六道木属 liu dao mu shu

Abelia sect. Zabelia Rehder in Sargent, Pl. Wilson. 1: 124. 1911.

Shrubs, deciduous. Old branches often with 6 deep longitudinal grooves. Young branches often with retrorse stiff hairs. Leaves opposite, margin entire or dentate (or sometimes lobed on vigorous shoots), shortly petiolate, estipulate. Petioles of opposite leaf pairs dilated and connate at base, enclosing winter buds. Inflorescence a terminal congested thyrse of sessile cymes; cymes 1-3-flowered. Calyx of 4 or 5 sepals, persistent, spreading, narrowly oblong to elliptic. Corolla white, pale rose, or sometimes reddish, hypocrateriform and ± zygomorphic, 4- or 5-lobed; corolla tube usually without distinct swelling at base, glandular inside. Stamens included, didynamous, inserted at base or middle of corolla tube; anthers yellow, introrse. Ovary usually 3-locular, 2 locules with 2 series of sterile ovules and 1 locule with a single fertile ovule; style filiform; stigmas green, capitate, mucilaginous. Fruit a leathery achene, oblong, crowned with persistent calyx lobes; seed subterete, testa membranous; endosperm fleshy.

Six species: Afghanistan, China, NW India, Japan, Korea, Kyrgyzstan, Nepal, Russia (Far East); three species (one endemic) in China.

This group was first published by Rehder (in Sargent, Pl. Wilson. 1: 118. 1911) as Abelia sect. Zabelia. It was described in honor of Zabel who was the first to delimit the genus Abelia into sections (Mitt. Deutsch. Dendrol. Ges. 2: 33. 1893). The phylogeny of this group was further studied by Makino and supported by the studies of Ikuse and Kurosawa (Notes on Sect. Zabelia Rehder of the genus Abelia, J. Jap. Bot. 29(4): 11. 1954), and later by Fukuoka (Phylogeny of the Tribe Linnaeeae, Acta Phytotax. Geobot. 23: 82. 1968). The genus Zabelia was segregated from Abelia based on pollen, wood anatomy, inflorescence structure, and karyology (Makino, Makinoa 9: 175. 1948; cf. Hisauchi & Hara, J. Jap. Bot. 29: 143. 1954).

Species Complex

2-3. Zabelia biflora species complex

Shrubs deciduous, 2-3 m tall. Petiole 4-7 mm, sparsely hispid. Leaf blade narrowly ovate or obovate to lanceolate, 30-80 × 5-30 mm, abaxially glabrous but with stiff hairs on veins, adaxially sparsely pubescent when young, base cuneate to ob­tuse, margin entire or with 1-6 pairs of teeth, apex acute to long acuminate. Inflorescence terminal, of paired flowers (occa­sionally more due to supernumerary flowers axillary to brac­teoles); flowers sessile but long pedunculate, peduncles often appearing ± fused; peduncles 0-12 mm; flowers with 3 bracts at base of each ovary; bracts 1-6 mm. Sepals 4, ovate-lanceolate or obovate. Corolla white sometimes tinged red abaxially, 4-lobed; lobes orbicular, 1/3 or 1/5 as long as tube; tube pu­bescent inside. Stamens 4, didynamous, included. Ovary to 8 mm, with sparse, stiff hairs; styles long, equaling corolla, slen­der; stigmas capitate, not exserted from corolla tube. Achene 1-1.5 cm, crowned with 4 persistent and slightly enlarged sepals. Fl. Apr-Jun, fr. Aug-Sep.

Scrub, forests, grasslands; 800-3700 m. Anhui, Fujian, SE Gansu, Guizhou, Hebei, Henan, Hubei, Hunan, Jiangxi, Liaoning, Nei Mongol, S Ningxia, Shaanxi, Shanxi, Sichuan, Xizang, Yunnan, Zhejiang [Japan, Korea, Russia (Far East)]. The Zabelia biflora species complex was revised by Nakai (J. Jap. Bot. 13(8): 1-12. 1937) who distinguished 11 species. We cur­rently recognize two species in China. Most of the differences between taxa were based on the length of the peduncles, bracts, and bracteoles, which are highly variable. Classi­fication of Zabelia biflora is complex and needs to be investigated.

Lower Taxa

• Zabelia biflora (Turczaninow) Makino
• Zabelia dielsii (Graebner) Makino
• Zabelia triflora (R. Brown) Makino