Lonicera tricalysioides Wu ex Hsu & Wang (1979: 77)

Zeng, You-Pai, Luo, Yu-Feng & Yang, Qin-Er, 2021, Reinstatement of Lonicera tricalysioides (Caprifoliaceae) as a distinctive species from China, Phytotaxa 490 (2), pp. 183-190 : 184-187

Lonicera tricalysioides Wu ex Hsu & Wang (1979: 77) . Figs. 1‒3 .

Type:— CHINA. Guizhou province: Chishui county, Yuanhou district (now Yuanhou town ), Hutou Shan (literally “ Tiger Head Mountain ”), 28°18′39″N, 105°55′44″E, on rocks in ravine, alt. 850 m, 13 September 1959, Bijie Exped. 1221 (holotype KUN!; isotype PE!). Fig. 1 .

Description:—Shrubs, evergreen; stems pendulous or obliquely descending, ca. 1.5 m long. Winter buds with several pairs of acute scales. Branches with solid pith, glabrous, ca. 3 mm in diameter. Leaves oblong-lanceolate to ellipticoblong, 7‒15 cm long, 3‒5 cm broad, leathery, glabrous on both surfaces, adaxially usually shiny, midvein flat or slightly impressed, base rounded to broadly cuneate, apex long caudate-acuminate. Inflorescences axillary, paired flowers; peduncle 1.2‒2.8 cm long, glabrous; bracts lanceolate, ca. 3.5 mm long; bracteoles cupular, completely enclosing paired ovaries, sparsely glandular. Neighboring 2 ovaries free. Calyx cupular, forming a collarlike emergence at base, overlapping apex of bracteoles; lobes ovate, glabrous, apex obtuse. Corolla greenish yellow, tinged with purple, funnelform, ca. 10 mm long; tube shallowly gibbous at base, inside villous, outside glandular; lobes almost regular, broadly ovate, ca. 3 mm long, apex obtuse. Anthers exserted. Style exserted, proximally villous; stigmas capitate, hemispherical. Fruit green to yellowish, not translucent when mature, globose, ca. 3 mm in diameter; seeds 1‒4, pale yellow, ovoid or subglobose, sometimes compressed, ca. 2 mm long, smooth.

Distribution and habitat:— Lonicera tricalysioides is currently known from northern Guizhou (Chishui county) and southeastern Sichuan (Gulin county), China ( Fig. 4 ). It grows on rocky cliffs in ravine at altitudes of 850‒1130 m.

Phenology:—Flowering from April to May; fruiting from June to October.

Additional specimens examined:— CHINA. Sichuan: Gulin, near Huangjing town, Y.P. Zeng & Y.F. Luo 296 (IBSC), Y.P. Zeng & Y.F. Luo 477 (IBSC).

Conservation status:— Lonicera tricalysioides is currently known only from Chishui county in Guizhou province (the type locality) and Gulin county in Sichuan province, China, two closely neighboring locations in the western Dalou Shan region. The Chishui population is little known. The Gulin population, consisting of no more than 50 individuals, is situated at a provincial nature reserve. The only risk of this population may come from roadbuilding. The discovery of more populations of L. tricalysioides is to be expected as the botanical exploration proceeds in the Dalou Shan region. The conservation status of L. tricalysioides should be considered as “Data Deficient (DD)” before adequate information of this species is acquired ( IUCN Standards and Petitions Committee 2019).

Notes:— Lonicera tricalysioides is readily distinguishable from L. ligustrina var. pileata ( Figs. 5 , 6 ) by having glabrous young branchlets, oblong-lanceolate to elliptic-oblong leaves which are longer (7‒15 cm), apex long caudateacuminate, base rounded to broadly cuneate, glabrous on both surfaces, with the midvein flat adaxially, not raised, and by having longer peduncle (1.2‒2.8 cm) and green to yellowish, not translucent fruits when mature. In L. ligustrina var. pileata , young branchlets are densely covered with stiff and upwardly recurved hairs; leaves are ovate, oblonglanceolate or rhombic-oblong, 0.4‒8 cm long, apex obtuse, base usually cuneate or rounded, abaxially subglabrous or sparsely hairy, with the midvein raised adaxially; peduncle is 0.3‒0.5 cm long; fruits are purple or white, translucent when mature. A detailed comparison between these two taxa is given in Table 1. From another two varieties of L. ligustrina, var. ligustrina and var. yunnanensis Franchet (1896: 317) , L. tricalysioides differs immediately, among other characters, by having larger (7‒15 cm vs. 0.4‒8 cm long) leaves and green to yellowish, not berry-like (vs. purple or red, berry-like) fruits.

In habitat preference, Lonicera tricalysioides grows on rocky cliffs in ravine, whereas L. ligustrina var. pileata usually grows along watersides, in moist places in sparse forests or scrubs on slopes ( Hsu & Wang 1988).

Figures

FIGURE 1. Holotype (A) and isotype (B) sheets of Lonicera tricalysioides.

FIGURE 2. Lonicera tricalysioides in the wild (Gulin county in Sichuan province, China). A. Habitat. B. Habit.

FIGURE 3. Lonicera tricalysioides in the wild (Gulin county in Sichuan province, China).A. Longitudinal section of stem. B. Branches. C. Leaf (left: adaxial side; right: abaxial side). D. Pair of flowers. E. Pair of flowers, the corollas mostly removed. F. Flower (top view). G. Longitudinal section of flower. H. Style and stigma. I. Fruits. J. Seeds.

FIGURE 4. Distribution of Lonicera tricalysioides (●). Arrow indicates the type locality, i.e. Chishui county in Guizhou province, China.

FIGURE 5. Type sheets of Lonicera ligustrina var. pileata.

FIGURE 6. Lonicera ligustrina var. pileata in the wild (Gulin county in Sichuan province, China). A. Habitat. B, C. Flowering branches.