Research Article |
Corresponding author: Siddharthan Surveswaran ( siddhus@gmail.com ) Academic editor: Vincent Droissart
© 2017 Siddharthan Surveswaran, Pankaj Kumar, Mei Sun.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Surveswaran S, Kumar P, Sun M (2017) Spiranthes himalayensis (Orchidaceae, Orchidoideae) a new species from Asia. PhytoKeys 89: 115-128. https://doi.org/10.3897/phytokeys.89.19978
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Spiranthes himalayensis is described here as a new species based primarily on molecular phylogenetic evidence followed by morphological comparison with other Asian Spiranthes species. It is distributed widely from southern India to tropical China. Phylogenetic analysis shows its close affinity to S. nivea which is endemic to Taiwan. Morphologically, the new species looks close to S. sinensis and S. hongkongensis. S. himalayensis is an allogamous species which can be differentiated from its allies on the basis of pubescent plant body, floral bract longer or of the same length as that of ovary, petals with blunt apex, labellum width around hypochile same as the width of epichile, epichile widely flabellate or semi-tunicate, column length equal to or more than 1.5mm, clavate operculum attached to the column on the broader part by an arm-like extension emerging from the upper part of column and a well developed rostellum partitioning the stigma and pollinarium.
Karnataka, Manipur, Orchid, Spiranthes hongkongensis , Spiranthes nivea , Spiranthes sinensis , Tamil Nadu, Yunnan, India, China
Spiranthes
While sampling Spiranthes in an aim to study the evolution and phylogeography of the genus in Asia, a white-flowered pubescent Spiranthes was discovered, which, based on DNA studies, was found to be distinct with respect to other known Spiranthes species (Fig.
Bayesian phylogenetic tree indicating Spiranthes himalayensis Survesw., Kumar & Mei Sun sp. nov. Sequences generated for this study are indicated in bold, specimen identification numbers and area of collection are indicated beside the species names. Bayesian probability supports are indicated at the nodes.
Morphological observations of the new species were carried out based on living plants as well as dry specimens. Measurements were made using a ruler and a micrometer. Both herbarium and fresh specimens were examined under a stereo dissecting microscope and photographs were taken with a Nikon SMZ16 stereomicroscope connected to a digital camera.
A combined dataset of nuclear ITS, chloroplast trnL-trnLF intron/intergenic spacer, trnS-trnG intergenic spacer and maturase K (matK) sequences were used for the analysis (Table
INDIA. Manipur: Ukrul district, Imphal-Jessami road, found on a paddy field on the way to Ukhrul town from Imphal, 1 May 2016. S. Surveswaran 1 (HJCB 1001) (holotype JCB!) (specimen id M1 in DNA based phylogeny, Fig.
Spiranthes himalayensis Survesw., Kumar & Mei Sun sp. nov. is similar to S. hongkongensis, S. nivea and S. sinensis, but can be differentiated on the basis of its allogamous mode of reproduction from S. hongkongensis and S. nivea which are both autogamous. It can also be easily separated from S. nivea by its pubescent body. Other morphological distinctions separating this new species from S. hongkongensis, S. nivea and allogamous S. sinensis include: floral bract longer or of the same length as the ovary, petals with blunt apex, labellum width around hypochile is same as the width of epichile, epichile widely flabellate or semi-tunicate, column length equal to or more than 1.5 mm, clavate operculum attached to the column on the broader part by an arm-like extension emerging from the upper part of column and a well-developed rostellum separating the stigma from the pollinarium.
Terrestrial herbs with perennating rhizome. Plants c. 16–30 cm tall. Rhizome about 3mm in diameter. Stem erect, leaf clustered towards the base. Leaves 2 to 5 per plant, broadly linear or linear-lanceolate, 4.0–6.0 cm long, ca. 1.5cm wide, 3-veined with depression on upper surface and elevated lining underneath, spreading from the base of the stem. Inflorescence tall, up to 30 cm long, terete, pubescent, covered with glandular hairs, with 1–3 sterile bracts sheathing the peduncle, flowers spirally arranged, clustered towards the upper one-fourth of the peduncle with flowers opening from the base. Flowers widely open 0.22 × 0.26 cm wide, 0.43 cm long, pale white to pale butter-white, pubescent with glandular hairs. Bracts green, equal to or longer than the combined length of pedicel and ovary, ovate-lanceolate, 0.40–0.50 cm long, ca. 0.17 cm wide, acuminate, hairy on the outer surface, sheathing the base of flower, margin white. Dorsal sepal white, hairy towards the base, elongated-triangular, 0.35–0.40 cm long, ca. 0.10 cm wide, obtuse. Lateral sepals white, pubescent towards the base, obliquely elliptic, 0.37–0.40 cm long, 0.10 cm wide, obtuse. Petals white, pubescent towards the base, obliquely elliptic, ca. 0.37 cm long, ca. 0.07 cm wide towards the base, 0.09 cm wide towards apex, apex blunt. Labellum white, distinctly divided into hypochile and epichile with a constriction in the middle, hairy on the outer surface, ca. 0.50 cm long; hypochile concave, ca. 0.30 cm long, 0.33–0.34 cm wide, attached at the base of short foot below the column, saccate, sac 0.05 cm deep, with one semi-globular gland on each side (0.05 cm wide, 0.04 cm high), margin entire and raised upwards till the constriction; epichile semi-tunicate, flabellate, ca. 0.20 cm long, ca. 0.30 cm wide, margin undulate, slightly dentate with some papillose hairs on the front semi-tunicate part. Column green-white, obconical, quadrangular transversely quandrangular, 0.25 cm long, 0.05 cm at the base, 0.07 cm wide towards the apex, with a short foot at the base, 0.06 cm long, stigma at the apex on the lower side, green in colour, shiny, filled with viscid liquid, trapezoid shaped, broad towards base (0.08 cm), narrower towards apex (0.06 cm), 0.06 cm long. Rostellum well developed with two semi-transparent, clavate, rostellar arms projecting in the front above stigma, 0.06 cm long. Pollinarium yellow, ovate with a deep cleft, 0.22 cm long, 0.09 cm wide, narrower end at the apex while the lobes inside covered with operculum, with a ligulate viscidium at the narrower end, 0.1 cm long. Operculum yellow-brown coloured, partly embedded on the upper part of column, not free, convex, ca. 0.10 cm long, 0.06 cm wide. Ovary sessile or with inconspicuous pedicel, densely haired, fusiform, 0.20–0.25 cm long, 0.11–0.13 cm wide. Fruits obliquely clavate, ca. 0.30 cm long, 0.12 cm wide, densely pubescent with glandular hairs.
Flowering: March–June. Fruiting: March–July.
Marshy areas near mountain streams or on bunds of paddy fields (Fig.
The specific name refers to the mighty Himalayan mountain range which is an important geographical feature in Asia. The samples collected for this study were not from the Himalayas. However, based on herbarium records and communication with other researchers, it is believed that this species is widespread in the lower altitudes of Himalayas. The evolutionary origin of this species and other Asian Spiranthes are to be further elucidated.
India (Karnataka, Manipur & Tamil Nadu) & China (Yunnan and most likely Hainan (see taxonomic notes for details)).
Based on DNA analysis, the occurrence of Spiranthes himalayensis can be confirmed in India and China. This species is likely to be present in a much wider geographic range where it has long been misidentified (see taxonomic notes). It was not possible to assess the specimens which might have been misidentified as S. sinensis or S. spiralis across its broad distributional range. It is emphasised that the type specimen was collected in an agricultural field and other specimens were found on roadsides along mountain slopes above 1000 m in its wide distributional range. Therefore it is speculated that this species might be of least concern for conservation. However large-scale habitat loss and fragmentation of habitats in Asia might pose a threat to this species. Since a thorough assessment has not been undertaken, the conservation status of Not Evaluated (NE) has been assigned to this species as per IUCN Red List categories and criteria (2017).
INDIA. Manipur: Ukrul district, Imphal-Jessami Road, found on paddy fields on the way to Ukhrul town, 1200 m, 1 May 2016, S. Surveswaran 1HJCB 1001 (M1-DNA specimen) (JCB); Karnataka: Chickmagalur district, near Kemmankundi, 1400 m, 14 June 2015, S. Surveswaran 4 (HJCB 0442) (C1-DNA specimen) (JCB!); Tamil Nadu: Coimbatore, near Konalar anti-poaching protection camp, Grass Hills, Valparai Range, Anaimalai Tiger Reserve, 1200 m, 13 March 2012, K. Ravikumar & A.C. Tangavelou FRLH-121312 (FRLH!). CHINA. Yunnan Province: Malipo County, Wenshan, near Xiajinchang village, 1400 m, 20 May 2016, S. Surveswaran S52.
Spiranthes himalayensis Survesw., Kumar & Mei Sun, sp. nov. A Complete plant B Inflorescence C Floral bract D Dorsal sepal E Lateral sepal F Petal G Ovary with column and labellum H Close-up showing the glandular hairs on flower and ovary I Side view of labellum J Top view of labellum K Side view of ovary with column L Front view of ovary and column M Front view of pollinarium N Side view of pollinarium. Note: The pinkish/bluish hue on petals of S. himalayensis is due to the black background in the plates while the flowers appear fully white in natural light.
Comparison of morphological characters of allied species. A Spiranthes himalayensis: 1 Close-up of inflorescence 2 A flower 3 Floral bract 4 Dorsal sepal 5 Lateral sepal 6 Petal 7 Ovary with column and labellum 8 Labellum (side view) 9 Labellum (top view) 10 Close-up showing glandular hairs on labellum and ovary 11 Ovary with column (side view) 12 Ovary with column (ventral view) B S. sinensis: 1 Close-up of inflorescence 2 A flower 3 Floral bract 4 Dorsal sepal 5 Lateral sepal 6 Petal 7 Ovary with column and labellum 8 Labellum (side view) 9 Labellum (top view) 10 Ovary with column (side view) 11 Ovary with column (ventral view) C S. hongkongensis: 1 Close-up of inflorescence 2 A flower 3 Floral bract 4 Dorsal sepal 5 Lateral sepal 6 Petal 7 Ovary with column and labellum; 8. Labellum (side view) 9 Labellum (top view) 10 Close-up showing glandular hairs on labellum and ovary 11 Ovary with column (side view) 12 Ovary with column (ventral view) D S. nivea: 1. Close-up of inflorescence; 2. A flower 3 Floral bract 4 Dorsal sepal 5 Lateral sepal 6 Petal 7 Ovary with column and labellum 8 Labellum (side view) 9 Labellum (top view) 10 Close-up showing glandular hairs on labellum and ovary 11 Ovary with column (side view) 12 Ovary with column (ventral view). Note: The pinkish/bluish hue on petals of S. himalayensis, S. nivea and S. hongkongensis is due to the black background in the plates while the flowers appear fully white in natural light.
Hairy Spiranthes have been reported very often from India, sometimes under the name of S. sinensis (
Based on DNA studies (Fig.
Comparison of morphological characters of Spiranthes himalayensis Survesw., Kumar & Mei Sun, sp. nov., S. sinensis, S. hongkongensis and S. nivea.
Character | Spiranthes himalayensis | Spiranthes sinensis | Spiranthes hongkongensis | Spiranthes nivea |
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Flowering time | March to June | April to June (in Hong Kong), August to September (in India) | March to early June | April to June |
Inflorescence | Pubescent with glandular hairs | Pubescent or sometimes glabrous | Pubescent with glandular hairs | Glabrous, but with microscopic non-glandular papillose hairs |
Flower | White, pale white, widely open, 0.4–0.5 × 0.15 cm wide, ca. 0.43 cm long | Pink, or purple, but occasionally white, widely open, 0.19 × 0.22 cm wide, ca. 0.45 cm long | White, petals and sepals rarely pink tinged, labellum white, widely open, 0.10, 0.12 cm wide, ca. 0.38 cm long | White, tubular on lower 2/3rd, open towards the tip, 0.09 × 0.09 cm wide, ca. 0.41 cm long |
Bract | Equal to or longer than ovary, 0.4–0.5 cm long, ca. 0.17 cm wide | Equal to or longer than ovary, 0.36 cm long, 0.14 cm wide | Equal to or shorter than ovary, ca. 0.37 cm long, 0.19 cm wide | Much longer than ovary arching over the flower, 0.49 cm long, 0.16 cm wide |
Petal | Apex blunt | Apex rounded | Apex rounded | Apex blunt |
Labellum | Labellum white, pubescent on the outer surface, distinctly divided into hypochile and epichile with a constriction in the middle, ca. 0. cm long; hypochile ovate, concave or saccate, ca. 0.30 cm long, 0.33–0.34 cm wide, sac 0.05 cm deep, with a pair of semi-globular gland at the base (0.05 cm wide, 0.04 cm high), margin entire and raised upwards till the constriction, two broad pale green patch at the constriction; epichile semi-tunicate, flabellate, ca. 0.20 cm long, ca. 0.30 cm wide, margin undulate, slightly dentate with some papillose hairs on the front semi-tunicate part | Labellum pink or white, glabrous, not distinct into epichile and hypochile due to lack of constriction, rather a semi-cylindrical basal portion with tunicate or flabellate frontal portion, 0.46 cm long; basal portion 0.15 cm wide, 0.23 cm long, saccate, sac 0.03 cm deep, margin raised with a pair of semi-globular glands at the base (0.05 cm wide, 0.05 cm high), margin smooth towards base, undulate from almost middle of the basal portion to the whole length of frontal portion; frontal portion semi-tunicate or flabellate, 0.13cm long, 0.16 cm wide at base, 0.35 cm wide towards the apex, margin undulate, slightly dentate | Labellum white with rare pinkish tinge, distinctly divided into hypochile and epichile with a constriction in the middle, ca. 0.58 cm long; hypochile ovate, slightly concave or saccate, 0.26 cm long, 0.32 cm wide, 0.06 cm deep, with a pair of trapezoidal shaped gland at the base (0.09 cm wide, 0.07 cm high), margin entire and raised upwards till the constriction; no colour patch at the constriction; epichile semi-tunicate, flabellate, ca. 0.26 cm long, ca. 0.26 cm wide, margin undulate, slightly dentate, glabrous |
Labellum white, glabrous, not distinct into epichile and hypochile due to lack of constriction, rather a semi-conical basal portion with semi-cylindric frontal portion, 0.43cm long; basal portion 0.24 cm wide towards base, 0.14 cm wide towards upper part, 0.24 cm long, saccate, sac 0.03 cm deep, margin raised with a pair of semi- globose glands at the base (0.04 cm wide, 0.04 cm high), margin smooth till the base of frontal part of labellum; frontal portion not widely spreading, margin convolute, 0.19 cm long, 0.16 cm wide at base, 0.14 cm wide towards the apex, margin undulate towards base and slightly dentate towards apex |
Labellum apex | Recurved, > 270 degrees | Strongly recurved, almost 360 degrees | Recurved by < 270 degrees | Recurved by < 270 degrees |
Column | Column, obconical, 0.25 cm long, 0.05 cm at the base, 0.07 cm wide towards the apex; foot 0.06 cm long; stigma trapezoid shaped, broad towards base (0.08 cm), narrower towards apex (0.06 cm), 0.06 cm long. | Column conical, 0.23 cm long, 0.08 cm wide at the base, 0.10 cm wide at the apex; foot 0.05 cm long; stigma almost semicircular in shape, 0.09 cm wide | Column, obconical, 0.21 cm long, 0.07 cm at the base, 0.09 cm wide towards the apex; foot 0.05 cm long; stigma crescent or semicircular shaped, 0.08 cm wide | Column obconical. 0.12 cm long, 0.04 cm wide at base, 0.05 cm wide towards apex; foot 0.04 cm long; stigma semicircular in shape, 0.05 cm wide |
Operculum attachment on column | An inconspicuously separating arm on the top of column attached to the front broader part of operculum | An extension from the upper part of column protruding out and attached to the top of operculum | Broader front of operculum embedded in the column (no extension projecting from column on to operculum) | Almost half of the broader part of operculum embedded on to the top of the column (no extension projecting from column on to operculum) |
Rostellum | Well developed with two semi-transparent, clavate, rostellar arms projecting in the front above stigma, 0.06 cm long. | Well developed with two semi-transparent, clavate, rostellar arms projecting in the front above stigma, 0.05 cm long | Not visible or absent | Not visible or absent |
Pollination | Allogamous | Allogamous | Autogamous (due to lack of rostellum, pollinia falls on the stigma on its own) | Autogamous (due to lack of rostellum, pollinia falls on the stigma on its own) |
Based on preliminary chromosome counts, Spiranthes himalayensis and S. nivea both have a diploid chromosome number of about 30, similar to S. sinensis. It has been confirmed that S. hongkongensis is an allotetraploid (4× = 60), with S. sinensis as its maternal progenitor (
We thank, Joy Horam for field assistance, Professor Suhua Shi for help with Yunnan samples and Dr. K. Ravikumar (FRLHT, India) for providing some information on new occurrences. This work was supported by a HKRGC grant (GRF-17101616) and a CRCG grant (201511159168) to Mei Sun.