Phanera glauca subsp. tenuiflora var. murlenensis Ram.Kumar, Bandyop. et S.Sharma, 2014

Phanera glauca subsp. tenuiflora var. murlenensis Ram.Kumar, Bandyop. et S.Sharma View in CoL , var. nov.

( Figs. 1 View FIGURE 1 & 2 View FIGURE 2 )

Type:— INDIA. Mizoram: Murlen National Park, in the buffer region of the Park between Vapar to Ngur , ca. 1400 m, 11 April 2013, Ramesh Kumar & party 128363 (holotype CAL0000026092 !; isotype ASSAM! ).

Differs from Phanera glauca subsp. tenuiflora in having ovate leaves, retuse at apex or nearly so; inflorescence relatively small; hypanthium smaller than their respective pedicels. In subsp. tenuiflora leaves are ovate-orbicular, 1/9–1/5 bifid at apex, inflorescence relatively large; hypanthium longer than their respective pedicels.

Lianas with tendrils, ca. 10 m in height; hairs ferruginous when dry; tendrils flattened, pubescent. Leaves 3.7–7.7 × 3–7 cm, ovate, 9-nerved, retuse at apex or nearly so, truncate to subobtuse or shallowly cordate at base, glabrous above, pubescent beneath, particularly on the nerves, later glabrescent excepting the nerves; petioles 1.3–1.9 cm long, glabrescent. Stipules 5–9 mm long, linear-oblong. Racemes corymbose, axillary or terminal, pubescent. Flower buds 4–5 × 3–3.5 mm, ovoid, pubescent, particularly at apex. Hypanthium 8–9 mm long, tubular, striate in dried specimens, pubescent. Pedicels 2–2.4 cm long, slender, pubescent. Bracts 7–9 mm long, linear-oblong, pubescent; bracteoles 6–9 mm long, filiform, situated near the middle of pedicel. Flowers ca. 1.8 cm across. Calyx 2–3-lobed. Petals 7–9 × 4–8 mm, white, obovate to broadly obovate, obtuse at apex, veined, glabrous inside, glabrescent outside, particularly in the median zone; claw 2– 2.5 mm long, glabrescent. Fertile stamens 3; filaments 7–8 mm long, green, glabrous; anthers 2.5–3 mm long, reddish, ellipsoid. Reduced stamens 5, 1.5 – 2.5 mm long, with rudimentary anther at tip, swollen and connate at base; bases bright yellow. Staminodes 2, in between stamens. Gynophore ca. 3 mm long, sparsely pubescent to glabrous; ovary 0.6–1 cm long, greenish in the middle, reddish on the sutures, glabrous or glabrescent on the sutures particularly at base; style 3–4 mm long, reddish near the ovary, green upwards, glabrous; stigma ca. 1 mm across, green, obliquely peltate. Pod unknown.

Flowering:— April.

Distribution:— India (Mizoram).

Ecological status:— Two plants were seen in open forest on hill slope climbing on a tree.

Etymology:— The variety has been named after the Murlen National Park.

Chen et al. (2010) while working on the Chinese Bauhinia treated Bauhinia caterviflora Chen (1938: 129) , B. hupehana Craib (1914: 89) including var. grandis Craib (1914: 90) and B. pernervosa Chen (1938: 132) as synonyms of Bauhinia glauca var. tenuiflora (Watt ex Clarke) Larsen & Larsen (1973: 10) which by that time were considered as subspecies or varieties of Bauhinia glauca . We are accepting here only two subspecies namely, subsp. glauca and subsp. tenuiflora under P. glauca but at the same time do not agree with the taxonomic treatment of B. hupehana , including var. grandis . Chen et al. (2010) in the key characters of subsp. tenuiflora stated that the hypanthium in subsp. tenuiflora is 2.5–3 cm in length and longer than their respective pedicels. This is, however, not correct because we have examined the type of B. hupehana ( China, W. Hupeh, May 1907, E.H. Wilson 3373 K 000760713 image!) in which of the length of the hypanthium is 1.3–1.6 cm and they are shorter than the their respective pedicels, whereas in subsp. tenuiflora the hypanthium is longer than the respective pedicels. In the type of B. hupehana var. grandis ( China, Western Szechuan , Tung Valley , near Mt. Wa , 500 –1000 m, June 1908 & October 1908, E.H. Wilson 3372 K 000760712 image!) the length of the hypanthium is 1.5–1.8 cm. The leaves in both these collections are ca. 1/3 bifid at apex whereas in subsp. tenuiflora the leaves were stated by Chen et al. (2010) to be bifid only up to 1/5 at apex. Thus we feel that B. hupehana including var. grandis from Hupeh, Hunan and Szechuan most probably deserves to be accepted as a variety of subsp. tenuiflora . Both these type specimens though annotated by Supee S. Larsen as ‘ Bauhinia glauca (Wall ex Benth.) Benth. var. tenuiflora (Watt ex C.B. Clarke) K. & S. S. Larsen’ (1973: 10) in 1978, the identity was not clear to Supee S. Larsen at that time because in a later publication ( Larsen & Larsen 1984) they stated that B. hupehana is very close to subsp. tenuiflora and further studies on Chinese material are necessary before reaching a final decision on the taxonomic status of B. hupehana .

We are of the view that the distribution of subsp. glauca and subsp. tenuiflora is still not clearly known. If the morphological characters of B. hupehana would have been taken into account by Chen et al. (2010) then apart from the relative size of the inflorescence and the hairiness of the flower buds, the other characters included by them in the key to these subspecies do not hold good. Larsen & Larsen (1973) while dealing with subsp. glauca and subsp. tenuiflora in Thailand even stated that in Chanthaburi area intermediate forms between two subspecies seem to occur. One may feel that the local variations seem to be largely continuous when examining material across the wider range of distribution of the species from India, South China and through Myanmar, Thailand, Cambodia, Laos, Viet-nam and Malay Peninsula to Indonesia, but these infraspecific taxa do not pose much difficulty in identification in most of the cases when character combinations are taken into consideration together. We feel that at first the precise distribution of these taxa is to be elucidated followed by DNA sequence studies to resolve the intricate taxonomic problem.

In spite of this we have described this new variety because the morphological changes in var. murlensis does not seem to be due to range-distribution factor keeping in mind the localities of collections of subsp. tenuiflora made from N.E. India so far. The north-eastern part of India is, however, still under explored and this subspecies is likely to be collected from many more localities. The flowering collections (Coasts of Southern Burmah, S. Kurz s.n.; Shaik Mokim 145; Tavoy, Indraja rocks, Shaik Mokim 261; Browning Island, Victoria Point, CBSmales (?) 131; Amherst, Coll.? 611; Rangoon, Coll.? 40; Tenasserim, Helfer 1864) of subsp. glauca and those of (Maymyo plateau Ani Sakau, J.H. Lace 4849; Bhamo division, Palawugkathawng (?), G.E.S. Cubitt 285; Maymyo district, Govt. Botanical Garden, MgKan 576; Maymyo district, Bot. Garden, C.E. Parkinson 650) subsp. tenuiflora at CAL from Myanmar, a country adjacent to Mizoram in the east, represent typical morphological characters of subsp. glauca and subsp. tenuiflora var. tenuiflora .

Furthermore, we have preferred to describe var. murlensis as a new variety of subsp. tenuiflora because the collections come close to subsp. tenuiflora than to subsp. glauca considering the morphological characters and the typical subspecies has not yet been recorded ( Bandyopadhyay 2001) from India so far.

A comparative account of some morphological features between P. glauca subsp. glauca , P. glauca subsp. tenuiflora and P. glauca subsp. tenuiflora var. murlenensis are given in Table 1 View TABLE 1 .