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Zenodo
2025
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| Онлайн доступ: | https://doi.org/10.5281/zenodo.16897630 |
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- <p><i>Stigmatodactylus maraiparaiensis</i> S.F.Md-Isa & A.S.Rob., <i>sp. nov.</i></p><p>(Figs 1,2)</p><p>Type:— MALAYSIA. Borneo: Sabah, Ranau District: Mount Kinabalu, Marai Parai Plateau, 1,652 m a.s.l., emergent from leaf litter in damp humus layer amongst roots along small streams, 12 October 2023, <i>Md-Isa 00250</i>, (holotype: SNP 43737 + spirit collection).</p><p><i>Stigmatodactylus maraiparaiensis</i> is similar to <i>S. richardianus</i> (Table 1) but differs in having the callus adnate to lip for 2/3, longitudinally furrowed without raised apical margin and without lateral margin projections (vs. callus ±porrect, longitudinally canaliculate with raised lateral and apical margins, thus appearing narrowly cochleate, with a small projection on each lateral margin), column straight for ±1/4 its length then decurved throughout remainder, without a ventral keel (vs. straight for 2/3 then distally decurved, with basal ventral keel culminating in projection), dactyliform appendage reduced and inconspicuous except through dissection (vs. appendage conspicuous to naked eye), leaf apex rounded but apiculate at very tip (vs. apex subacute), tubers spherical (vs. rhizomatous).</p><p>Terrestrial herbs 5.0– 9.8 cm tall with a spherical tuber and few roots. Stem simple, erect, terete, green. Leaf single, cordate, basal lobes auriculate with a narrow sinus, distally rounded but apex apiculate, glabrous, green, 5.40 mm dia., margin entire, veins apically anastomosing. Inflorescence an erect raceme, 1–2(–3)-flowered, peduncle ca. 2.0–5.0 cm, rachis ca. 2.6–5.0 cm, pedicel 3 mm long, pedicels subtended by leafy bracts, 2–5 × 4–6 mm. Flowers resupinate, widely spreading, translucent. Dorsal sepal suberect to erect, linear, 3.05 × 0.7 mm. Lateral sepals descending, each 45° from vertical, linear, 2.6 × 0.5 mm. Petals linear, reflexed or spreading outward, 2.0 × 0.3 mm. Lip sessile to base of column, 2.0 × 2.5 mm, immobile, ±complanate but slightly furrowed along midline, cordate, not lobed to indistinctly trilobed, apex apiculate, margins erose-crenulate to subentire, glabrous. Callus 0.8 × 0.3 mm, adnate to lip for 2/3 its length, furrowed, margins entire without lateral margin projections, maroon. Column straight for ±1/4 its length then decurved through to apex, 1.50 mm long, ventral keel absent, green, based flushed in maroon, column apex shortly clavate, 1/3 of total column length, stigma 0.2 mm long, lingulate, dactyliform appendage reduced and inconspicuous except through dissection or perfused with solvent, anther bilocular. Capsule narrowly ovate, 5–12 mm long, 2–5 mm, 6-ridged. Seeds unknown.</p><p><b>Phenology:—</b> Flowered in October 2023. Though the plant produces a perennating tuber, it is not clear for how long each season plants remain in growth, nor indeed whether they are persistent over many years or relatively ephemeral; plants were not recorded on previous visits to Marai Parai by the third author in the May–June period.</p><p><b>Habitat:—</b> Terrestrial in montane forest among leaf-litter in deep shade. Noteworthy species in the area include <i>Tristaniopsis elliptica</i> and <i>Leptospermum recurvum</i> (both Myrtaceae).</p><p><b>Distribution:—</b> Only known from the Marai Parai Plateau, on the flanks of Mt. Kinabalu, Sabah, Malaysia. This area is well known for its ultramafic ecosystems and particularly its edaphically modified flora. It is worth noting that Wood <i>et al</i>. (2011) indicated that <i>S. lamrii</i> was sighted on Pig Hill by the late Anthony Lamb, but without a collection for this generally poorly documented genus, it is not possible to confirm whether this observation actually represents <i>S. lamrii</i>, <i>S. maraiparaiensis</i> or indeed a separate taxon entirely.</p><p><b>Etymology:—</b> Referring to the Marai Parai Plateau.</p><p><b>Proposed conservation status:—</b> The taxon satisfies the IUCN 3.1 Red List CR (critically endangered) criteria B2ab(iii,v)+D (IUCN 2012, 2024), being recorded only from Marai Parai where the single population is confined to an area of just a few square metres and comprises fewer than 50 mature individuals. The slopes of Mount Kinabalu are prone to periodic landslides because of erosion and earthquakes and a single stochastic event of this nature on Marai Parai could put both the extent of suitable habitat and number of mature individuals at risk of precipitous decline.</p><p><b>Notes:—</b> <i>Stigmatodactylus</i> has been recorded from Australia, China, India, Indonesia, Japan, Malaysia, New Caledonia, Philippines, Solomon Islands, Taiwan, Thailand and Vietnam (POWO 2024), but despite being widespread from eastern Asia into Oceania, the genus is, in the main, infrequently documented. This is presumed by the authors to be the result of a combination of factors, including: the diminutive stature of the plants; their unexceptional appearance in the sterile state; their relatively short and irregular flowering periods; the production of flowers with often cryptic colour in their favoured deepshade habitat amongst leaf litter; the apparently ephemeral nature of populations (Robinson <i>et al.</i> 2016); and probable bias against observations since many species occur at high elevation, infrequently accessed cloud forest locations, particularly in regions close to the equator. The notable exception is those species from eastern Australia and New Caledonia, at higher latitudes, where known populations occur at lower elevations closer to roads and tracks, making them commensurately more accessible and more frequently photographed. In Malaysia, just two localities have hitherto been documented to harbour <i>Stigmatodactylus</i> species: a peak in Kedah, Peninsular Malaysia, where <i>S. richardianus</i> occurs, and Mount Kinabalu, Sabah, from where <i>S. lamrii</i> was described (see Figure 3 for a distribution map of <i>Stigmatodactylus</i> in Southeast Asia). The description of <i>S. maraiparaiensis</i> brings the total number of <i>Stigmatodactylus</i> species for Malaysia to three and the total number of accepted species in the genus to 29.</p><p><i>Stigmatodactylus maraiparaiensis</i> appears superficially like four <i>Stigmatodactylus</i> species native to south-eastern Asia on account of their somewhat hyaline and variably pale green sepals and petals. In addition to <i>S. richardianus</i>, addressed in the diagnosis, the newly described taxon somewhat resembles <i>S. javanicum</i> (from Java), the otherwise turquoise-greenflowered <i>S. lamrii</i> (Mt. Kinabalu endemic), and <i>S. sikokianus</i> (southern China, Japan, Taiwan, Thailand and Vietnam). Nonetheless, <i>S. maraiparaiensis</i> can be reliably distinguished from these by the combination of its obviously cordate, sometimes indistinctly trilobed labellum with an apiculate apex, its straight, basally adnate, canaliculate callus that lacks a raised apical margin, lobes and lateral projections, its markedly decurved column that lacks any ventral keel or projection and its present but greatly reduced dactyliform appendage.</p><p>A presumed Mt. Kinabalu microendemic, <i>S. maraiparaiensis</i> is a notable addition to the orchid flora of this speciesrich biodiversity hotspot. The fact that the taxon has been documented for the first time from a relatively well-botanised location on the mountain demonstrates the value of periodic flora surveys to more effectively capture perennially emergent or ephemeral species at the fertile stage.</p>