Habenaria crocodilium Hermans, 2021

Hermans, Johan, Rajaovelona, Landy & Cribb, Phillip, 2021, New species in Orchidaceae from Madagascar, Kew Bulletin 76, pp. 39-56 : 47-49

Habenaria crocodilium Hermans sp. nov.

Type: Madagascar, Toamasina Prov., Andasibe, forest around Vakona Lodge , 950 m, Sept. 1996, Hermans 4880 (holotype K!) .

http://www.ipni.org/urn:lsid:ipni.org:names:77214548-1

Erect terrestrial herb 20 – 40 cm tall without the inflorescence, with two ellipsoid tubers, c. 2.5 – 3 cm long, hirsute, roots wiry, clustered around the base of the stem c. 3 mm in diam. Stem not branched, 10 – 30 × 0.5 – 0.8 cm with 3 – 4 leaf-like sheaths along its length dividing it into short segments, becoming progressively larger toward the top, 3 – 8 × 1 – 3.5 cm. Leaves spreading, 3 – 5, arranged spirally along the stem forming an apical crown, lanceolate, 7 – 18 × 1.2 – 2.8 cm flat, somewhat fleshy, attenuate, subcordate at the base, shortly petiolate, somewhat serrate at the margins, pale green, darker along the veins. Inflorescence terminal, c. 15 cm, laxly racemose with c. 15 flowers. Peduncle c. 10 cm, 2 – 4 mm in diam., with 1 – 2 ovate sheaths, attenuate, subcordate at the base, hirsute, c. 20 × 8 mm. Floral bracts lanceolate, conduplicate, attenuate, dentate to hirsute at the dorsal ridge and basal margins, 11 – 16 × 2.1 – 3.2 mm. Flowers evenly distributed along the rachis, spreading, overall c. 25 × 25 mm, all segments pale green becoming paler towards the centre, the veins a little darker, column white, pollinia yellow. Pedicel and ovary fusiform, sharply ridged, densely denticulate, pale green, 15 – 21 × 1.2 – 2.5 mm. Dorsal sepal cucullate, arching over the column, lanceolate, 10 – 12 × 4.5 – 5 mm, the exterior echinate along the mid-vein. Lateral sepals spreading, obliquely ovate, 11.2 – 11.6 × 6 – 6.2 mm, almost flat, the apex a little mucronate, the veins thickened. Petals bifid to the base, posterior lobe (11 – 12.1 × 1.1 – 1.4 mm) adnate to dorsal sepal, ligulatelinear, attenuate, anterior lobe (9.3 – 12 × 1.2 – 1.3 mm) spreading to curved. Lip 3-lobed, all lobes pendent — recurved, the mid-lobe more strongly recurved especially at the tip, linear falcate, attenuate, mid-lobe (11 – 14.2 × 0.7 – 0.9 mm), lateral lobes (15.7 – 14.3 × 1.1 – 1.4 mm); spur clavate, tubular in the basal half, thickened and laterally compressed in the apical half, 12.3 – 13.1 × 1.2 – 1.9 mm. Column c. 5 mm high, 9 mm long, anther loculi narrowly ovoid, anther channels distinctly up-curved, c. 6.7 × 0.3 mm, stigmatic lobes linear incurved, staminodes bilobed, verrucose, pollinarium c. 8 mm long. Figs 7 , 8 .

RECOGNITION. Habenaria crocodilium is distinct in being a tall plant with spirally arranged leaves forming an apical crown, having an inflorescence borne on a short peduncle, denticulate floral bracts and flowers that are large for the genus in Madagascar, with denticulate ovary ridges, bifid petals with equal lobes, a lip with three equal descending lobes, a slightly flattened clavate spur shorter than the pedicellate ovary, and long and strongly up-curved anther channels. Amongst the large and medium-sized-flowered species of Madagascar and mainland Africa it is somewhat similar in flower shape to H. beharensis Bosser (1969a: 293) , H. cirrhata (Lindl.) Rchb.f. ( Reichenbach 1865: 180) and H. clavata (Lindl.) Rchb.f. ( Reichenbach 1865: 180) but it is very distinct in its habit with its leaves borne along the stem (vs apical), and much smaller flowers (half the size) with a much shorter and differently shaped spur. It has a similar spur and anther-channel shape to H. cornuta Lindl. ( Lindley 1837: 208) but again differs by its distinct habit, smaller flowers and differently proportioned lip and petals. The short clavate spur is also found in H. cochleicalcar Bosser (1969a: 294) , and its flowers are also similar in size but the habit of H. crocodilium is different and the lobes of the petals and lip are of different proportions (unequal vs equal). It is similar in plant habit to H. tianae P.J.Cribb & D.L.Roberts (2008: 199) but its flowers are smaller, by at least 1, the spur much shorter (12 mm vs 3 12 cm) and the anther channels a different shape. None of the other species listed above have the pronounced echinate-denticulate ovary, floral bract and exterior of the dorsal sepal.

DISTRIBUTION. Known from two localities in Toamasina province, the type location in the eastern forest and another in NE Madagascar.

SPECIMENS EXAMINED. MADAGASCAR. Toamasina, Analanjirofo, Lohan'i Ambitsy forest , Makira, 808 m, July 2007, Antilahimena et al. 5672 ( TAN!) .

HABITAT. Humid evergreen forest, on riverbanks and wet areas. Elevation 800 – 950 m.

CONSERVATION STATUS. Habenaria crocodilium is distributed in E Madagascar, in the Alaotra-Mangoro and Analanjirofo regions, Toamasina province. Two threat locations were identified, although the two subpopulations are protected in Makira and Vakona lodge, the species habitat quality is continuing in decline due to shifting agriculture and forest logging. Recently, colonies in the type locality were destroyed by landslides. The species is therefore assessed as Endangered EN B1ab(iii) +2ab(iii).

FLOWERING TIME. July to September.

ETYMOLOGY. Referring to the type locality near a crocodile enclosure and the resemblance of the column and dorsal sepal to the head of a crocodile, plus the numerous teeth on the flowers and ovary.

NOTES. Habenaria Willd. ( Willdenow 1805: 44) is a genus of about 600 terrestrial orchids, widely distributed in tropical and subtropical regions of the Old and New World (Cribb in Pridgeon et al. 2001: 300). There are now a total of 48 Habenaria species recognised from the Madagascar, Mascarene and Comoro region, 33 of which are found on Madagascar. Twenty-eight Habenaria species are endemic to Madagascar.

Figures

Fig. 7. Habenaria crocodilium. A plant habit; B inflorescence and detail of flower. PHOTOS: MAG IZOUARD.

Fig. 8. Habenaria crocodilium. A habit; B flower; C bract, dorsal view; D bract, side view; E dorsal sepal, front view; F dorsal sepal, side view; G lateral sepal; H petal; J lip; K column and lip, side view; L column, from above; M column, side view. Based on Hermans 4880. DRAWN BY JUDI STONE.