Eria dacrydium var. cornuta Aver. & Vuong

Averyanov, Leonid V., Nguyen, Van Canh, Vuong, Truong Ba, Nuraliev, Maxim S., Nguyen, Khang Sinh, Maisak, Tatiana V., Yudova, Daria A., Saidov, Nikita T., Nguyen, Cuong Huu & Nong, Duy Van, 2024, New orchids in the flora of Vietnam VIII (Orchidaceae: Epidendroideae, tribes Malaxideae, Neottieae and Podochileae), Phytotaxa 658 (1), pp. 1-49 : 38-40

Eria dacrydium var. cornuta Aver. & Vuong , var. nov.

( Fig. 18 & 19A–C )

Diagnosis: —The new variety differs from the type variety in the lip bearing at its base two prominent, forward directed, acute, glabrous horns.

Type: — VIETNAM. Lam Dong Province: the border of Lac Duong and Dam Rong districts, Bidoup-Nui Ba National Park, mountain evergreen broad-leaved and mixed forest (with Pinus kesiya ) at elevation 1600–1800 m a.s.l., epiphyte on tall mossy tree, flowers white, locally common, 21 February 2023, L. Averyanov, Nguyen Van Canh, Nong Van Duy, AL 2103 (holotype LE 01168157! https://en.herbariumle.ru/?t=occ&id=170355, isotype LE LE 01168156! https://en.herbariumle.ru/?t=occ&id=170354, photos of plant used for preparation of the type herbarium specimen LE LE 01123853 https://herbariumle.ru/?t=occ&id=165222, drawing LE LE 01124201 https://en.herbariumle.ru/?t=occ&id=171480).

Etymology: —The variety name refers to the horn-like calli at the lip base.

Description:—Herb epiphytic, with several stems densely clustering on short plagiotropic rhizome. Stem pale yellowish green, erect, terete, narrowly clavate, (4.5)5–10(12) cm long, (0.5)0.6–0.8(1) cm in diameter in the broadest part, glabrous, with 3–4 short internodes at base and 2–3(4) short internodes at apex, median part of stem consisting of 1–2(3) internodes. Leaves (1)2–3, at stem apex, subsessile, grassy green, lanceolate, rigid, (3.5)4–8(9) cm long, (4.5)5–8(9) mm wide, acute, glabrous. Inflorescences 1–3 at stem apex, axillary, 3–5 cm long, glabrous; peduncle (1.2)1.5–2(2.2) mm long, with 2 small sterile bracts at base and 1 yellow-green, ovate bract at middle, as large as floral bracts; rachis yellow-green, about 1 mm long, 2-flowered; floral bracts yellow-green to yellow, narrowly ovate to ovate, acute, conduplicate, without distinct venation, (0.8)1–1.2(1.3) cm long, 4–7 mm wide. Pedicel and ovary yellow-green to yellow, (1.2)1.4–1.8(2) cm long, glabrous. Flowers widely opening, white, lip with light brownish apex of epichile, brownish keels and horns placed on disk. Median sepal narrowly ovate, obtuse, (11)12–14(15) mm long, (5)5.5–6(6.5) mm wide, with 7 veins, glabrous. Lateral sepals triangular narrowly ovate, obtuse, strongly oblique, (12)13–14(15) mm long, 5–6 mm wide, glabrous, with 5–7 veins, connate with column foot forming short sub-globose mentum (3.8)4(4.2) mm across. Petals oblong rectangular, with almost parallel margins, slightly oblique, recurved, (12)13–14(15) mm long, 3.8–4.2 mm wide, shallowly emarginate at apex, glabrous, with 5 veins. Lip 3- lobed, (8)8.5–9.5(10) mm long, (6.5)7(7.5) mm wide (at the widest part), attached to column foot by short broad claw 1–1.2 mm long; side lobes erect, narrowly ovate, round at apex, 6.5–7 mm long, 2.5–3 mm wide, glabrous; median lobe small, 0.8–1 mm long, 1.4–1.6 mm wide, circular or broadly ovate, truncate, strongly down curved, densely papillulate inside and glabrous outside; disk at base with 2 prominent, forward directed, acute, glabrous horns 0.8–1 mm long; disk in center with 2 fleshy, glabrous lateral keels and with 1 fleshy median densely yellow strigose keel near disk apex. Column stout, erect, 6.5–7 mm tall, conduplicate, glabrous, laterally with narrow wings, near apex with small concave obovate stigma; column foot upcurved, 2.8–3 mm long, forming almost right angle with column, at apex with prominent, obscurely triangular, papillose knob. Anther cap white, 1.4–1.6 mm tall, 0.8–1 mm wide, helmet-shaped, glabrous, at sides with 2 rounded lateral valves; pollinia 2, narrowly ovoid, dull yellow, 0.6–0.7 mm long. Fruits unknown.

Ecology and phenology: —Clustering epiphyte. Evergreen broad-leaved and coniferous montane forest on granite at elevation of 1500–1800 m a.s.l. Occasional. Flowers in December–February.

Distribution: —Endemic to S Vietnam: Lam Dong Province (Bidoup-Nui Ba National Park and Da Lat City area).

Conservation status: — Eria dacrydium var. cornuta was observed in two locations in a highland area of Langbian Plateau. Both localities are in Lam Dong Province, and one of them is within the legally protected territory of Bidoup-Nui Ba National Park. This National Park, however, is partly influenced by deforestation, notwithstanding its protected status. Hence, we preliminarily estimate the conservation status of the new variety as Near Threatened (NT).

Notes: — Eria dacrydium var. cornuta differs from the quite variable type variety (drawings of which are presented by Seidenfaden 1992: 181, fig. 116, plate 12с) in the lip bearing at the base two prominent, forward directed, acute, glabrous horns 0.8–1 mm long (vs. base of lip without any ornamentation or with two low indistinct inflations). The lateral keels at the disk center in both varieties are similarly glabrous.

Additional specimen studied:— VIETNAM. Lam Dong Province: forest around Da Lat City, 9 January 2020, Truong Ba Vuong & Ngo Quang Dang, BV 842 (photos LE LE01124203 https://en.herbariumle.ru/?t=occ&id=171481).

Figures

FIGURE 18. Eria dacrydium var. cornuta. A. Flowering plant. B. Floral bracts and flower.C. Flattened column, median sepal and petals. D. Flattened column foot, lateral sepals and lip. E. Flattened lip and distal half of column foot, adaxial side. F. Flattened lip, abaxial side. G. Column and lip, side view. H. Lip, sagittal section. I, J. Column, front and side view. K. Anther cap, front and half-side view. Drawn by L. Averyanov and T. Maisak from the type specimen L. Averyanov et al., AL2103.

FIGURE 19. A–C. Eria dacrydium var. cornuta. Photos by L. Averyanov from the specimen L. Averyanov et al., AL2103 (A, B) and by Truong Ba Vuong from the specimen Truong Ba Vuong Dang, BV842 (C). D–F. Phreatia sulcata. Photos by Nong Van Duy from the specimen N.V. Duy 578 (D, E) and J. Leong-Škorničková from specimen Leong-Škorničková s.n. (F). Photo correction and design by L. Averyanov.