Rohdea chloroxantha H. Z. Feng 2023, sp. nov.
Creators: name: Feng, Hui Zhe
name: Zhao, Yan Ying
name: Bi, Ming Hui
name: Li, Wen Hui
name: Chang, Ce
name: Yuan, Juan Juan
name: Chen, Jing
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Liliopsida
Asparagales
Asparagaceae
Rohdea
Rohdea chloroxantha

description: Rohdea chloroxantha H.Z. Feng, sp. nov. (Figs. 1 A–H, 2, 3 C)
Type:— CHINA. Shannxi Province: Zhenba County, Dachi Town, alt. ca. 1850 m, 3 October 2022; herbarium specimen prepared from the plant cultivated in garden in Zaozhuang University on 27 April 2023, Feng 2023–04104 (holotype, CSH!).
Diagnosis:— Rohdea chloroxantha most closely resembles R. pachynema in having long stolons, but differs by the chartreuse flowers; the perianth thick fleshy, the perianth tube semi enclosed with fleshy appendages at orifice, lobe margin semi-transparent; appendage and stamens constituted a semi-closed small space, and wrap the pistil inside filaments cylindrical and the base reniform in cross section.
Description:—Chamaephytic herb. Rhizome cylindrical, up to 3.5 cm in diameter, producing long slender subterranean stolons to more than 40 cm, ca. 3 mm in diameter. Roots fibrous, to 3 mm in diameter. Leaves 6–8, basal, distichous equitant; petiole ca. 3 cm, usually conduplicate; leaf blade linear-lanceolate to oblanceolate, 20–35 × 2.5–5 cm broad. Cataphylls a few. Peduncle 3.5–5 cm long. Spike densely many-flowered, ca. 4 cm long, ca. 2 cm in diameter, with marked terminal tuft of sterile bracts, ca. 1 cm long. Bracts 2 per flower; outer bract 1, borne below flower, triangle, cuspidate-acuminate, more or less low than flower, to 8 mm long, 5 mm broad; inner bract (bracteole) 1, smaller, narrowly lanceolate. Perianth campanulate, chartreuse, ca. 10 mm across; lobe deltoid-lanceolate, ca. 3 mm long, 4 mm broad, thick fleshy, apex cuspidate-acuminate, thinner at margin, semi-transparent, imbricate below; tube ca. 5 mm long, with thick fleshy annulus appendages at orifice. Anthers orbicular-elliptic, ovate or broadly ovate, ca. 1 mm long; free part of filaments incurved, ca. 2.5 mm long, inserted subdistally on perianth tube; the base of filaments united with the fleshy appendages and the base of filaments reniform in cross section. The appendage and stamens constituted a semi-closed small space, ca. 6 × 7 mm and wrap the pistil inside. Pistil 2.0– 3.5 mm long; stigma trisected, lower than the base of filament; style columnar, 1–1.5 mm long; ovary slightly depressed globose, 2–2.5 mm long.
Phenology:—Flowers in April.
Etymology:—The specific epithet is derived from its chartreuse flowers.
Distribution:— Rohdea chloroxantha is from Zhenba County, south Shaanxi, China. It grows on shady and moist places in forests or slopes along stream sides at elevations of 1850 m a.s.l. According to specimen records in 2011, this species is also distributed in Wangcang County, northeast Sichuan, China, but we did not investigate this area. Both Zhenba and Wangcang Counties belong to the Daba Mountains in a broad sense. Zhenba County is on the north slope, and Wangcang County is on the south slope.
Conservation status:— Rohdea chloroxantha is currently known from Zhenba in south Shaanxi, China. Only approximately 150 mature individuals were discovered. They are scattered within ca. 0.5 km along a valley. The activity of collecting traditional Chinese medicine in particular, may destroy their habitats and, thus, severely affect the survival of this species. According to the IUCN Red List Categories and Criteria (IUCN 2012), R. chloroxantha may better be categorised as Endangered (EN).
Notes:—Undoubtedly, the long slender subterranean stolons and similar vegetative reproduction suggest that the new species is closely related to R. pachynema and R. grandiflora. Rohdea grandiflora was described on the basis of one collection, Feng 2022 –0317 (holotype, CSH0197017!), Kang County, Longnan City, Gansu Province, China. In addition to having the stolons, the blades edges of the new species and R. grandiflora with serrated but they can be distinguished by the flower structure of latter is relatively uncomplicated which the perianth tube smooth and without appendages, filaments inserted at the lobes and the diameter of the flower is more than 2 cm (Fig. 3 D).
Campylandra pachynema was described on the basis of a single collection, P.S. Ten 4007 (holotype, PE00034630!), route from Loupou to Kiaokia (Qiaojia County), Yunnan, China. C. pachynema resembles R. fargesii (Baillon 1893: 1114) var. fargesii Y.F. Deng (2017: 298), as Wang & Tang (1978), Huang et Li (1990), Yang (in Xu 1991) and Liang & Tamura (2000) treated them as conspecific. Tanaka (2010) transferred C. pachynema to Rohdea as R. pachynema as one independent specific status, based on these two species differs by the rhizome producing long slender subterranean stolons, coriaceous leaves, prominently incrassate perianth often with broad lobes, and deltoid or prominently dilated filaments inserted slightly below the orifice of the perianth tube. In R. chloroxantha the perianth tube with fleshy annulus appendages at orifice and the filament base not expand in triangular which can be easily distinguished from R. pachynema (Fig. 3 A C).
Based on Tanaka (2010), R. pachynema appears to have descended from the ancestral lineage of R. fargesii var. fargesii. Obviously, R. chloroxantha and R. fargesii var. fargesii also have a relatively close relationship. In many populations of R. fargesii var. fargesii, the filaments decurrent parts on tube usually dilated and united with adjacent ones, forming small protuberance at each junction (Fig. 3 B). In R. chloroxantha, we also found some protuberance (annulus appendages) between adjacent filaments, but great than in R. fargesii var. fargesii. This appendage connate with the filaments, and the connate site is reniform in cross section. The appendages between adjacent filaments in R. fargesii var. fargesii had been thought to result from the filaments dilated (Wang & Tang 1978, Tanaka 2010). But, in R. chloroxantha the annulus appendages should be produced by the protrusion of the inner wall of the perianth (Fig. 2 I). And in the new species, the appendage and stamens constituted a semi-closed small space to wrap the pistil inside, which is very different from the open perianth tube of R. fargesii var. fargesii, R. pachynema and R. grandiflora (Fig. 3).
Other specimens examined:— Rohdea chloroxantha, CHINA, Sichuan, Wangchang, Bashan Exped. 4887 (PE01872791). Rohdea grandiflora, CHINA, Gansu, Kangxian, Y.Q. He & C.L. Tang 331 (WUK214839); Wudu, Z.Y. Zhang 1961 (WUK160880); Zhouqu, Bailongjiang Exped. 681 (PE01537175), Bailongjiang Exped. 4442 (PE01823458). Sichuan, Pingwu, L. Zhang, T. Wan & H. Wang 293 (PE01994175).
Rohdea pachynema, CHINA, Sichuan. Butuo, Anonymous 25192 (SM722208193); Ganluo, Liangshan Wild Plant Expend. Chuanjingliang- 4379 (CDBI0166793); Jiulong, Anonymous 0316 (SM722208175); Luding, X.M. Gao G06011 (WCSBG006383), G.H. Xu 25379 (CDBI0166770), Q.Q. Wang & Z.A. Liu 21992 (CDBI0166762), Flora Exped. 25025 (CDBI0166763); Puge, Anonymous 5518 (PE00593107); Shimian, Shimian Exped. 78-1018 (SM722208174); Xichang, Y.J. Li 595 (CDBI0166766), J.P. Zhang 567 (CDBI0166764); Yanbian, Yanbian Exped. 0126 (SM722208191); Yuexi, Anonymous 0109 (SM722208187); Zaojue, S.X. Chen 81026 (CDCM0003407), Vegetation Survey Group 32176 (CDBI0166767). Yunna, Luquan, P.Y. Mao 01885 (PE00593070); Qiaojia, Z.X. Ren, W. Jiang & M.Y. Zhang WH-2012-0419 (KUN1391649).
description: Published as part of Feng, Hui Zhe, Zhao, Yan Ying, Bi, Ming Hui, Li, Wen Hui, Chang, Ce, Yuan, Juan Juan & Chen, Jing, 2023, Rohdea chloroxantha (Asparagaceae), a new species from Southern Shaanxi, China, pp. 255-260 in Phytotaxa 607 (4) on pages 256-259, DOI: 10.11646/phytotaxa.607.4.4, http://zenodo.org/record/8243355