Toxicodendron oligophyllum S. L. Tang, Liang Ma & S. P. Chen, 2022

Tang, Shu-Ling, Chen, Xin-Yan, Ma, Liang, Ni, Bi-Yong, Pan, Biao-Zhi & Chen, Shi-Pin, 2022, Toxicodendron oligophyllum (Anacardiaceae), a new species from Fujian, China: evidence from morphological and molecular analyses, Phytotaxa 539 (1), pp. 55-61 : 58-60

Toxicodendron oligophyllum S. L. Tang, Liang Ma & S. P. Chen , sp. nov. ( Fig. 2 & Fig. 3 : A–G).

This new species is similar to T. acuminatum (DC.) C. Y. Wu & T. L. Ming , T. succedaneum (L.) Kuntze and T. sylvestre (Sieb. & Zucc.) Kuntze , but can be distinguished by its glabrous branchlet, leaf and inflorescence, 3–5 leaflets, and the length of inflorescence equal to the leaf.

Type: — CHINA, Fujian: Yongtai County, terrestrial in evergreen broad-leaved forests on cliffs formed by weathering of volcanic rocks, alt. 733 m, May 2019, MA 20190519 (holotype, FJFC!; isotype, CSH!) .

Deciduous trees or small trees to 12 m tall; phloem with white latex and turning black upon air exposure; branchlets and buds purple-brown, glabrous. Petiole 3–5 cm, petiole and rachis slender, glabrous; leaf blade imparipinnately compound, 10–15 cm long; leaflets 3–5, opposite; leaflet petiolule indistinct or 2–7 mm long; leaflet blade ovate to ovate-elliptic, 5–7 × 2–4 cm, thinly leathery, glabrous on both surfaces, adaxially dark-green, abaxially glaucous, margin entire, base ± oblique, broadly cuneate or rounded, apex acuminate to caudate-acuminate; lateral veins 15– 20 pairs, slightly prominent on both surfaces. Inflorescence paniculate, 10–15 cm long, many branched, glabrous. Pedicel 4–5 mm long; flowers yellowish green, ca. 2 mm in diam. Calyx glabrous, lobes broadly ovate, ca. 1 × 0.8 mm, obtuse apically. Petals oblong, ca. 2 × 1.5 mm, obtuse apically, with ± conspicuous featherlike venation pattern, revolute at anthesis. Stamens exserted; filaments linear, ca. 2 mm long; anthers ovoid-oblong, ca. 1 mm long. Disk 5-lobed. Ovary globose, ca. 8 mm in diam., glabrous. Drupe large, asymmetrical, ca. 8 mm in diam., compressed, apex eccentric; epicarp thin, glabrous, lucid, separating; mesocarp thick, waxy, with brown longitudinal resin ducts; endocarp compressed, ca. 3 × 5 mm.

Phenology: The species blooms from May to June and fruits from June to October.

Etymology: The species epithet refers to its characteristic of having the least number of leaflets in this genus. Chinese name: Ṫ叶¨ (shao ye qi).

Distribution and habitat: It mainly grows on cliffs formed by the weathering of volcanic rocks at altitudes of 300– 900 m. It is so far only known from the type locality, i.e. Yongtai County, including Chibi Village, Tianmen Mountain Ecological Scenic Spot and Ximen Village, Fujian Province of China.

Conservation State: At present, the new species is only found from its type locality with five populations. Each population of T. oligophyllum is comprised of approximately 200 mature individuals. We believe further observation is needed to find out other locality of the species and therefore, yet we suggest the species to be assessed as Data Deficient (DD; IUCN, 2019).

Figures

FIGURE 2. Toxicodendron oligophyllum S. L. Tang, Liang Ma & S. P. Chen. A. Flowering branch; B. Infructescence; C. Flower, front view; D. Flower, side view.

FIGURE 3. Toxicodendron oligophyllum and related species. T. oligophyllum (A. Habitat; B. Flowering branches; C. Leaf, abaxial view; D–E. Flowers; F. Infructescence; G. seed); T. sylvestre (H. Branchlets, I. Leaves); T. succedaneum (J. Branchlets, K. Leaves).