Deinostigma
Deinostigma poilanei W.T.Wang & Z.Y.Li, type species, flower and flower buds, note white sepals
Cult. Roy. Bot. Gard. Edinburgh. Photo: Nate@AvisRapax
Deinostigma poilanei (Pellegr.) W.T.Wang & Z.Y.Li (A–E) (type species) and D. tamianum (B.L.Burtt) D.J.Middleton & H.J.Atkins (F–J). A. Habit. B. Flower in side view. C. Flower front view. D. Immature fruit. E. Mature fruit. F. Habit. G. Flower in side view. H. Flower in front view. I. Immature fruit. J. Mature fruit. (Photos: A, B, C, F–J: M. Möller; D, E: Sadie Barber)
From Möller et al. (2016), Fig. 6.
Deinostigma cicatricosum (W.T.Wang) D.J.Middleton & Mich.Möller (A–D) and D. cyrtocarpum (D.Fang & L.Zeng) Mich.Möller & H.J.Atkins (E–H). A. Habit and mature fruits. B. Flower cut open. C. Flower top view. D. Flower front view. E. Habit. F. Mature fruits. G. Flowering branch. H. Flowers front view. (Photos: A, B, E, F: M. Möller; C, D, G, H: Yi-Gang Wei).
From Möller et al. (2016), Fig. 5.
Deinostigma fasciculatum W.H.Chen & Y.M.Shui, sp. nov. A habit B mature fruits C frontal view of flower D leaf abaxial side E top and back view of flowers F top view of opened corolla showing the interior surface of corolla tube, stamens and staminodes G pistil and calyx, arrow showing the calyx H ovary, calyx and bract. (b = bract, c = calyx, d = disc).
From Shui et al. (2020), Fig. 2.
Deinostigma tamianum (B.L.Burtt) D.J.Middleton & H.J.Atkins; flowering plant;
Photo: Michael Wolf, Wikipedia. Licence: CC BY-SA 3.0
Deinostigma
Full name and orig. publication: Deinostigma W.T.Wang & Z.Y.Li, Acta Phytotax. Sin. 30 (4): 356 (1992).
Etymology: From the Greek δεινος, deinos = excessive, exceeding, tremendous, and στιγμα, stigma = stigma, referring to the two rather large and equal stigma lobes.
Synonyms: -
Infrafamilial position: Didymocarpoideae-Trichosporeae-Didymocarpinae (Weber et al. 2013).
Description (from Möller et al. 2016: 155): Perennial herbs, caulescent with distinct or short stem. Leaves simple, alternate, sometimes congested into a rosette, petiolate; blade slightly peltate or not, margin crenate or dentate, secondary veins pinnate. Inflorescences axillary, cymose; pedicels with hooked hairs. Flowers with the pedicel inserted at an angle and off-centre on the receptacle. Calyx lobes divided to base, elliptic, those on ventral side slightly longer and wider. Corolla white, purple, blue or combinations thereof, infundibuliform, lower lip 3-lobed, upper lip 2-lobed, lobe apices rounded. Fertile stamens 2, filaments slightly curved, anthers adnate face to face, hairy or with glands, staminodes 3 but with central staminode sometimes obscure. Nectary 5-crenate or apparently lacking. Ovary fusiform, bilocular throughout or at least near base, then unilocular from middle to apex; stigma of only lower lip developing, broad, flat and weakly 2-lobed. Fruit straight to strongly falcate, oblique in relation to the pedicel, dehiscing loculicidally; many-seeded, seeds unappendaged.
Chromosome number: 2n = 32 (D. poilanei, D. cicatricosa), 2n = ca. 30 (D. cyrtocarpus (Möller et al. 2016).
Species number: 8.
Species names: Deinostigma cicatricosum (W.T.Wang) D.J.Middleton & Mich.Möller, D. cycnostylum (B.L.Burtt) D.J.Middleton & H.J.Atkins, D. cyrtocarpum (D.Fang & L.Zeng) Mich.Möller & H.J.Atkins, D. eberhardtii (Pellegr.) D.J.Middleton & H.J.Atkins, D. fasciculatum W.H.Chen & Y.M.Shui, D. minutihamatum (D.Wood) D.J.Middleton & H.J.Atkins, D. poilanei (Pellegr.) W.T.Wang & Z.Y.Li, D. tamianum (B.L.Burtt) D.J.Middleton & H.J.Atkins.
Type species: Deinostigma poilanei (Pellegr.) W.T.Wang & Z.Y.Li (= Hemiboea polanei Pellegr.).
Distribution: Southern China and Vietnam, possibly also Laos.
Notes:
(1) Deinostigma was originally described as monotypic with D. poilanei (originally referred to Hemiboea). This remained so until Möller et al. (2016), based on molecular-systematic results, added 6 species by transfer from Primulina (formerly Chirita sect. Gibbosaccus). Recently, a new species (D. fasciculatum W.H.Chen & Y.M.Shui, was described (Shui et al. 2020), so that the species number presently holds at 8.
(2) The systematic-phylogenetic position is rather with Metapetrocosmea than with Primulina.
(3) Characteristic morphological features include: Plants perennial, apparently deciduous, with the dropping leaves leaving distinct leaf scars on the stem; leaf arrangement alternate; presence of hooked hairs on many plant parts (especially pedicels); corolla infundibuliform, white, blue or variations on purple; fertile stamens 2; internal structure of the ovary ranging from unilocular to bilocular (with the lower carpel sterile), fruit a rather short, plagiocarpic, upcurving capsule opening mainly on the dorsal side.
(4) Pollination is probably by bees (observations are lacking).
Tax. details, cytology, and bibliography: Gesneriaceae Resource Centre (GRC). Royal Botanic Garden Edinburgh.
Page content and update responsibility/contact: Anton Weber.
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