Alocasia lihengiae C.L. Long & Q. Fang, 2020

Fang, Qiong, Yang, Jun & Long, Chunlin, 2020, Alocasia lihengiae, a new species of Araceae from Southern Yunnan, Phytotaxa 436 (2), pp. 97-103 : 98-102

Alocasia lihengiae C.L. Long & Q. Fang , sp. nov. ( Table 1 , Figure 1 )

Similar to A. odora in leaf blade shape and primary lateral veins, but different in having a milky yellow appendix, and especially the purple- pink spathe. It differs from A. hypnosa by having triangular blade rather than triangular- sagittate blade, having fewer lateral veins but more conspicuous collecting veins, shorter petiole, more massive plant with more stolons, and purple-black stigma instead of pale green stigma.

Type: — CHINA. Yunnan: Xishuangbanna Dai Autonomous Prefecture, Jinghong City, Jinuoshan Township , 960 m a.s.l., 22º13’N, 100º53’E, 18 August 2018, Long 2018107 (flowering) (holotype KUN!; isotype KUN!) .

Pachycaul herbs, terrestrial, massive, up to 2 m, seasonally dormant, with slightly milky latex. Stem erect, rhizome 10–15 cm long, 5–13 cm in diam; stolons multiple per plant, slender, pale green, 45–50 cm long, internodes cylindric, 3–5 cm long, to 1 cm in diam, normally no tubercle at the end of stolon. Leaves several to rather many together, clustered at tips of stems of larger plants; petiole 60–100 cm, 6 cm diam. at base, 1.2–2 cm diam. at top, light greenish, glossy; petiolar sheath convolute at base, sheath reaching middle of the petiole, membranous; lamina outline triangular, cordate-sagittate or cordate-ovate, 55–63 × 40–45 cm, margins undulate, apex shortly acuminate; primary lateral veins 6–8 on each side, bulge and conspicuous, interprimary veins forming well-defined interprimary collective veins, the secondary veins from the basal primary veins are conspicuous. Inflorescences 2 or 3 per leaf, subtended by membranous cataphylls; peduncle stout, bright green, cylindrical, 45–50 cm long, 1.5–1.8 cm in diam., exceeding cataphylls at anthesis; Spathe 20–30 cm, constricted ca. 1/6 of way from base; proximal part green, fusiform; Spadix 22–26 cm, shorter than spathe, shortly stipitate; tube part 9 cm long, eave part 20–24 cm, yellowish white at base and back, other parts are purple; female zone 1.2–1.5 × ca. 3–4 cm; pistil pale yellow, ca. 1.2–1.5 cm in diam.; stigma sessile, weakly 2-lobed, lobes blunt, yellow, sterile zone yellowish white at base, 4–5 cm in length, ca. 0.8–1.2 cm in diam.; male zone whitish, cylindric, 4 × ca. 2 cm; synandria rhombic-hexagonal, ca. 1.2–1.5 cm in diam.; appendix milky yellow, oblong conic, 12.5 cm; Fruiting spathe ca. 4–5 cm, 2–3 cm in diam. Fruit green white, globose, ca. 4 mm in diam. Stigma persistent, purple-black.

Distribution and habitat: —So far known only one population from Jinuo Mountains, Jinghong, Xishuangbanna, Yunnan, China. Growing on the limestone, in an open roadside habitat, as part of a larger area of karst landscape.

Phenology: —Flowering from June to August.

Etymology: —Named in honor of Prof. Li Heng, a Chinese aroider who has made significant contributions to our knowledge of the family Araceae .

Additional specimens examined (paratypes): — CHINA. Yunnan: Xishuangbanna Dai Autonomous Prefecture, Jinghong City , 960 m a.s.l., 22º13’N, 100º53’E, 19 July 2018, C. L. Long 2018108-1, Long2018108-2, Long2018108-3, Long2018108-4, Long2018108-5, Long2018108-6, Long2018108-7 (fruiting) ( KUN!). Specimens collected from the same location but different collections .

Notes: —With the inconvenient conservation of fresh specimens and the absence of extensive fieldwork, the descriptions of many newly discovered species are left inadequately described. While there is no standard form for infrageneric taxonomic classification ( Boyce 2008), the genus is uniquely defined by characteristics such as milky acrid sap, staminate flowers forming synandria, and fruits ripening to orange scarlet berries ( Zulhazman et al. 2017), basal placentas, odorless fruit with bird dispersal syndromes ( Boyce 2008).

After examining herbarium specimens, we believe that Alocasia lihengiae is similar to A. odora and A. hypnosa . However, A. lihengiae can be distinguished easily from A. odora by the purple-pink spathe lamina and seasonally dormant habit. It is also different from A. hypnosa in upwards basal lobes, conspicuous lateral veins, milky yellow appendix, with more slender stolons, normally without tubercle at the end of stolon and especially persistent purpleblack stigma. A detailed comparison is presented in Table 1. A key to species of Alocasia occurring in China is provided.

Morphologically, A. lihengiae is similar to A. odora and A. hypnosa , it shows mixed traits of each but not both. While it seems a hybrid of A. odora and A. hypnosa , distribution of A. hypnosa has not been seen in the Jinuo Mountains so far, and there is no observation of pollinators yet. In addition, there is only one population of A. lihengiae , thus hybridity is unlikely to happen. However, some level of sterility is observed ( Figure 2A ), suggesting a limited selfpollination and an absence of pollinators. This may explain its so far isolated occurrence.

Figures

FIGURE 1. A. Habitat of Alocasia lihengiae. B. Inflorescences 2 or 3 together. C–E. Spathe at anthesis from different angle. F–I. Spathe from different angle with lamina as background. J. Triangular leaf blade. Photos by C. L. Long.

FIGURE 2. A. Fruits of Alocasia lihengiae with immature green berries. B-E. Spathe at anthesis. Photos by C. L. Long.