Viola rheophila Okamoto

Wang, Zheng-Wei, Wu, Zhi-Jin, Wang, Qi, Li, Yi-Fan, Yuan, Lang-Xing & Li, Xiao-Chen, 2024, Morphological and Phylogenetic Analysis Reveals Two New National Records of Viola (Violaceae) from Southwestern China, Phytotaxa 666 (2), pp. 93-106 : 96-99

Viola rheophila Okamoto Dz ṅ堇= ( Figs. 4 , 5C , 6 , 8 , 9B )

Bull. Osaka Mus. Nat. Hist. 37: 10 (1984); Acta Phytotax. Geobot. 38: 121. Fig. 11 (1987); Flora of Thailand. Vol 14. Part 1: 180 (2018).

TYPE. Indonesia, Kalimantan Timur, Krayan County, bank of river Pa Raya, between Pa Raya and Sinar Baru, North of Long Bawan , 1150m, 17 July 1981, Kato, Okamoto & Walujo B-9020, KYO 00106578 (Holotype: KYO!) ; along the river Tadur Bangar, a branch of Pa Raya , ca. 1200 alt. 23 July 1981, Kato et al. B-9683, KYO 00106579 (Paratype: KYO!) .

Description: Herb perennial, rhizome stout, erect or oblique, nodes densely spaced, usually coverd by persistent stipules and leaves, with slender stolons up to 30 cm long that root well at the nodes. Stipules linear-lanceolate, margin sparsely fimbriae, dark in color. Leaf blade ovate-lanceolate, 12–45 × 6–23 mm, base rounded or truncate-cuneate, decurent to petiole, margins sparsely serrated, apex acute, glabrous, green adaxially and bluish-green abaxially. Peduncles erect, bracts 2, above the middle, nearly opposite, margin sparsely dentated or entire. Sepals 5, linear-lanceolate, upper 3 ones larger, 5–7 × 1 mm, basal appendage about 0.5 mm, apex rounded or toothed. Petals 5, white, upper two ones are oblanceolate, reflexed, 8–12 × 2.5–4 mm, base of the lateral two ones glabrous, anterior one obovate, white with purple veins, extending downward into a short spur, saccate, ca. 2 mm. Stamens 5, lowest two ones equiped with a curved strip-shaped appenda projecting into the spur respectively. Style kneed at the base, club-shaped, and faintly lobed on the sides at the tip. Capsules are ellipsoid, seed small, about 0.7 × 0.5 mm, without distinck elaiosome. Seed small, ellipsoid, without distinct elaiosome. Flower and fruit were observed irregular year round under cultivation.

Ditribution: Indonesia, Thailand, Vietnam, new record of China, Yunnan Province, Wenshan Zhuang and Miao Autonomous Prefecture, Malipo County, Tianbao Town , 1515m, 23.0418° N, 104.8048° E, 27 Jan 2024, in flower, Li Yi-fan, LYF20240127 ( CSH) ; Guangxi Zhuang Autonomous Region, Baise City, Napo County, Baisheng Township, Nongmiao Village , 16 Jun 2024, in fruit, Yuan Lang-xing, YLX20240622 ( CSH) .

Other digital specimens examinated: Indonesia, East Kalimantan, Krayan, Long Bawan , between Pa Raya and Pak Rusugang, elevation 900 m, rheophyte, on bank, 17 Sep. 1990, M. Kato et al., 23451 (L4265629); along Pa Pani River, 26 Sep. 1990, H. okada et al. 25238 (NMNH03020441). Thailand, NE Loei province, mt. Phu Kradueng, 1 Nov 1984, 101°47-49’ E, 16°53-54’ N, along trail to water fall by stream, 1150–1250m, Gen Murata et al. , T-42582 (L2446329). Vietnam, Tinh Ha Giang, 9 Oct. 2019, 23° 2′ 6.47″N, 104° 52′ 12.58″ E, steep rocky mountain slopes composed of eroded limestone at elevation 1100–1250 m, Averyanov Leonid Vladimirovich et al., VR1488 (LE01066945); Tinh Ha Giang, 18 Apr. 2018, 23° 7′ 46.4″ N, 104° 57′ 56.2″ E, on mossy rocks on mountain top, at elevation 1000-1190 m, Averyanov Leonid Vladimirovich et al., VR336 (LE01067086). More living plant photos of V. rheophila were deposited at China Field Herbarium (https://www.cfh.ac.cn/album/ShowSpAlbum.aspx?spid=7030780).

Figures

FIGURE 4. V. rheophila from Yunnan (A) and Guangxi (B) and the type specimens (C & D).

FIGURE 5. Habitat of V. annamensis (A & B) and V. rheophila (C) from field in China. A & B were taken by Wang Zheng-wei and Wu Zhi-jin based on collection of WZJ00833, C were taken by Li Yi-fan based on collecton of LYF20240127.

FIGURE 6. Distribution of V. annamensis and V. rheophila in China.

FIGURE 8. Flower of V. rheophila. A: Style and spurred stamens. B: Petals. C: Bracts, sepals and spur of anterior petals. D: Ovary and style. Photos based on living collection of LYF20240127.

FIGURE 9. Leaf blade of V. annamensis (A1-A4, A1 & A2 show the two faces of the same leaf) and V. rheophila (B1-B4, B1 & B2 show the two faces of the same leaf). A1-A4 were based on living collection of WZJ00833, B1-B4 were based on living collection of LYF20240127.

FIGURE 11. Type specimen of V. hossei W. Becker. Downloaded from GBIF.