Microchirita karaketii D.J.Middleton & Triboun, Thai Forest Bull. Bot.

Microchirita karaketii D.J.Middleton & Triboun, Thai Forest Bull. Bot. View in CoL 41: 17. 2013. Type: THAILAND, Chiang Mai, Chiang Dao district, Doi Chiang Dao Wildlife Sanctuary, Tam Pak Piang   GoogleMaps , 530 m, N 19°24.2’, E 98° 55.8’, 20.09.2008, D.J. Middleton, P. Karaket, P. Triboun, U. Kawatkul & R. Meeboonya 4526 (holo BKF; iso E [ E00629480 digital image!], P [ P00966764 digital image!], QBG). Fig. 1 View Fig

Lithophytic caulescent herbs, up to 60 cm tall. Stems succulent, glabrous, green with reddish base, internodes 4–7 cm long. Leaves opposite except for an enlarged single cotyledon; petioles 0.3–1 cm long, sparsely pubescent, green; blades ovate, 5–10 × 4–9 cm, base cordate, margins entire, ciliate, apex acuminate, sparse uniseriate hairs above and beneath; 6–16 pairs of secondary veins, steeply ascending, venation sunken above and raised beneath in the fresh material, flat in the herbarium specimens; tertiary venation reticulate, adaxial surface dark green, abaxial surface pale green. Inflorescence cristate, peduncles emerging to 10 mm long; bracts absent; pedicels 4–14 mm long, very sparsely hairy, pale green. Calyx bilabiate; lower lobes 3, free to base; upper lobes 2, unequal, irregularly fused, green; lobes narrowly lanceolate, 1–5 × 0.8–1.3 mm, margins entire, apex acuminate, sparsely hairy. Corolla white with a central yellow stripe in the throat and one lavender patch on each side of the yellow stripe, lobes white, tube narrow, curved downwards, 12.2–15.1 mm long above, 12–16 mm below, uniseriate hair outside, glabrous inside; lobes orbicular to elliptic, upper lobes, spreading, 3.2–4.4 × 3.3–5.2 mm; lateral lobes 3.7–4.4 × 4.2–5.2 mm; lower lobes 3.5–4.4 × 3.8–4.7 mm, apices rounded and sometimes obtuse. Stamens 2, filaments arising 4.4–6.5 mm above corolla base, straight, 2.3–3.5 long, c. 0.4 mm in diam., glabrous, creamy white; anthers 1.3–2 × 0.9–1.2 mm, sparse long indumentum at insertion, pale yellow, cohering face to face. Disk absent or a ventral half ring. Pistil 9.5–15 mm long; ovary 3.6–5 mm long, c. 1 mm in diam., papillose, pale green; style 6–7 mm long, pubescent, creamy white; stigma chiritoid, c. 1 mm long, creamy white. Undehisced mature fruit 4–5 cm long, c. 2 mm in diam., glabrous at the base with pubescence in the upper half, green. Seeds narrowly elliptic, c. 0.4 × 0.2 mm, brown.

Flowering & fruiting: Flowering is between July to October and fruiting is between September to November.

Habitat & floral ecology: It is found on moist, moss-covered rocks in tropical evergreen forests. Pollinator visitation study was carried out in September in three separate patches for two days by three independent observers (that is for a total of 24 observation hours, with each observation carried out from 8 AM to 12 PM resulting in 8 hours per observer). No floral visitors or pollinators were recorded during this time although abundant fruit sets were recorded in the population ( Fig. 1 View Fig ). The fruits in M. karaketii have pubescence in the upper half, which may be from the persistent pubescent

style. Similar partial pubescence in the fruit has also been noted in other Microchirita species from Thailand described by Puglisi and Middleton (2017). While we did not carry out detailed nectar analyses for M. karaketii we did note that nectar was absent in open and unbagged flowers that we checked (n=15). Further, although we did not test

42 A new record of Microchirita karaketii from India

the nature of the floral marks, we propose that corolla features such as the central yellow stripe in the corolla tube and one lavender patch on either side of this stripe may function as a nectar guide. In the absence of pollination biology studies in Microchirita , we recommend detailed ecological and reproductive biology studies to test the above hypothesis and to understand the evolution of floral traits within the genus.

Distribution: Northern Thailand, Myanmar, and now from India ( Fig. 2 View Fig ).

Specimens examined: INDIA, Meghalaya, East KhasiHillsdistrict, KynremFalls , N25°13’25.8348”, E 91°42’55.9584”, 928 m, 11.09.2017, S. B GoogleMaps . Rhuthuparna , S . Goray & R . Dandavate VG2017 ML5028 ; Ibid. , N 22°13’35.6556”, E 91°42’50.1516”, 928m, 11.09.2017, S. B GoogleMaps . Rhuthuparna , S . Goray & R . Dandavate VG2017 ML5029 ; Ibid. , N 25°13’38.0892”, E 91°42’59.9652’’, 928 m, 11.09.2017, S. B GoogleMaps . Rhuthuparna , S . Goray & R . Dandavate VG2017 ML5030 ; Ibid. , N 25°13’26.598”, E 91°42’58.3344”, 928 m, 11.09.2017, S. B GoogleMaps . Rhuthuparna , S . Goray & R . Dandavate VG2017 ML5031 ; Ibid. , N 25°13’24.5352”, E 91°43’0.9264”, 928 m, 11.09.2017, S. B GoogleMaps . Rhuthuparna , S . Goray & R . Dandavate VG2017 ML5032 ( BHPL) ; MYANMAR, Shan State, Taunggyi district, Pinglong township , N 19°58’31.54’’, E 96°14’8.9’’, 713 m, 14.09.2015, Y GoogleMaps . Baba. Kertsawang , C . Kilgour ,

C. Puglisi , M. Rodda , P. Srisanga , T. Shin , P. P. Hnin 103215 ( E [ E01007303 digital image]); Ibid. , N 19°58’26.6’’, E 96°40’13.1’’, 692 m, 15.09.2015 GoogleMaps , M. Rodda , K. Kertsawang , C. Kilgour , P. P. Hnin 103284 ( E [ E01007293 digital image]). THAILAND, Chiang Mai, Chiang Dao district , road to Wiang Haeng, N 19°38.9’, E 98°57.2’, 610 m, 21.09.2008 GoogleMaps , D. J. Middleton , P. Karaket , P. Triboun , U. Kawatkul & R. Meeboonya 4536 ( E [ E00629479 digital image]); Chiang Dao district, Kio Phawok border checkpoint, N 19°46’6’’, E 98°57’0’’, 750 m, 30.09.2009 GoogleMaps , D. J. Middleton , S. Lindsay & P. Suksathan 5017 ( E [ E00547441 digital image]) .

Conservation status: The species is currently known from eight locations across three countries: Thailand (6), Myanmar (1), and India (1). Some of these localities in Thailand are situated outside protected areas and are subjected to disturbance ( Puglisi & Middleton, 2017). In India, the species is documented from only one population from the state of Meghalaya, with approximately 300 mature individuals growing on moss-covered rocks spread across an almost 250 m-long continuous transect.

We calculated the Area of Occupancy (AOO) using GEOCAT (https://geocat.iucnredlist.org/; IUCN, 2022) where we included a total of eight locations from all the herbarium records that were available to us (K, E, CAL, SING, P). A 2 × 2 km grid scale was used as per the IUCN guidelines to calculate AOO. Based on this calculation, the AOO of the species is likely to be 32 km 2. Therefore, we propose that based on the criteria and conditions of B2ab(iii) of the IUCN Red List guidelines, the species should be considered Vulnerable (VU). The Indian population is located inside Thangkharang Park which is a protected area in the state of Meghalaya. However, this region remains under a constant threat of disturbance due to tourism and other possible developmental activities. Furthermore, we surveyed multiple other potential locations in Northeast India (except Tripura) and could not locate any other population. Based on this, we calculated the AOO to be 4 km 2 ( IUCN, 2022). Therefore, in India, the species should be considered to be Critically Endangered (CR) B2ab(iii).

Notes: Microchirita karaketii closely resembles M. bimaculata which is distributed in northern and northeastern Thailand, Laos, and Vietnam, and M. sahyadriensis , a species endemic to the Western Ghats of India. Microchirita karaketii differs from M. bimaculata in its white flower with a yellow stripe and two lavender patches placed ventrally inside the corolla tube (whereas M. bimaculata is bright yellow and has dark brown patches ventrally inside). Furthermore, Microchirita bimaculata can be distinguished from M. karaketii by the presence of scattered glandular hairs on the upper lobes and throat which is absent in M. karaketii . On the other hand, M. karaketii can be differentiated from M. sahyadriensis by the presence of sparse long indumentums at the insertion of the anther lobe, which is absent in M. sahyadriensis .

The Indian specimens examined here show geographical variation in their floral and fruit morphologies ( Table. 1). The Indian specimens have a relatively higher range of pedicel length, and larger corolla tubes compared to the original description ( Middleton & Triboun, 2013) from northern Thailand and the updated description provided in Puglisi and Middleton (2017). Additionally, the fruits of the Indian specimen are pubescent where the persistent style starts whereas the fruit is glabrous according to Middleton and Triboun (2013) and Puglisi and Middleton (2017). We noted this difference also in the specimen collected from the Kio Phawok border checkpoint (E00547441), and Wiang Haeng (E00629479), Chiang Dao district, Thailand, where the fruits are hairy where the persistent style starts.

Key tO SPeCieS OF MiCrOCHirita View in CoL in India

1. Fruits curved, 2–5 cm long .................................. 2

1. Fruits straight to slightly curved, 1.2–2 cm long ................................................................ M. hamosa View in CoL

2. Peduncles reduced or emerging or fused............ 3

2. Peduncles adnate to petiole.......... M. sahyadriensis View in CoL

3. Corolla white with marks inside the tube .......... 4

3. Corolla white........................................... M. cristata View in CoL

4. Corolla white with a yellow stripe inside the tube ............................................................... M. albiflora View in CoL

4. Corolla white with a yellow stripe inside the tube with two lavender patches on each side of the stripe .................................................... M. karaketii View in CoL