Vrydagzynea suddeei Chuchuea & Seelanan, 2025

Chuchuea, Chanachon & Seelanan, Tosak, 2025, A new species of Vrydagzynea (Orchidaceae: Goodyerinae) from southeastern Thailand with field observations on its pollination biology, Phytotaxa 698 (1), pp. 15-27 : 17-22

Vrydagzynea suddeei Chuchuea & Seelanan , sp. nov. ( Figs. 2–3 )

Type: — THAILAND. Chanthaburi: Khlung District, Trok Nong Subdistrict, Sabab Mountain , 163 m, 26 September 2024, C. Chuchuea 789 (holotype BKF!; isotypes BCU!, BKF!) .

Diagnosis: — Vrydagzynea suddeei is most similar to V. deliana Smith (1920: 24) from Sumatra in terms of many flowered inflorescence, sparsely pubescent sepals, and the conspicuously bilobed spur apex. The new species can be distinguished from V. deliana by a labellum having entire apical margins, a minutely bilobed apex and papillae on the upper surface, and being devoid of longitudinal ridge (vs. erose apical margins, obtuse apex, no papillae, and a thickened longitudinal ridge running along the middle), ovary sparsely pubescent (vs. glabrous), a larger leaf which is 4.4–6.3 cm long, 1.7–2.7 cm wide (vs. 1.3–3.9 cm long, 1.1–1.6 cm wide) and leaf blade having greyish-green with one central longitudinal silver stripe (vs. greenish-brown with three reddish stripes).

Description:—Plants terrestrial, rhizomatous herbs; creeping stem green, terete, elongate, glabrous, rooting from nodes, (2–) 3–4 mm in diameter; nodes prominent; internodes becoming shorter towards distal part, 1–3.3 cm long; erect stem green, terete, elongate, glabrous, 10–14 cm tall. Leaves spiral, petiolate, glabrous on both sides, 7–12, crowded on the upper part of erect stems, greyish–green on upper surface with a central white stripe, dull grey-green on lower surface, margins with thin silver stripe; petiole canaliculate, base sheathing, 1–1.5 cm long (including sheath); lamina obliquely ovate to ovate–lanceolate to elliptic, apex acute, base cuneate, margin entire and slightly undulate, (4.4–)5– 5.8(–6.3) × (1.7–)2–2.4(–2.7) cm. Inflorescence erect, a raceme, ellipsoid to subspherical, 15–34-flowered; peduncle glabrous below, becoming more hairy towards the upper part, 1.2–2.8 cm long, 1.5–2.4 mm in diameter; peduncular bract 1–2, narrowly triangular or elliptic, apex narrowly acute, base sheathing, margin entire to slightly erose, 1- or 3- veined, glabrous on both sides, 0.8–1.4 × 0.2–0.4 cm; rachis with dense uniseriate, pilate glandular trichomes, 1.9–3.5 cm long, 1.5–2 mm in diameter; floral bracts green, narrowly triangular, apex narrowly acute, base sheathing, adaxially concaved, 1-veined, abaxial surface and margins covered with uniseriate, pilate glandular trichomes, gradually smaller in size towards apex of the inflorescence, (6.5–)7.5–8(–9) × (2–)2.7–3.6(–4) mm. Flowers resupinate, 5.3–6 mm long, scarcely opening. Sepals proximally green to brownish red, distally white and turning yellow when old, sparse glandular trichomes only on outer surface, especially near its base, thick; dorsal sepal lanceolate to narrowly oblong, boat-shaped, apex bluntly acute, margins at the middle involute and constricted, connivent with petals to form a hood, (4.1–)5–5.6 × (1.2–) 1.5–1.8 mm; lateral sepals obliquely ovate-lanceolate, apex bluntly acute, tapering towards apex, and hooded, margins involute, (5.3–)5.9–6.3 × 2.2–2.5 mm. Petals pale reddish-yellow, glabrous, narrowly ovate and oblique, boat-shaped, apex bluntly acute to subtruncate, margins adaxially concaved, (3.4–)3.7–4 × (1.2–)1.5–1.7(–1.9) mm. Labellum spurred, the lamina white to pale yellow, forming obtuse angle to the spur, ovate to oblong when not spread out, margins entire and involute, apex minutely bilobed and folded inwards, bluntly obtuse in outline, papillae only on the upper surface, underside convex, usually thick and fleshy near its base, (2.3–)2.5–3(–3.2) × (1.9–)2.1– 2.3(–2.5) mm; spur placed alongside the ovary, translucent, oblong, somewhat inflated in front, apex conspicuously bilobed, each lobe rounded, two stalked glands inside on the back wall, (3.4–)4.1–4.5(–5) mm long, 1.8–2(–2.4) mm in diameter at middle; stalk white, placed near the base of spur, 0.5–1 mm long, 0.2–0.5 mm in diameter; glands pendulous, pale to dark brown, prolate to sub-globose, placed near the middle of spur, 0.6–0.8 mm long, 0.4–0.5 mm in diameter. Column (1.8–)2.3–2.5 × (1.1–) 1.4–1.6 mm (including rostellum); stigma bipartite, flat, triangular, each lobe 0.6–0.8 × 0.4–0.8 mm; rostellum flat, apex detaching as a viscidium, 0.9–1.2 × 0.5–0.8 mm; pollinarium 1.5–2 × 1–1.3 mm; pollinia 2, yellow; operculum cordate, 1.4–1.8 × 1.1–1.5 mm; caudicle dry; viscidium 0.6–0.8 × 0.5–0.7 mm. Ovary and pedicel green, sparsely pubescent, twisted, (5.2–)6–6.7(–7) mm long, 1–1.7(–2) mm in diameter. Capsule conical, 6.5–7.2 mm long, 2.3–2.7 mm in diameter. Seeds numerous, narrowly fusiform, thin balloon-like seed coat, 0.77–1 mm long, 0.09–0.11 mm in diameter.

Distribution and Habitat: — Vrydagzynea suddeei occurs on sandy loam covered with decaying plant litter in damp areas along small streams with shallow running water in Sabab Mountain at an elevation of around 160 m above sea level, along the Trok Nong Nature Trail in NPNP, Chanthaburi Province ( Figs. 1A–B and 4A–C ). Vrydagzynea suddeei was found growing in the understory with Salacca wallichiana ( Arecaceae ), Donax canniformis ( Marantaceae ), Zingiber montanum ( Zingiberaceae ), Procris repens ( Urticaceae ), Elatostema latifolium ( Urticaceae ), Thismia mirabilis ( Thismiaceae ), Lomariopsis lineata ( Lomariopsidaceae ) and other plant species.

Phenology: — Vrydagzynea suddeei was collected with flowers in August–October ( Fig. 4D ), and infructescences were collected in October–November ( Figs. 4E–F ).

Etymology: —The specific epithet “suddeei ” honors Dr. Somran Suddee, a senior botanist at the Forest Herbarium, Department of National Parks, Wildlife and Plant Conservation, Ministry of Natural Resources and Environment ( Thailand), who has dedicated his entire life to the study of plant taxonomy and has made great contributions to the Flora of Thailand. He also inspired the first author in the field of plant taxonomy and encouraged him to explore the Trok Nong area.

Suggested Vernacular Name: — Vrydagzynea is locally known as “Ueang Pru” in Thailand.Therefore, we suggest the vernacular name “Ueang Pru Trok Nong” for V. suddeei , according to its type locality.

Taxonomic Notes: —In addition to Vrydagzynea deliana , V. suddeei is also similar to V. argyrotaenia Schlechter (1905: 84) from New Guinea and V. guppyi Schlechter (1919: 43) from Solomon Islands in having a conspicuously bilobed spur apex and papillae on the upper surface of labellum. However, V. suddeei can be distinguished from both species by having a 15–34-flowered inflorescence (vs. 1–4-flowered and 4–8-flowered inflorescence) and a sparsely pubescent ovary (vs. a glabrous ovary). Furthermore, V. suddeei differs from V. argyrotaenia by having larger leaves, 4.4–6.3 × 1.7–2.7 cm (vs. 1–2.5 × 0.6–1 cm). Moreover, V. suddeei differs from V. guppyi by having sparsely pubescent sepals (vs. glabrous sepals). Although Ormerod (1994) opined that V. guppyi is a synonym of V. argyrotaenia , no formal reduction has been published thus far. Therefore, we included both taxa in the comparison. More detailed morphological comparisons are given in Table 1.

publication.

When compared with the other three Vrydagzynea species in Thailand ( Seidenfaden, 1978, Pedersen et al. 2011), specimens in a vegetative stage are somewhat different. Namely, V. suddeei differs from V. albida in generally having shorter erect stems (10–14 cm vs. 11–32 cm), a central white stripe on greyish-green leaves (vs. uniformly shiny green), and acute leaf apex (vs. subacute to shortly subacuminate, often mucronate). Also, V. suddeei differs from V. tristriata in having a central white stripe on greyish-green leaves (vs. one to three pale colored stripes on purplish leaves). In contrast, V. suddeei is similar to V. lancifolia based on the presence of a whitish longitudinal stripe on greyish-green leaves (see Figs. 1–2 in Lim et al. 2014) and leaf shape, although V. suddeei has a lower leaf length-towidth ratio (2–2.7) than V. lancifolia (3–4). However, when flowering, V. suddeei can clearly be distinguished from all three species in Thailand by the presence of a conspicuously bilobed spur apex and a labellum with a minutely bilobed apex. This bilobed spur apex in V. suddeei is highly consistent and present in all flowers, even immature ones.

Representative Specimens Examined:— THAILAND. Chanthaburi: Khlung District, Trok Nong Sub-district, Namtok Phlio National Park , Trok Nong Nature Trail , 161 m, 21 August 2024, C. Chuchuea 697 ( BKF!) ; ibid., 161 m, 21 Aug 2024, C. Chuchuea 698 ( BCU!) ; ibid., 155 m, 22 Aug 2024, C. Chuchuea 699 ( BKF!) ; ibid., 140 m, 22 Aug 2024, C. Chuchuea 700 ( BKF!) ; ibid., 140 m, 22 Aug 2024, C. Chuchuea 701 ( BKF!) ; ibid., 163 m, 26 Aug 2024, C. Chuchuea 702 ( BCU!) ; ibid., 163 m, 26 September 2024, C. Chuchuea 787 ( BKF!) ; ibid., 163 m, 26 Sep 2024, C. Chuchuea 788 ( BKF!) ; ibid., 163 m, 26 Sep 2024, C. Chuchuea 790 ( BKF!) ; ibid., 163 m, 26 Sep 2024, C. Chuchuea 791 ( BCU!) ; ibid., 163 m, 26 Sep 2024, C. Chuchuea 792 ( BCU!) ; ibid., 153 m, 20 October 2024, C. Chuchuea 800 ( BKF!) ; ibid., 153 m, 22 Oct 2024, C. Chuchuea 801 ( BKF!)

Figures

FIGURE 1. Map of study site. A. Geographical distribution of Vrydagzynea suddeei. B. Panoramic overview of the Sabab Mountain. All were prepared and photographed by Chanachon Chuchuea.

FIGURE 2. Vrydagzynea suddeei. A. Habit. B. Inflorescent. C. Floral bract. D. Flower, side view. E. Flower, front view. F. Dorsal sepals, back and front view. G. Lateral sepals, back and front view. H. Petals, back and front view. I. Hood formed by the dorsal sepal and petals as a single structure J. Column, labellum, spur, and ovary, side view.K. Labellum, top view. L. Inside the spur, showing two stalked glands. M. Column, views from different sides. N. Operculum, back and front view. O. Pollinarium.P. Infructescence. Q. Seed.All were illustrated by Chanachon Chuchuea, A.–O. from holotype (C. Chuchuea 789), P–Q from C. Chuchuea 801.

FIGURE 3. Vrydagzynea suddeei. A. Habit. B. Inflorescence. C. Floral bract, back and front view. D. Flower, side view. E. Flower, front view. F. Dorsal sepal, back and front view. G-H. Lateral sepals. I-J. Petals. K. Labellum, top view. L. Close-up of papillae on labellum. M. Apex of labellum, showing a minutely bilobed apex. N. Inside the spur, showing two stalked glands. O. Column, labellum and spur, side view. P. Column, views from different sides. Q. Operculum, back and front view. R. Pollinarium, views from different sides. S. Distal portion of infructescence. T. Seeds. All were photographed by Chanachon Chuchuea.

FIGURE 4. Ecology and habitat of Vrydagzynea suddeei. A. Plants species grow with V. suddeei (red arrow): DC, Donax canniformis; ZM, Zingiber montanum; SW, Salacca wallichiana. B. Ecology of V. suddeei C. A population of V. suddeei (red arrow in A.) in August 2024. D. Inflorescence in September 2024. E. Young infructescense in October 2024. F. Mature infructescense with opening capsules in November 2024. All were photographed by Chanachon Chuchuea.