Diabelia Landrein, 2010

Landrein, Sven, 2010, Diabelia, a new genus of tribe Linnaeeae subtribe Linnaeinae (Caprifoliaceae), Phytotaxa 3, pp. 34-38 : 35-37

Diabelia Landrein , gen. nov.

Basionym:— Linnaea subgenus Abelia sect. Bilaciniatae ser. Serratae Graebner (1901: 133) .

Synonym:— Abelia sect. Serratae (Graebner) T.Kim & B.Sun , ined. (1998, unpublished thesis).

Type species:— Diabelia serrata (Siebold & Zucc.) Landrein = Abelia serrata Siebold & Zuccarini (1835: 76 , t. 34.)

Original diagnosis ( Graebner 1901): Pedunculi terminalis in apice ramulorum brevium lateralium vel terminalium, 2- rarius 3- vel 4-flori. Flores sessiles, basi bracteis minutis instructi.

Deciduous shrubs. Winter buds exposed, with several pairs of scales. Branches terete, without grooves. Wood ring porous and vessels with simple perforation. Leaves opposite, shortly petiolate with an interpetiolar line. Leaf margin entire to serrate, often undulate. Flowers terminal and paired at end of short shoots, the flowers opening simultaneously, sometimes 1–3(–8) due to supernumerary flowers axillary to the bracts (more often so on repeatedly-blooming long shoots); paired flowers with six bracts, these small and not accrescent, forming an ‘epicalyx’ just below the ovary. Sepals 2–5, spreading, narrowly oblong, elliptic persistent and ± accrescent in fruit. Corolla 5-lobed, bilabiate, white, yellow, pink, or red; tube ventrally gibbous and containing a nectary of dense glandular hairs (nectaria trichomalia); nectary sometimes clavate and free. Stamens didynamous, adnate to the corolla tube, included or exserted; anthers introrse. Pollen echinulate without endocingulum, 3–4 porate. Ovary narrowly oblong, 3-locular, two locules with two series of sterile ovules, one locule with a single fertile ovule; style 1, filiform; stigma capitate, white and papillose. (see Fig. 1 . for floral diagram). Fruit an oblong, leathery achene, crowned with persistent sepals. Seed subterete, testa membranous; endosperm fleshy. Figure 2.

Vernacular names:—Tsukubane utsugi (= ‘shuttle-cock deutzia’) in Japanese; Twin abelia in English.

The genus consists of three species in Japan ( Hara 1983). Two of these species ( D. serrata and D. spathulata ) have recently been discovered in Zhejiang, China ( Zhou et al. 2006).

Figures

FIGURE 1. Floral diagram and formula of a Linnaeeae flower. Drawn with Microsoft Word 97-2002 according to Prenner et al. (2010). K(2–5)* [C(5)↓ A1r:4↓] Ĝ(1:2r)↓V×1:∞r