Guihaia heterosquama X. Y. Li, 2019

Li, Xianyuan, Peng, Hui, He, Xi, Li, Zhineng & Wu, Di, 2019, Guihaia heterosquama, a new species of coryphoid palm (Arecaceae) from Chongqing, China, Phytotaxa 405 (5), pp. 248-254 : 248-253

Guihaia heterosquama X. Y. Li , sp. nov. ( Figs. 1–3 )

Similar to Guihaia grossifibrosa and G. argyrata in the presence of reduplicate palmate leaves, but differing from all the reported species in its powdery and membranous patchy leaf scales on the abaxial surface of the lamina, basally reticulated and distally whisker-like leaf sheath fibers, glabrous hastula and the presence of a pistillode in the male flower.

Type: — CHINA. Chongqing: Fuling District , on the karst limestone hills, 29°29’54.48″N, 107°34’59.50″E, elev. ca. 1170 m, 4 June 2018, Xianyuan Li 2018002 (flower, ♀, holotype, HWA!) ; ibidem, 4 June 2018, Xianyuan Li 2018001 (flower, ♂, paratype, HWA!) ; ibidem, 20 August 2017, Xianyuan Li 2017005 (fruit, paratype, HWA!) .

Plants shrubby, dioecious. Stems solitary, to 1.5 m tall, ca. 8–15 cm in diam, erect or leaning, densely covered with persistent petiole bases. Leaf sheath fibers soft, dark-brown, basally netlike, distally separating and becoming whisker-like; petioles glabrous, 40–65 cm in length, ca. 8–10 mm in width, with smooth margins; adaxial hastula well-developed, semicircular, glabrous, 8–10 mm × 10–12 mm, abaxial hastula tiny but clearly visible; leaf blade palmate, plication reduplicate, deeply divided 2/3–3/4 to base; segments 22–27, linear-lanceolate, 43–55 cm × 1.2–2.9 cm, adaxially green without scales, abaxially slightly silvery white with powdery and membranous patchy scales. Inflorescences axillary within crown of leaves, paniculate, with 3–4 orders of branching, ca. 0.6 m in length; prophyll tubular, 2-keeled; peduncular bracts 2, glabrous, keel absent; rachis bracts 2–5, similar to peduncular bracts; flowers unisexual, borne singly along rachillae, sessile; Male flowers with 3 pistillodes, ca. 3 mm in length; calyx cupulate, ca. 1 mm in length, 3-lobed, glabrous; corolla ca. 3 mm in length, 3-lobed, lobes basally connate up to 1/2–2/3 their length, glabrous, 1 spheroidal appendage in each lobe at the apical region and on the inside; stamens 6 in 2 whorls, filaments adnate to the corolla, anthers ca. 0.3 mm in diameter; Female flowers with 6 staminodes, ca. 3.5× 1.5 mm; calyx cupulate, ca. 1–1.5 mm in length, 3-lobed, glabrous; corolla ca. 3× 1.5 mm, similar to corolla of male flowers; carpels 3, distinct, glabrous, ca. 0.6× 0.4 mm. Fruits blue-black, ellipsoid to ovoid, ca. 6–8× 4–5 mm. Flowering from May to June, fruiting in August to September.

Distribution and ecology:— The single known locality for Guihaia heterosquama is Shijia Valley, Chongqing, China (ca. 1170 m elevation) with the following woody associates: Cyclobalanopsis gracilis (Rehd. et Wils.) Cheng et T. Hong , Pittosporum truncatum Pritz. , Hypericum monogynum L., Carpinus viminea Wall. The plants of G. heterosquama are clustered on the continuous karst limestone cliff in subtropical evergreen broad-leaf forest.

Etymology:— The species name G. heterosquama refers to its leaf scales features, and the epithet “ heterosquama ” refers to two different types of scales on leaf blade abaxially. “fiḆƂƜử (Yì Lín Shí Shân Zông)” is suggested as a suitable China name for it.

Similar species: — Guihaia heterosquama is immediately distinguishable from Guihaia lancifolia in its palmately divided rather than undivided lanceolate leaf. It is similar to G. grossifibrosa and G. argyrata both in the shape of the leaf blade and the structure of the flowers, but it can be easily distinguished by its powdery and membranous patchy scales (vs scarce powdery scales of G. grossifibrosa , dense silvery white hairy scales of G. argyrata ) ( Fig. 4 A-C), the soft and basally reticulated but distally whisker-like leaf sheath fibers (vs stout, curved, remaining joined at apex of G. grossifibrosa , stiff, erect, separating and becoming spinelike at apex of G. argyrata ) ( Fig. 4 D-F), glabrous hastula (vs hastula with caducous fringed hairs of G. grossifibrosa and G. argyrata ) ( Fig. 4 G-I). Notably, Guihaia heterosquama differs from all the reported species of Guihaia by the presence of a distinct pistillode in the male flower. The significant differences among the new species and the other two similar species of Guihaia are listed in Table 1.

Figures

FIGURE 1. A–F Guihaia heterosquama. A. Habit. B. Sheath fibers. C–D. Male Flower. E–F. Female Flower. Scale bar: A = 10 cm, B = 5 cm, C–F = 1 mm. Illustration by Xi He.

FIGURE 2. Guihaia heterosquama. A. Habitat. B. Plant. C. Scales on leaf blade abaxially (Bar = 0.5 mm). D. Male inflorescence. E. Female inflorescence. F. Fruit. Photographed by X. Y. Li.

FIGURE 3. Guihaia heterosquama. A–C. Male flower; D–G. Female Flower. Bar = 0.5 mm Photographed by Hui Peng.

FIGURE 4. The significant differences among Guihaia heterosquama (A, D, G), G.grossifibrosa (B, E, H) and G. argyrata (C, F, I). A–C Leaf scale; D–F Leaf sheath fiber; G–I Hastula. Bar = 0.5 mm. Photographed by X. Y. Li.