especially Lemurella culicifera (Rchb.f.) H.Perrier (1941 : 334) but it lacks the non-resupinate flowers, has more flowers and the opening of the spur is narrow (vs funnel-shaped). It illustrates that the generic circumscription of both these genera is somewhat uncertain and needs further research. As determined by Bosser (2007), it fits more easily in the genus Angraecopsis . This genus, somewhat diverse and containing a confusing variety of species, was established by Kraenzlin (1900), based on Angraecopsis tenerrima Kraenzl. from Tanzania. Schlechter (1914 & 1918a) extended the genus to seven species based on a spur with a narrow opening, entire side lobes of the lip and lip flat at the base, five being from mainland Africa and two from Madagascar, the Mascarenes and the Comoros. Perrier de la Bâthie (1941: 81) recognised five species in the Flore de Madagascar. Summerhayes (1951) in his revision of the genus recognised three sections: Angraecopsis , Cardiochilos and Coenadenium , mainly based on differences in the shape of the lip and column, with 14 species from the Afro-Madagascan region. Rasmussen (1978: 137) added further observations on the genus but doubted the generic and sectional circumscription. Recent molecular analyses by Martos et al. (2017) confirmed this view and proposed to restrict the concept of Angraecopsis to the species in section Angraecopsis , which includes all the species from the Madagascar region. The characteristics for the genus were summarised by Martos et al. (2017: 8) as: small to medium-sized plants with lateral sepals longer than the dorsal, a deeply three-lobed lip, a three-lobed glabrous rostellum with prominent lateral lobes and two pollinia each attached to a separate viscidium. Angraecopsis lemurelloides which is a relatively large plant with a long stem and roundly-lobed lip with hairs at the base only partly fits this definition but it does match it in the other aspects and also has the petals adnate to the lateral sepals as defined for the genus by Kraenzlin and Summerhayes. It is therefore placed in Angraecopsis but will remain a somewhat aberrant species.

Figures

Fig. 3. Angraecopsis lemurelloides. Photograph of the syntype: Antilahimena & Tianina 4756. PHOTO: © PATRICE ANTILAHIMENA. TROPICOS - MBG.

Fig. 4. Angraecopsis lemurelloides. A habit; B flower side view; C flower detail ¾ view, lateral sepal removed, showing lip; D dorsal sepal, inside; E lateral sepal & petal, above; F lateral sepal, underside; G front view lip, rostellum; H anther front view; J anther back view. Based on Antilahimena & Tianina 4742. DRAWN BY JULIET BEENTJE.