Viola hybanthoides W. B. Liao et Q. Fan, 2015

Fan, Qiang, Chen, Sufang, Wang, Longyuan, Chen, Zaixiong & Liao, Wenbo, 2015, A new species and new section of Viola (Violaceae) from Guangdong, China, Phytotaxa 197 (1), pp. 15-26 : 20

Viola hybanthoides W. B. Liao et Q. Fan , sp. nov. ( Fig. 5 , 6 )

Species Violae tricolori Linn. similis, sed subfruticibus, floribus minoribus, 8–11 mm diam., petalis inferioribus unguibus, stigmatibus leviter bifidis differt.

TYPE:— CHINA. Guangdong: Renhua County, Mt. Danxia , on the top of a small hill, 197 m, 25°01′05.92″N, 113°44′41.23″E, 23 May 2012, Q. Fan 11605 (holotype SYS!, barcoding number 190591; isotype IBSC!) .

Subshrubs, perennial, without basal leaves. Rhizomes erect, rather stout, sometimes absent. Stems erect or somewhat ascending, much-branched, 20–45 cm tall, glabrous. Leaves alternate; stipules leaflike, free, glabrous, oblonglanceolate, 5–9 × 1–2 mm acuminate, fimbriate; petioles glabrous, 0.6–2.1 cm long, narrowly decurrent-alate; blades elliptic or ovate-lanceolate, 1.8–2.8 × 0.8–1.4 cm, thinly chartaceous or membranous, glabrous, densely dotlike brown glandular on both sides, 2 to 3 veins on each side of midrib, margin coarsely serrate, base cuneate-decurrent. Flowers 8–11 mm diam; pedicels slender, 1.6–4.2 cm long, exceeding leaves, glabrous, with two opposite bracteoles above middle or near flower; bracteoles glabrous, linear, 1.5–2.2 × 0.3–0.6 mm, margin scarious, apex acuminate. Sepals green, glabrous, linear-lanceolate, 2.7–3.7 × 0.5–1 mm, margin entire, apex acuminate, base truncate or rounded, sepal appendages very short, c. 0.3 mm long. Petals whitish to pale purple, with apparent violet lines, anterior one with a green patch at base, glabrous; upper petals, oblong to linear-lanceolate, 2.5–3 × 0.5–0.8 mm, margin erose basally, apex obtuse or erose; lateral petals, oblong, 4.5–5 × c. 1.5 mm, margin erose basally, apex obtuse or erose; anterior petal with a long claw and a short saccate spur at base, broadly spathulate or flabellate, margin slightly undulate, blade 5–6 × 7–8 mm, claw 3–3.5 mm long (spur included), margin reflexed, apex rounded, truncate or emarginate, spur straight and saccate, very short, c. 1.5 mm, apex obtuse. Stamens 5, unequal, with very short filaments, the anther thecae c. 0.6 mm long, terminal appendages c. 0.5 mm long, the posterior appendages (nectar spurs) of two anterior stamens 0.7–1 mm long. Ovary ovoid to ellipsoid, c. 0.8 mm diam., glabrous; style c. 0.8 mm long, conspicuous geniculate at base; stigma capitate, slightly 2-lobed, not beaked in front, with a stigmatic hole between the lobes and with a membranaceous lamellar processus below the hole. Capsule brownish at maturity, ovoid, 3–4 mm long. Seeds brown, ovoid, 1.2–1.5 mm long.

Phenology:—Flowers from March to July and fruits from April to August (observation by Zaixiong Chen in the field from March, 2012 to December, 2013).

Distribution and Habitat:— Viola hybanthoides is currently known only from two localities in on Mt. Danxia, Renhua County, northern Guangdong, China. The species grows in sunny thickets on dry red-colored sandy soil at the top of a small hill and on a steep slope near the summit. The associated species include Osteomeles subrotunda , Firmiana danxiaensis , Lagerstroemia indica , Rhamnus brachypoda and Pinus massoniana .

Conservation Status:—Only two populations were found with no more than 1000 mature individuals in an total area of about 1 km 2. It’s about 10 km away between the two populations. Thus the species could be considered as CR (Critically Endangered) status according to IUCN Red List criteria (B2a; IUCN 2001).

Etymology:—The anterior petal with a long stalk-like claw and the inconspicuous upper petals of the new species are very similar to those of some Hybanthus species, therefore we used the specific epithet “ hybanthoides ”.

Paratype: CHINA. Guangdong: Renhua County, Bazai in Mt. Danxia, on the sunny slope, 400 m, 25°00′29.03″N, 113°39′41.82″E, 26 April 2013, Z. X. Chen 401 (SYS).

Figures

FIGURE 5. Viola hybanthoides W. B. Liao et Q. Fan. A. Habit and flowering branch. B. Leaf and stipules. C. Flower, lateral view. D. Flower, front view. E. Petals. F. Ventral stamen in adaxial (right) and abaxial (left) view. G. Posterior stamen in adaxial (right) and abaxial (left) view. H. Pistil. I. Young capsule with sepals and bracteoles. J. Dehiscent capsule and seeds. Drawn by Yunxiao Liu from the holotype.

FIGURE 6. Viola hybanthoides W. B. Liao et Q. Fan. A. Habitat. B. Habit. C. Stem with stipules. D. Flower, front view. E. Flower, lateral view. F. Young capsule with sepals and bracteoles. G. Dehiscent capsule and seeds. Photos taken by Sufang Chen.