Leye willow (Carrierea leyensis) found in limestone area of Guangxi, China, resembles Carrierea dunniana

NEWS - Leye willow (Carrierea leyensis Z.C.Lu & W.B.Xu, sp. nov.) of the Salicaceae found in the limestone area of Guangxi, China, resembles C. dunniana H.Lév, but is evergreen, with shorter petioles and serrated or glabrous when old. The leaf blade is elliptical with a wedge-shaped base; the inflorescence is shorter and the capsule is smaller.

Carrierea Franchet (1896) is a small genus in the Salicaceae distributed from southern China to northern Vietnam. Four species have been published in Carrierea previously, but C. rehderiana Sleumer as a synonym of C. calycina Franch. (1896) and C. vieillardii Gagnep. as a synonym of Itoa orientalis Hemsl.

Zhao-Cen Lu and Wei-Bin Xu from the Chinese Academy of Sciences in Guilin conducted an investigation from July 2023 to May 2024 and discovered the unusual plant. After careful examination of the morphological characters of the specimen, they confirmed that the specimen is a species new to science.

C. leyensis is a tree or small tree, monoecious, evergreen, 5–12 m tall; bark gray-brown; branchlets grayish, with white lenticels and leaf marks, tomentose, glabrous when old; winter buds conical, scales hairy; stipules absent.

Petiole 3–8 mm long, tomentose to glabrous when old; leaf blade greenish abaxially, deep green adaxially, glabrous, elliptic, (2.8–)4–9.5(–12.5) × 1.7–4.6 cm, leathery or thinly leathery, both surfaces glabrous or abaxially sparsely appressed-villous along midveins.

Weakly 3-veined at base, lateral veins 5–8 pairs, veins distinct on both sides, midvein raised below, base cuneate, margin remotely serrate, with spheroidal to torus-shaped glands at the tips of the teeth (salicoid teeth), apex acuminate to long acuminate.

Terminal or axillary inflorescence, 2–11-flowered, rarely single flower axillary, 1.8–4.5 cm long including flowers, tomentose, pistillate flowers in terminal part of inflorescence, staminate ones in lower part; bracts ovate-lanceolate, 1–1.35 cm long, papery, both surfaces sparsely to densely tomentose.

Pedicels 0.5–2.5 cm long, 2-bracteolate near middle; bracteoles similar to bracts, opposite, narrowly oblong, 3–7 mm long, papery, both surfaces sparsely to densely tomentose. Sepals (2 or 3 rare) 4–5, valvate, ovate-deltoid to oblong, 3.5–8 × 2–3 mm, papery, both sides tomentose, apex acute.

Petals absent. Staminate flowers: smaller than pistillate flowers, stamens with filaments unequal in length, 2–3 mm long, glabrous; anthers ca. 0.5mm long.

Pistillate flowers: staminodes like stamens but much reduced; ovary superior, elliptic, densely tomentose, 0.6–1 cm long; placentas 3 or 4; styles 3 or 4, 0.5–1 mm long, connate at least at base to form a column, sparsely tomentose like the ovary; stigmas reflexed, drying black, flattened, triangular, 2–3 mm long, irregularly lobed, glabrous.

Capsule fusiform, slightly curved, 1.7–2.7 cm long, 5–9 mm in diam., tomentose, valves splitting from both apex and base; fruiting pedicel stout, 1–2.8 cm long; seeds compressed, including wing 9–12 mm long; sterile seeds smaller.

C. leyensis differs from C. dunniana in being evergreen; petioles shorter, only 3–8 mm long, and tomentose or glabrous when old; leaf blades elliptical with a wedge-shaped base; inflorescence shorter; flowers smaller; and capsules smaller.

The specific epithet ‘leyensis’ refers to the locality where the new species was collected. Flowers April to May (spring) and fruits July to October (summer to autumn). The specimen was collected from Leye County, Baise City, Guangxi, China. It grows sporadically in forests on limestone slopes at elevations of 1100–1350 m.

Related species include Handeliodendron bodinieri (H.Lév.) Rehder, Pistacia chinensis Bunge, Pittosporum tonkinense Gagnep., Machilus cavaleriei H.Lév., Triadica rotundifolia (Hemsl.) Esser, Jasminum lanceolaria Roxb., Eriobotrya seguinii (H.Lév.) Cardot ex Guillaumin, Carex brunnea Thunb., Ophiorrhiza and Carpinus.

Original research

Lu Z-C, Liu Z-R, Mo M-L, Chang S-L, Xu W-B (2024). Carrierea leyensis, a new species of Salicaceae from limestone areas of Guangxi, China. PhytoKeys 248: 305-313, DOI:10.3897/phytokeys.248.129824

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