Ilex calcicola W. B. Liao & Ke Wang Xu, 2017

Ilex calcicola W. B. Liao & Ke Wang Xu View in CoL , sp. nov. ( Figs. 2–4 View FIGURE 2 View FIGURE 3 View FIGURE 4 )

Diagnosis: — Ilex calcicola is similar to I. mamillata C. Y. Wu ex C. J. Tseng (1984: 413) and I. wuana T. R. Dudley (1988: 14), but differs from I. calcicola in having (1–) 5–8 (–10)- fruits per fascicle, the 6-merous flowers, the shape and size of leaves and the puberulent surface of leaves ( Table 1 View TABLE 1 ).

Type: — China. Guangxi: Baise City, Tianyang County, Tianan Village , growing in evergreen broadleaved forests in valley of limestone hills, 264 m, 23°34.709′N, 106°41.817′E, 14 April 2016, K. W. Xu and P. Yang XKW287 (holotype: SYS! GoogleMaps isotypes: SYS! GoogleMaps GXMI! GoogleMaps ).

Shrubs or trees evergreen, 10 m tall. Bark pale grey. Current year’s branchlets green, slender, puberulent, with gray rounded or elliptic lenticels; second year’s branchlets gray, subterete, with dense brownish lenticels. Terminal buds densely puberulent, conic. Petiole 5–11 mm, ca. 1 mm in diameter, puberulent, abaxially rugose, adaxially narrowly sulcate. Leaves persist one–three years on branchlets. Leaf blade narrowly elliptic, elliptic, or obovate-elliptic, rarely obovate, (3.5–) 5.2–8.5 (–11.5) ×(1.0–) 1.7–3.5 (–3.8) cm, leathery, pubescent abaxially, inconspicuously and minutely glandular punctate, midvein adaxially impressed, minutely pubescent, abaxially keeled, densely puberulent, with 5–10 pairs of lateral veins, obscure adaxially, conspicuously elevated abaxially, and reticulate veins obscure adaxially, obvious abaxially; leaf base cuneate or subrounded; leaf margin entire, apex acuminate, rarely acute. Male inflorescences: cymes (1–) 3–6-flowered, fasciculate, axillary on current year’s branchlets or on leaf scars of second or third year’s; peduncles (1–) 2–4 mm; pedicels (1.5–) 4–8 mm, densely puberulent; bracteoles basal, deltoid, puberulent; flowers 6-merous; calyx patelliform, 6-lobed, lobes deltoid-ovate, ca. 0.6 mm long, ca. 0.8 mm wide at base, papery, puberulent, ciliate; petals 6, white, broadly oblong, ca. 3 mm long, basally slightly connate; stamens ca. as long as petals; rudimentary ovary ovoid. Female inflorescence: cyme 1(–2)-flowered, fasciculate, rarely solitary; bracts triangular, ciliate; pedicels 4–7 mm long, densely puberulent, with 2 lanceolate ciliate sub-basal bracteoles (prophylls); calyx and corolla as in the staminate flowers; staminodes slightly shorter than petals; sterile anthers triangular, ca. 0.6 mm long, ca. 0.4 mm wide at base; ovary ovoid, ca. 2.5 mm in diameter; persistent stigma mammilliform, cylindric. Infructescences: 1- fruited cymes (rarely 2-fruited cymes), fasciculate, fascicles (1–) 5–8 (–10)-fruited, axillary; fruiting pedicels 3–6 mm, puberulent; persistent bracteoles basal, deltoid, puberulent. Fruit red, globose, ca. 4 mm in diameter; persistent calyx 6-lobed, lobes broadly deltoid, puberulent, ciliate; persistent stigma mammilliform or cylindric; pyrenes 6, ellipsoidal, ca. 3 mm long, ca. 1 mm in diameter, abaxially longitudinally 3-striate and 2-sulcate, laterally 4-striate and 3-sulcate, endocarp leathery.

Pollen and stomata morphology:— The pollen grains of I. calcicola are tricolpate. Polar axis (P) is ca. 23.08 μm, equatorial axils (E) is ca. 10.83 μm. The exine is ornamented with conspicuous gemmae and clavae of variable size ( Fig. 4A, 4B, 4C View FIGURE 4 ). The stomatal type ( Fig. 4D, 4E View FIGURE 4 ) of this new species is amphicyclocytic, which is the most common and basic type of Ilex ( Li et al. 2010) . The mean density of stomata is ca. 0.05 per 1 μm 2 ( Fig. 3D View FIGURE 3 ). The mean size of the normal stomata is 26.32×22.63 μm. The hairs of the new species ( Fig. 4F View FIGURE 4 ) is short and soft.

Phenology:— Flowering November–May and fruiting March–July.

Distribution, habitats and population:— Ilex calcicola is currently known only from the type locality in Tianan village, Tianyang County, Baise City, western Guangxi, China. The new species occurs in evergreen broadleaved forests in valley at altitudes of ca. 200–350 m a.s.l. of limestone hills. During our investigations, only one population of I. calcicola was found with no more than 100 mature individuals in the type locality and nearby.

IUCN Red List category:— The only population is found from the type locality and comprised about 100 mature individuals. The status of the new species clearly should be‘Critically Endangered’(CR) based on current information and following IUCN (the International Union for Conservation of Nature and Natural Resources) guidelines ( IUCN 2015).

Etymology:— From the Latin calcicola, referring the limestone habitat of the new species.

Additional specimens examined (paratypes):— China. Guangxi: Baise City, Tianyang County, Tianan Villiage , 23°34.709′N, 106°41.817′E, elev. 210 m, 4 May 2017, K. W. Xu & J. J. Wang XKW288, female, fl. ( SYS!) GoogleMaps ; the same locality, elev. 225 m, 4 May 2017, K. W. Xu & J. J. Wang XKW325, male, fl. ( SYS!) GoogleMaps .