Polystachya danielana G.W.Hu, W.C.Huang & Q.F.Wang, 2019

Tian, Jing, Huang, Wei-Chang, Mbuni, Yuvenalis Morara, Kamau, Peris, Mwachala, Geoffrey, Malombe, Itambo, Hu, Guang-Wan & Wang, Qing-Feng, 2019, Polystachya danielana (Orchidaceae: Polystachyinae), a new species from Kenya, Phytotaxa 405 (4), pp. 195-202 : 197

Polystachya danielana G.W.Hu, W.C.Huang & Q.F.Wang , sp. nov. ( Figs. 2 , 3 )

Type :— KENYA. Elgeyo-Marakwet County: Kipkunur , Kapsowar town , Cherangani Hill, 00° 58 ′ 49.48 ″ N, 35° 30 ′ 31.25 ″ E, 2670 m, 2 May 2018, Sino-Africa Joint Investigation Team ( SAJIT)-007105 (holotype HIB!; isotype EA!, HIB!) .

Epiphytic herbs, ca. 13 cm tall. Roots numerous, up to 13 cm long, ca. 3 mm thick. Pseudobulbs (stems) narrowly cylindrical or rarely swollen in the lower middle part, 2.0–3.0 × 0.6 cm, mostly arising from the nodes near the base of the previous growth, few from the middle or upper nodes, with 3–5 sheaths. Leaves 2, narrowly oblong or narrowly ovate-lanceolate, 2–8 × 1–2 cm, base gradually tapered into a petiole, apex obtuse or unequally shallowly bilobed. Inflorescences terminal, 2–5 cm long, with 4–7 flowers, peduncle tomentose, unbranched. Flowers purple to yellowgreen; bracts oblong, 4 × 3 mm, apex emarginate with a caudate tip; pedicel and ovary 1.0– 1.5 cm long, purple, tomentose. Dorsal sepals subovate, 5.0–7.0 × 3.0– 4.5 mm, apex acuminate; lateral sepals obliquely ovate-orbicular, apex recurved, 7–9 × 4–6 mm, abaxially tomentose, borne on a ca. 6 mm long column foot and forming a sac; petals oblong, 5.0–6.0 × 1.5–2.0 mm, apex blunt; lip 8 × 5 mm, recurved, hypochile hairy, mesochile hairy, epichile trilobed, lateral lobes incurved, oval, midlobe orbicular, 3.5 × 3.5 mm, margin undulate and irregularly erose, apex blunt; column 2.5 mm long. Capsule trigonal-ellipsoid, 2.7 cm long.

Distribution and ecology:— Currently known only from the type locality, as an epiphytic herb growing in moss on lower parts of trunks of Podocarpus milanjianus Rendle (1894: 61) .

Phenology:— Flowering in May.

Etymology:— Named in memory of Daniel Odhiambo Miyawa, a botanist from the National Museums of Kenya, who spent his brief life studying Kenyan orchids.

Additional s pecimens examined:— Polystachya spatella : KENYA. Nandi County: North Nandi Forest, Tabolwa , 24 April 2018, SAJIT-007027 ( EA, HIB). Elgeyo-Marakwet County: Kapsowar, Kipkunur, 2 May 2018, SAJIT-007103 ( EA, HIB) ; Kararia , 4 May 2018, SAJIT-007128 ( EA, HIB). DEMOCRATIC REPUBLIC OF THE CONGO. 12 April 1934, Witte 1501 ( BR) ; May 1894, Scott Elliot 7796 ( K). RWANDA. 1 March 1992, Delepierre 135 ( BR). Polystachya kermesina : RWANDA. 27 December 1971, Bouxin 1273 ( BR). DEMOCRATIC REPUBLIC OF THE CONGO. 1 November 1937, Lebrun 8719 ( BR) ; 1 July 1959, Léonard. 4774 ( YBI) ; 2 June 1959, Léonard 4475 ( YBI) ; 6 February 1958, Léonard 436 ( BR) ; 5 February 1958, Léonard 404 ( YBI) ; 26 January 1945, Germain 3477 ( YBI) ; 28 December 1930, Burtt 3084 ( BR) ; 1 November 1937, Lebrun 8719 ( BR) ; 7 August 1937, Louis 5271 ( YBI) .

Phylogenetic analysis:— Bayesian phylogenetic analyses of the combined ITS and psbD-trnT dataset shows that Polystachya danielana is a member of the clade of P. sect. Superpositae Kraenzlin (1926: 100) and is closely related to P. spatella and P. kermesina ( Fig. 1 ). This confirms its position in P. sect. Superpositae. The separate analyses did not exhibit any strong incongruence.

Figures

FIGURE 1. Bayesian tree of the combined dataset of nrITS and plastid psbD-trnT DNA sequences. Polystachya danielana is highlighted in red. Bayesian posterior probabilities are indicated for each node.

FIGURE 2. Polystachya danielana. A. Habit. B. Bracts. C. Flower, front view.D. Flower, lateral view. E. Dorsal sepal. F. Petal. G. Lateral sepal. H. Lip and column, front view. I. Lip and column, lateral view. J. Pollinium. K.Anther cap. L. Capsules. (Drawn by Jing Tian based on the holotype.)

FIGURE 3. Polystachya danielana. A. Habitat. B. Pseudobulbs. C. Inflorescence. D. Front view of flower. E. Dissection of a flower (including a bract). F. Column and stamen. G. Pollinium and anther cap. H. Capsule.