Hypericum liboense M.T.An & T.R.Wu, 2024

Wu, Tian-Rou, Xu, Jian, An, Ming-Tai, Yu, Jiang-Hong, Liu, Feng & Chen, Zheng-Ren, 2024, Hypericum liboense (Hypericaceae), a new species from Guizhou, China, PhytoKeys 237, pp. 37-49 : 37

Hypericum liboense M.T.An & T.R.Wu sp. nov.

Fig. 2

Type.

China, Guizhou Province, Libo County, Maolan National Nature Reserve , elev. 947, 25°16'N, 107°57'E, 21 April 2022, Jian Xu, Mingtai An and Tianrou Wu 220421(Holotype: GZAC-LB-0001, Isotype: GZAC-LB-0002) .

Diagnosis.

This species is similar to H. monogynum in terms of morphology. The main difference between the two species is that the leaves of H. liboense are sessile and semi-clasped (vs. leaves sessile or brachypetiolate). The leaves of H. liboense are long elliptical to long circular, and the edges are whole and wavy (vs. oblanceolate or elliptic to long circular, flat). H. liboense leaves are thickly papery to thinly leathery (vs. thickly papery), with a white powder on the abaxial side leading to a grey-white appearance (vs. abaxially without grey). Main lateral veins of leaves 8-15 pairs (vs. 4-6 pairs), with the midvein on both sides convex, the main lateral veins obvious branches from the midvein, the main lateral veins and tertiary vein forming an obvious network and obviously sagging (vs. tertiary vein obscure and not sunken). Inflorescences with 1-3 flowers (vs. 1-15(-30) flowers), calyx are elliptic or broad-ovate (vs. broad or narrowly elliptic or oblong to lanceolate or oblanceolate), 10-14 mm long, 4-6 mm wide (vs. 4.5-13 mm long and 1.2-2 mm wide), and veins obvious (vs. obscure) (Table 2 ).

Description.

Plants Erect shrub, 0.5-1.3 m tall. Young branches reddish brown with a light white powder. Old branches dark reddish-brown or grey, cylindrical, with a lumpy rind after cracking off, and the cortex light red. Leaves opposite, sessile, with semi-clasping branchlets. The leaves are long elliptical to long circular, 4-8 cm long and 2-4 cm wide, with the middle entire part of the leaf usually the widest, the apex blunt round, with a fine cusp; leaf blade base cuneate to rounded, margin entire and slightly ruffled; thickly papery to thinly leathery, glabrous, the surface of the leaves green or dark green, the back of the leaves white and greyish-white; the main lateral veins of the leaves in 8-15 pairs, the midvein raised on both sides, and the base reddish; main lateral veins and midvein branching obviously, main lateral veins and tertiary vein forming an obvious network and concave on the leaf surface; wholly punctiform glands. Inflorescence with 1-3 flowers, emanating from the first segment of the stem; peduncle yellow-green, 1.3-3 cm long. Flowers 4-7 cm in diameter; bud ovular, apex subacute. Calyx 5, free, ovate to broadly ovate, 1-1.4 cm long, 0.4-0.6 cm wide, wholly punctiform glands, apex acute to rounded, entire margin, base light green, margin purplish red, midvein and veining obvious, and calyx enlarged in the fruit stage. Petals 5, yellow, without flush, open, triangular obovate, slightly curved, 2.8-3.5 cm long, 1.6-2.2 cm wide, approximately, margin entire, glandular. Stamens in 5 fascicles, each with 23-40 stamens, 1.3-3.4 cm long, several times the length of the petal, anthers yellow to dark orange, with glands. Ovary ovulate or sub-globular, 3-5 mm long, 2.5-5 mm wide. Style 1.3-2.2 cm long, styles partly united (style confluent almost to apex and then curved outwards into 5 splits), stigma small, lavender. Capsule broadly oval-shaped or oval-shaped and conical, 10-14 mm long and 6-10 mm wide, light green, dark brown when ripe.

Phenology.

Flowering from April to June; fruiting from June to September.

Distribution and ecology.

This species is known to be found only in Libo County, Guizhou Province, China, on the top of a mountain in a karst landscape, alt. 947 m.

Etymology.

The species name “liboense” refers to the origin of the type specimen, Libo County, Guizhou Province.

Conservation status.

In the 2022-2023 period, we sampled the H. liboense population and found two more sites around the location where the species was first discovered, each with a population of approximately 20 plants. The habitat of H. liboense is mainly from the exposed rock gully area above the middle of the mountain to the top of the mountain. The soil in the plant habitat is poor, the soil layer is weak in its ability to retain water, and drought is common. At present, H. liboense is not known to be distributed in the low-altitude areas below the foot of the mountain and the middle of the mountain, so we hypothesize that the current availability of habitat for H. liboense is relatively poor and the population is relatively endangered. However, because our current investigation of the survival status and threat factors of H. liboense is not sufficiently comprehensive to provide information on the specific distribution of this population, we recommend that H. liboense be classified as "data missing" ( IUCN 2017).

Figures

Figure 2. Hypericum liboense A habitat B flower (a) undulating leaf margins C flower anatomy (a) petal (b) stamens (c) pistil (d) calyx (e) anther (f) gland D H. liboense branch with flowers E stylus F veins and glandular points of calyx G leaf blade half-clasping twig H abaxial side of calyx I blade J veins and glands K anatomy of fructus (a) whole fructus (b) longitudinal section of fructus (c) cross-section of fructus