Fordiophyton tereticaule S.Jin Zeng & N.H.Xia, 2022

Zeng, Si-Jin, Tong, Yi-Hua & Xia, Nian-He, 2022, Fordiophyton tereticaule (Melastomataceae), a new species from China, PhytoKeys 197, pp. 59-69 : 59

Fordiophyton tereticaule S.Jin Zeng & N.H.Xia sp. nov.

Figs 2 , 3 Verbatim name: 圆茎异药花

Type.

China. Yunnan: Wenshan Zhuang and Miao Autonomous Prefecture , Malipo County, Laojunshan Provincial Nature Reserve , elev. 1517 m, 18 September 2020 (fl.), Si-Jin Zeng 4932 (holotype: IBSC!; isotypes: CANT!, KUN!, PE!) .

Diagnosis.

Similar to F. faberi in having erect stems, membranous leaf blades, and oblong petals, but differs by the terete (vs. quadrangular) stems, densely puberulous (vs. green and glabrous or shortly setose near leaf blade base) petioles, and elliptic (vs. broadly lanceolate, oblong, ovate, or rarely lanceolate) leaf blades.

Description.

Herbs, 30-100 cm tall. Stems yellowish-green when young, turning red, terete, with dense glandular trichomes and puberulous when young, becoming glabrescent, inflated at the nodes. Leaves in unequal pairs in size; petiole reddish brown, terete, 1-7 cm long, densely puberulous; leaf blade elliptic, slightly oblique, 8-16 × 4-9 cm, membranous, base cordate, apex acuminate to caudate-acuminate, margin inconspicuously serrulate with each tooth bearing a terminal seta, adaxial surface yellowish-green, sparsely puberulous, abaxial surface yellowish-green, densely puberulous on veins; secondary veins 2-3 on each side of midvein, conspicuous; tertiary veins numerous, parallel, connecting with secondary veins. Inflorescences terminal, an umbel-like cyme, sometimes a thyrse, with 6-15 flowers; peduncle usually dull red, terete, 1.3-3.5 cm long, with dense red glandular trichomes; bracts yellowish-green to dull red, imbricate at base of pedicel, broadly ovate to suborbicular, with sparse red glandular trichomes, caducous. Pedicel dull red, terete, 3-5 mm long, with dense red glandular trichomes. Hypanthium scarlet, funnel-form, 6-8 × 3-4 mm, with dense red glandular trichomes. Calyx lobes dull red to scarlet, triangular to ovate-triangular, ca. 5 × 2-4 mm, with sparse red glandular trichomes, apex obtuse to acute, base not auriculate. Petals white to pinkish, oblong, ca. 1.1 × 0.5-0.6 cm, apex oblique with 1 glandular trichome at tip. Stamens 8, 4 longer antisepalous ones and 4 shorter antipetalous ones, arranged in 2 whorls. Antisepalous (longer) stamens 2.0-2.5 cm long; filaments 0.9-1.4 cm; anthers dull red, linear, ca. 1.1 cm long, curved, base lengthened into a forked, curved spur, connective base inflated. Antipetalous (shorter) stamens 0.9-1.2 cm long; filaments 0.6-0.9 cm; anthers yellow, ovoid, ca. 0.3 cm long, straight, connective base slightly inflated. Style 1.7-2.0 cm long, glabrous or with sparse glandular trichomes at base. Ovary half-inferior, ovoid, apex with a membranous crown. Capsule funnel-form, ca. 8 × 4 mm; placentation axillary, placentas shortly stalked; seeds more than 100, cuneate, less than 2 mm long.

Phenology.

Flowering in September-December, fruiting in October-next January.

Distribution and habitat.

Fordiophyton tereticaule is only known from Malipo County, Yunnan, China. It grows in broad-leaved evergreen forests at elevations of 1260-1540 m.

Etymology.

The specific epithet refers to the terete stem.

Additional specimen examined.

China. Yunnan: the same locality as above, 1516 m, 28 November 2019, Si-Jin Zeng 898 (paratypes: IBSC!).

Figures

Figure 2. Fordiophyton tereticaule S. Jin Zeng & N. H. Xia A fruiting branch B part of stem with one petiole C part of leaf blade, adaxial view D cymose inflorescence with opening flowers E calyx lobe F petal G longer stamen, front view (left) and side view (right) H shorter stamen, front view (left) and back view (right). Drawn by Ding-Han Cui.

Figure 3. Fordiophyton tereticaule S. Jin Zeng & N. H. Xia A flowering plants B part of stem with a pair of petioles C a pair of leaves D cymose inflorescence with flower buds E cymose inflorescence, oblique view F an opening flower, front view G an opening flower, side view H infructescence, side view I young fruits, top view.