Hoya yingjiangensis J.F. Zhang, L. Bai, N.H. Xia & Z.Q. Peng, 2015

Zhang, Jing-Feng, Bai, Lin, Xia, Nian-He & Peng, Ze-Qiu, 2015, Hoya yingjiangensis (Apocynaceae, Asclepiadoideaea), a new campanulateflowered species from Yunnan, China, Phytotaxa 219 (3), pp. 283-288 : 284-287

publication ID

https://doi.org/ 10.11646/phytotaxa.219.3.8

persistent identifier

https://treatment.plazi.org/id/BD2787DC-FF8C-5B64-FF5C-FCED22A6FEBA

treatment provided by

Felipe

scientific name

Hoya yingjiangensis J.F. Zhang, L. Bai, N.H. Xia & Z.Q. Peng
status

sp. nov.

Hoya yingjiangensis J.F. Zhang, L. Bai, N.H. Xia & Z.Q. Peng View in CoL , sp. nov. ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 )

Similar to H. collettii in that the habit is shrubby and the whole plant glabrous, lamina are succulent, peduncles are short, corollas are broad and campanulate, and sepals are elliptic and concave, but differs in that: 1) internodes are 4–7 cm long (versus shorter than 2 cm in H. collettii ), 2) leaf blades are oblanceolate with bases cuneate (versus linear oblong with bases rounded in H. collettii ), 3) flowers are borne one per peduncle (versus flowers numerous per peduncle in H. collettii ).

Type: — CHINA. Yunnan Province: Dehong Dai Zu Jingpozu Zizhizhou, Yingjiang Xian, epiphytes on canopy of big trees in montane rainforest, on the China-Myanmar border, elev. 1600 m, 9 August 2014, L. W. Wu 20140901 (holotype, IBSC!)

Shrubby epiphyte, forming a highly branched clump, sap milky-white. Stems pendulous, up to 1.2 m long, 5–6 mm diam., glabrous, bark dark green when young, turning pale brown with conspicuous black spots when mature, adventitious root not present; internodes 4–7 cm long. Leaves opposite, petiole grooved, 6–8 mm × 1–1.5 mm, glabrous, green; lamina oblanceolate, 6–10 × 2.1–2.5 cm, fleshy, succulent, base cuneate, usually decurrent to petiole, apex caudate, glabrous on both sides, green adaxially, greyish green and flecked with irregular small black spots abaxially; when fresh, lateral veins inconspicuous on both sides, mid-vein ribbed abaxially, when dry, lateral veins prominently impressed, pinnate, secondary veins 3–4 on each side, basal most run near the lamina margin, upper most held at an acute angle to mid vein, anastomosing along the lamina margin. Inflorescence interpetiolar, consisting of a single flower, bracts interpetiolar, subulate, to 2 mm long, peduncles to 1.5 mm long, dark green, annual deciduous; bracteole borne opposite the bract, broadly triangular, 0.5 × 0.25 mm, glabrous, green; pedicel positively geotropic, to 2 cm long, glabrous, pale green calyx with five sepals, sepals elliptic, 6–7 × 3–4 mm, deep concave on the upper part, apex obtuse, glabrous on both sides, creamy white to pale green; corolla campanulate, 1.5–1.6 cm tall, 2.2–3 cm diam., glabrous throughout externally, internally lanate in the middle, hairs inconspicuous on the margin, creamy yellow, corolla tube ca. 1.5 × 1.4–1.6 cm, lobes broadly triangular, 10–11 × 7–8 mm, revolute, apices acute; gynostegium ca. 6.5 mm tall, corona lobes five, adnate vertically to gynostegium, fleshy, corona column short, 2 mm long, 4 mm diam. at apex, 2.5 mm diam. at base, glabrous, corona staminal ca. 9 × 8–9 mm, corona lobes very thick, 5 mm tall, apically oblong, concave, short, ca. 8 × 6.5 mm, inner process acuminate, terminating in an erect, acute tip 4 mm taller than the anthers; outer process acute, margin revolute, longitudinally grooved basally; pollinarium erect, ca. 1290 μm long, pollina oblong, compressed, with round apex and base, and prominent pellucid margin, ca. 970 × 460 μm, corpusculum ca. 450 × 250 um, translator 220–245 μm long; ovary bi-carpellate, conical, 4–5 mm long, each carpel ca. 1.2 mm wide at base, light green. Fruit and seeds unknown. All measurements from type material prior to pressing.

Etymology:— The specific epithet is derived from the name of type locality of the new species, Yingjiang Xian in Yunnan Province, China.

Distribution, habitat and phenology:— Hoya yingjiangensis is only known from Yingjiang Xian in Yunnan, where it grows as an epiphyte in the canopy of large rainforest trees as tall as 20 m, in tropical montane forest at 1600 m elevation. This species flowers from Mid-August to late-September. According to local people, fruiting starts in late September.

IUCN assessment:— Hoya yingjiangensis is currently known only from the type locality. No specimens of this species were encountered during an extensive examination of herbarium material at herbaria HITBC, IBSC, KUN, and PE. The IUCN status is proposed as “DD” (Data Deficient), according to the IUCN (2012) guidelines.

Notes: —Depending on the species, the number of flowers in a pseudo-umbel of Hoya can vary from only one to several dozens ( Hooker 1883; Tsiang & Li 1977; Li et al. 1995; Lamb et al. 2014) and the peduncles from annual to perennial. Perennial peduncles are more common. They remain persistent after abscission of flowers or fruits and are able to produce flowers in succession for several years. The region of pedicel attachment is characterized by pedicel scars after abscission of flowers or fruits and in some species this region can grow up to 9 cm long after producing dozens of individual flowers ( Lamb et al. 2014). Annual peduncles abscise after flowering or fruiting. The pseudo-umbel of H. yingjiangensis consists of only a single flower. Its peduncles belong to the annual deciduous type and are extremely reduced.

the protologue by Collett & Hemsley (1890) and measurement of the specimen Collett 833 [K], which belongs to original material of this species.)

Hoya yingjiangensis is mostly similar to H. collettii . A comparison of morphology of the two species is provided in Table 1. Both species were collected from rather high elevations ( Collett & Hemsley 1890). The type locality of H. yingjiangensis is less than 200 km north of that of H. collettii . Hoya yingjiangensis is the only species in this region that also exhibits large campanulate corollas. However, it is immediately distinguishable in that the pseudo-umbel consists of only a single flower.

L

Nationaal Herbarium Nederland, Leiden University branch

W

Naturhistorisches Museum Wien

IBSC

South China Botanical Garden

Kingdom

Plantae

Phylum

Tracheophyta

Class

Magnoliopsida

Order

Gentianales

Family

Apocynaceae

Genus

Hoya

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