Didymocarpus brevipedunculatus Y.H.Tan & Bin Yang, 2019

Yang, Bin, Ding, Hong-Bo, Fu, Kai-Cong, Yuan, Yi-Kai, Yang, Han-Yu, Li, Jian-Wu, Zhang, Li-Xia & Tan, Yun-Hong, 2019, Four new species of Gesneriaceae from Yunnan, Southwest China, PhytoKeys 130, pp. 183-203 : 183

3. Didymocarpus brevipedunculatus Y.H.Tan & Bin Yang sp. nov. Figures 5 , 6

Diagnosis.

Didymocarpus brevipedunculatus is similar to D. purpureobracteatus in bracts ovate to orbicular and calyx tubular, but it can be easily distinguished from the latter by its leaf base extremely obliquely cordate (vs. leaf base sometimes oblique, cuneate to cordate), inflorescence gracile, pendulous (vs. erect), inflorescence much shorter than leaf (vs. inflorescence much longer than leaf), peduncles (4.0-5.5 cm vs 4.0-10 cm long), flowers white with purplish to deep red longitudinal stripes (vs. purple to pinkish purple with darker stripes), and peduncles villous with eglandular, multicelluar hairs (vs. glabrous).

Type.

CHINA. Yunnan: Ximeng, Mengsuo, grows on rock surfaces along a seasonal waterfall or moist and shade places in evergreen forest, 22°38'04.83"N, 99°35'34.17"E, a.s.l. 1200 m, 8 September 2012, Yun-Hong Tan 6930 (holotype: HITBC! Isotype: HITBC!).

Description.

Deciduous, perennial, epilithic herb, 30-40 cm tall, stem 4-6 mm in diameter. Dry season juvenile leaves distinct, blades symmetrically ovate, c. 1.5 × 1 cm, with much denser indumentum than when mature. Rainy season stems succulent, erect, green, densely and finely villous with multicellular eglandular hairs; pigment glands absent. Leaves 4-6 arranged in opposite, decussate, anisophyllous pairs; blades asymmetrically ovate, thin, papery when dry, upper surface dull dark green and drying medium brown, densely villous with eglandular, multicellular hairs, lower side pale light green and drying light brown, densely villous with eglandular, multicellular hairs along veins, 10-25 cm long, 6.5-15.5 cm wide, apex attenuate to acuminate, base extremely obliquely cordate, margins serrate, often irregularly so, or doubly serrate, midrib with 9-11 arching secondary veins on each side, distinct on both surfaces, finer venation reticulate; petioles 4.5-12.0 cm long, with indumentum as on the stems. Inflorescence solitary per axil, cymose, gracile, pendulous, 7-12 cm long, villous with eglandular, multicellular hairs, laxly cymose, axes succulent, light green to green; Peduncles 4.0-5.5 cm long, densely villous with eglandular, multicellular hairs; Hypopodium 1.0-2.0 cm long, glabrous or sparsely villous; Pedicels 3-5 mm long, glabrous or sparsely villous. Bracts paired; green to light green, sparsely villous with eglandular, multicellular hairs, orbicular to ovate, 5.5-6.0 mm long and wide. Bracteoles paired, whitish to light green, glabrous or sparsely villous, orbicular to ovate, 4.0-5.5 mm long and wide. Flowers numerous. Calyx campanulate, glabrous, often light green on both side, sometimes purplish outside; tube c. 6 mm long; lobes ovate, subequal to equal, 5(6) lobed, apices obtuse to rounded; 0.5-1.0 mm long. Corolla funnelform, 4.0-4.5 cm long, glabrous, white, inside with 9 purplish to deep red longitudinal stripes, 3 per lobe in the lower lip; tube 3.2-3.5 cm long, gradually widening from the base to the throat, 0.8-1.0 cm wide at base, 1.8-2.0 cm at throat; lobes ovate to suborbicular, broadly rounded; anterior (lower or abaxial) lip 3-lobed, 6-7 mm long, 7-8 mm wide apices rounded, posterior (upper or adaxial) lip 2-lobed 5-6 mm long, 7-8 mm wide, apices rounded. Fertile stamens 2, inserted at c. 2 cm above the base of the corolla; filaments 0.9-1.0 cm long, glabrous; anther locules oblong, c. 2 × 1 mm, tips and bases rounded, white-bearded, cream; Staminodes 3, inserted slightly below the stamens, lateral ones 5 mm long, the other one 3 mm long, glabrous. Disc ring-like, thickened, glabrous, margin entire or slightly lobed, 2-3 mm high, persistent in fruit. Ovary cylindric, slightly stipitate, glabrous, light green, c. 2.5-3.0 cm long, 1 mm wide; style continuous with the top of the ovary, c. 5 mm long, glabrous, whitish or light green; stigma discoid, concave medially, whitish, 1 mm diameter. Capsules cylindric, slightly stipitate, erect, straight, light green, when maturing light brown, 4.5-5 cm long and 2.5 mm wide. Seeds, numerous, elliptic, appendage absent, cell ornamentation straight, cell faces finely verrucate.

Etymology.

The new species is named after its axillary relatively short peduncles.

Vernacular.

Chinese mandarin: Duan Xu Chang Shuo Ju Tai (短序长蒴苣苔)

Phenology.

Flowering August-September and fruiting September-October.

Distribution and habitat.

The new species was found in south Yunnan, Ximeng and Cangyuan Counties. It grows on rock surfaces along a seasonal waterfall or in moist and shady places in evergreen forests, altitude 1000-1200 m.

Conservation status.

The localities of this new species, in Ximeng and Cangyuan, are both part of protected areas, and a total of more than one hundred individuals were found in the wild; a further inventory is needed to clarify the habitats and populations. At present, the species is therefore assigned a preliminary status of Endangered (EN D) according to the IUCN Red List Categories and Criteria ( IUCN 2012).

Note.

A comparative list of diagnostic characters of the new species and D. purpureobracteatus is given in Table 3 .

Figures

Figure 5. Didymocarpus brevipedunculatus Y. H. Tan & Bin Yang, sp. nov. A, B Habit C, D inflorescence E flowers F young capsules G dissected calyx H dissected corolla I bracts J bracteoles. Photographed by Y. H. Tan.

Figure 6. Didymocarpus brevipedunculatus Y. H. Tan, sp. nov. A Habit B leaf base in abaxial view C inflorescence D bract in abaxial view E bracteole F flower in front view G dissected corolla H stamens I young capsule J calyx K pistil L stigma. Drawn by Yun-xi Zhu.