Notothylas Irregularis (Notothyladaceae, Anthocerotophyta), a New Species of Hornwort from Northern Thailand

Acta Botanica Hungarica 56(3–4), pp. 269–274, 2014 DOI: 10.1556/ABot.56.2014.3–4.3

NOTOTHYLAS IRREGULARIS (NOTOTHYLADACEAE, ANTHOCEROTOPHYTA), A NEW SPECIES OF HORNWORT FROM NORTHERN THAILAND

S. Chantanaorrapint Department of Biology, Faculty of Science, Prince of Songkla University Hat Yai, Songkhla 90112, Thailand; E-mail: [email protected]

(Received 24 February, 2014; Accepted 15 July, 2014)

Notothylas irregularis Chantanaorr. is described and illustrated from Doi Chiang Dao Wild- life Sanctuary, Chiang Dao District, Chiang Mai Province, northern Thailand. It is similar to Notothylas yunnanensis T. Peng et R. L. Zhu, but differs in its capsules with a line of incrassate cells.

Key words: hornworts, new species, Nothothyladaceae, Notothylas irregularis, Thailand

INTRODUCTION

The genus Notothylas Sullivant ex A. Gray (1846: 74) comprises about 22 species worldwide and is distributed in mostly tropical to temperate regions. The highest species diversity of the genus is in the Indian subcontinent (Duff et al. 2007, Frey and Stech 2009, Peng and Zhu 2014, Singh 2002, Villarreal et al. 2010). This genus is well characterised by the small and solid thallus, anth- eridial chambers with usually 2–4(–6) antheridia; capsules very short, laying horizontally in thallus, mostly enclosed within the involucre, and capsules without stomata. The first report of Notothylas in Thailand was published by Hasegawa (1979), who described a new species, N. depressispora J. Hasegawa (1979: 26), based on a collection made by N. Kitagawa from Chiangrai Province. Chan- tanaorrapint (2007) reported three additional species to the Thai flora including: N. javanica (Sande Lacoste 1856: 94) Gottsche (1858: 20), N. levieri Schiffner ex Stephani (1917: 1021) and N. orbicularis (Schweinitz 1821: 23) Sullivant ex A. Gray (1846: 75). Recently, Lai et al. (2008) published an updated checklist

Unauthenticated | Downloaded 09/25/21 06:25 AM UTC 270 CHANTANAORRAPINT, S. of liverworts and hornworts of Thailand and confirmed already mentioned four species of Notothylas in Thailand. However, there have not been intensive studies of the genus in Thailand so far. While revising the division Anthocero- tophyta for the bryophyte flora of Thailand, a new species of Notothylas was found. It has a unique combination of characters that does not match any ex- isting described species, hence is described here as a new species.

MATERIALS AND METHODS

The new species was described and illustrated based on the herbarium specimens from BKF, EGR, G and PSU. Morphological and anatomical characters were studied by stereo and upright microscope. The distinctive characters of the species were illustrated with the aid of a drawing tube Olym- pus. Fresh sporangia collected in the field and preserved in 70% ethyl alcohol were dehydrated in 90% and absolute ethyl alcohol, respectively, before criti- cal point drying (CPD). Mature spores were dissected from sporangia and mounted on double-stick cellophane adhesive tape affixed on stubs. Spores were then plated with a thin layer of gold and examined with a FEI Quanta 400 scanning electron microscope.

TAXONOMIC TREATMENT

Notothylas irregularis Chantanaorr., spec. nov. (Figs 1, 2)

Type: Thailand, Chiang Mai Province, Chiang Dao District, Doi Chang Dao Wildlife Sanc- tuary, 1,633 m, 19° 23’ 35.70” N, 98° 53’ 11.26” E, 9 August 2012. Coll.: S. Chantanaorrapint and J. Inuthai 1615 (holotype: PSU!; isotypes: BKF!, EGR, G!).

Diagnosis: Notothylas yunnanensis T. Peng et R. L. Zhu valde affinis, sed differt capsulis cum linea cellulis incrassatis. Plants yellowish green to dark green in fresh material, forming orbicular or fasciculate rosettes, 5–15 mm in diameter, densely overlapped, prostrate or closely adhering to the substratum, irregularly branched, without tubers. Thalli solid without schizogenous cavities, ecostate, flattened dorsally and convex on the ventral side in transverse section, 5–7 cells thick in the middle, with a smooth dorsal surface; margin deeply lobed, lobes narrow, apex trun- cate or shortly lacerate; dorsal epidermal cells rectangular, quadrate or rhom- boidal-hexagonal, 50–90 × 30–60 μm, with a solitary chloroplast; pyrenoid present. Nostoc colonies irregularly disposed on the ventral side of thallus, appearing as dark dots. Rhizoids hyaline or pale brown along ventral surface, inner wall smooth or tuberculate.

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Fig. 1. Notothylas irregularis Chantanaorr. A–B = thallus with sporophytes; C = transverse section of thallus; D = dorsal epidermal cells of thallus; E = capsule with dehiscence line; F = epi dermal cells of the capsule showing the special row of thick-walled and reddish brown cells; G = proximal view of spore; H = distal view of spore. All from the holotype (PSU; S. Chantanaorrapint and J. Inuthai 1615)

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Fig. 2. Notothylas irregularis Chantanaorr. A = thalli with sporophytes; B = epidermal cells of the capsule showing the special row of thick-walled and reddish brown cells; C–F. SEMs of spores: C = proximal view of spore; D = distal view of spore; E = high magnification of the proximal face showing vermiculate surface with a small hollow in centre; F = high magnification of the distal face showing densely vermiculate surface. All from the holotype (PSU; S. Chantanaorrapint and J. Inuthai 1615)

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Monoicous. Androecia scattered, antheridia subglobose, 2–3 per cavity. Involucres usually solitary, spreading horizontally or slightly ascending, cylindrical to conical, rather thick, longitudinally plicate or lamellate, but not lobulate erect. Capsules cylindrical or banana-shaped, 1.2–2.2 mm long, 0.2– 0.5 mm in diameter, completely enclosed by the involucre, capsule dehiscing longitudinally along suture lines, with 2–3 rows of thick-walled and reddish brown cells; capsule wall 2–3(–4) cell layers thick; epidermal cells subquadrate to sub-rectangular to rectangular, 45–90 × 20–45 μm; moderately thick- walled, irregularly nodulose thickening; columella well-developed. Spores yellowish to pale brown, unicellular, tetrahedral trilete, rounded-triangular in polar view, equatorial view fan-shaped, equatorial diameter 30–35 μm; proximal portion subpyramidal, vermiculate, each proximal surface with a central depression; distal surface more densely vermiculate than proximal surface, with a slightly dome-like region at the centre. Pseudoelaters absent (perhaps disintegrated in the late stage of development). Etymology: The epithet “irregularis” refers to the irregularly nodulose thickening walled of epidermal cells of capsule. Distribution: Notothylas irregularis is at present known only from the type locality, but it might have a wider distribution at least in other parts of northern Thailand. Habitat: The type specimen was found growing with other hornworts, such as Anthoceros subtilis Stephani (1916: 1003), Notothylas orbicularis (Schwein.) Sull. and Phaeoceros perpusillus S. Chantanaorrapint (2009: 30) on disturbed soil along walking trail ca 1,600–1,900 m in rainy season. Additional specimen examined: Thailand, Chiang Mai Province, Chiang Dao District, Doi Chang Dao Wildlife Sanctuary, 1,884 m, 19° 23’ 33.68” N, 98° 52’ 23.92” E, 8 August 2012. Coll.: S. Chantanaorrapint and J. Inuthai 1605 (paratype: PSU!). Notes: Notothylas irregularis is closely related to N. yunannensis T. Peng et R. L. Zhu, an endemic species of Yunnan, China (Peng and Zhu 2014), which also has vermiculate spores with a small hollow on each proximal facet, and the epidermal cells of the capsule are subquadrate to rectangular and irregularly arranged. But this new species is different from N. yunannensis by the presence of the dehiscence line of the capsule marked by 2–3 rows of thick- walled, reddish brown cells (the capsule of Notothylas yunnanensis is not val- vate, without any special row of thick walled cells (Peng and Zhu 2014)) and by the more densely vermiculate proximal face of spores (Figs 2C, D). The new species also resembles Notothylas himalayensis Udar et D. K. Singh (1981: 451), in having the special dehiscence line of the capsule, consist- ing of 2–3 rows of thick-walled and reddish brown cells, and the other epidermal cells of capsule are moderately thick-walled with irregularly nodulose thickening. However, the former differs from the latter in having pseudoelat-

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Acknowledgements – The author would like to thank late Prof. Dr Jan-Peter Frahm for checking the Latin diagnosis and Assoc. Prof. Dr Kitichate Sridith for his valuable comments on the first draft of the manuscript. Finally, thanks also go to the director and staffs of G, HSNU and L for making specimens including types available for study through loans or visits. This research was supported by Faculty of Science, Prince of Songkla University, Songkhla, Thailand.

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