Senecio boluangensis Koyama (1988: 156)

Tong, Tian-Jing, Ren, Chen & Yang, Qin-Er, 2018, The identity of Senecio obtusatus (Asteraceae, Senecioneae) and a previous misapplication of the name, Phytotaxa 351 (2), pp. 154-162 : 155-159

2. Senecio boluangensis Koyama (1988: 156) . Figs. 1D (the left individual only), 2, 7.

Type:— THAILAND. Chiang Mai: along road from Bo Luang to Omkoi, Boluang Tableland, April 1968, 21 May 1942, C. F. van Beusekom & C. Phengkhlai 1147 (holotype BKF 014027!, isotypes C 10007874!, K 000852207!, L 0002264!). Fig. 7 .

Senecio obtusatus auct. non Wallich ex Candolle: Clarke (1876), Hooker (1881), Franchet (1896), Dunn (1911), Hu (1968), Jeffrey & Chen (1984), Koyama (1988), Chen & Liu (1989), Mathur (1995), Chen (1999), Kress et al. (2003), Liu (2004), Chen et al. (2011).

Herbs, perennial, subscapigerous, rhizomatous. Stems usually solitary, erect, 30–80 cm tall, slender, simple or branching into inflorescence, pubescent especially near base or more or less glabrous. Basal leaves present at anthesis, rosulate, shortly petiolate, winged, basally expanded but not auriculate; blade elliptic, 5–21 cm long, 2–5 cm broad, thickly papery, both surfaces sparsely pubescent to glabrous, pinnately veined, lateral veins 14–18, base cuneate or broadly attenuate into winged petiole, margin shallowly acutely sinuate-denticulate, apex acute; median stem leaves few, sessile, oblong to linear, base expanded and subamplexicaul, margin denticulate, apex obtuse; uppermost leaves linear, bractiform. Capitula radiate, few to many in terminal corymb or compound corymb, branches slender; peduncles 5–20 mm long, slender, sparsely pubescent, linear-bracteate, bearing 2–3 linear bracteoles. Involucres narrowly campanulate, 3–5.5 mm long, 2.5–6 mm broad, calyculate; bracts of calyculus 4–5, linear-subulate; phyllaries 10–13, oblong, 1 mm broad, herbaceous, sparsely puberulent abaxially, margin broadly scarious, apex acute, dark, shortly bearded. Rayflorets ca. 8; corolla tube 3 mm long; rays yellow, oblong or elliptic-oblong, 6.5 mm long, 2 mm broad, apically obtuse, 3-denticulate, 4-veined; disc-florets ca. 25; corolla yellow, 5.5 mm long, with 3 mm long tube and infundibuliform limb; lobes ovate-lanceolate, 1 mm long, apically acute, papillose. Anthers 1.6 mm long, basally distinctly subacutely auriculate, appendages ovate-lanceolate; antheropodia rather small, basally slightly dilated. Style branches 0.8 mm long. Achenes cylindrical, 4 mm long, pubescent. Pappus 5 mm long, white.

Line drawings: —Plate 61: 1–5 under the name Senecio obtusatus in the Flora Reipublicae Popularis Sinicae vol. 77 (1) ( Chen 1999); plate 456: 1–5 also under the name S. obtusatus in the Flora of China Illustrations vol. 20–21 ( Wu et al. 2013). The illustrations were most likely executed from the collection H.C. Wang 2172 (IBSC; Fig. 2D ).

Phenology: —Flowering in April–August, fruiting in May–September.

Distribution and habitat: — Senecio boluangensis is distributed in China (Guizhou, Sichuan, Yunnan), India and Thailand ( Fig. 5 ). It was also recorded, under the name S. obtusatus , to occur in Myanmar ( Jeffrey & Chen 1984, Koyama 1988, Chen 1999, Kress et al. 2003, Chen et al. 2011), but we have been unable to see any specimens from this country. This species grows on mountain slopes, at stream sides or forest margins at elevations of 1200–3350 m above sea level.

Additional specimens examined: — CHINA. Guizhou: Pingba, Pingba Exped. s.n. (KUN); Without locality, H.G. Esquirol 6681 (P). Sichuan: Huili, Woody Oily Plant Exped. 65-0230 (HIB, KUN); Mianning, Legendre 1363 (P); Miyi, S.Y. Chen et al. 10320 (SZ). Yunnan: Binchuan, J.M. Delavay s.n. (P); Dali, J.M. Delavay 2604 (P), G. Forrest 7251 (E); Heqing, G. Forrest 16482 (E); Jiangchuan, B.Y. Qiu 60369 (IBK, KUN); Lijiang, J.F. Rock 3719 (E), J.F. Rock 4437 (E); Mengzi, W. Hancock 526 (K); Schweli-Salwin divide, G. Forrest 24299 (E, PE); Songming, F. Ducloux 7485 (P), F. Ducloux 7556 (P), F. Ducloux 7594 (P), B.Y. Qiu 51705 (KUN, SZ); Tengyueh, G. Forrest 7528 (E, IBSC), G. Forrest 7580 (IBSC), G. Forrest 7635 (E), G. Forrest 7670 (E, PE), G. Forrest 12305 (E, PE), G. Forrest 26359 (E, IBSC, US), G. Forrest 29633 (E, PE); Yangbi, R.C. Ching 22287 (KUN, PE); Without locality, Lianda 10960 (KUN, PE).

INDIA. Khasia: C.B. Clarke 43339 ( US), J.D. Hooker & Thomson s.n. (K); Munipur: Vatt 6255 (P).

THAILAND. Loie: T. Smitinand 2468 ( US).

Notes: — Senecio boluangensis is very closely similar to S. spathiphyllus Franchet (1896: 416) in the subscapigerous habit and small, bractiform stem leaves in comparison with the oblong to oblanceolate basal leaves, but differs by having smaller involucres 3–5.5 mm (vs. 6–7 mm) long, 2.5–6 mm (vs. 3.5–4 mm) broad and shorter petioles (0–3 cm vs. 1–22 cm). From a morphological perspective, S. boluangensis is readily referable to S. ser. Subscaposi Jeffrey & Chen (1984: 400), in which S. spathiphyllus has been placed by the two authors.

Although Senecio boluangensis has not been included in any cytological and molecular systematic studies due to difficulty in obtaining material, we have checked the chromosomes of S. spathiphyllus and included it in our molecular phylogenetic analyses based on ITS, ETS, ndhF, psbA-trnH, 3’ trnK, 5’ trnK and trnL-F sequence data (Tong et al., unpublished). Our results indicate that S. spathiphyllus is a member of Senecio as redefined by Pelser et al. (2007).

Figures

FIGURE 1. Holotype and isotype sheets of Senecio obtusatus (= Jacobaea nudicaulis). A. Holotype (G-DC). B. Isotype (BM). C. Isotype (K). D. Isotype (K; only the right three individuals).

FIGURE 2. Specimens of Senecio boluangensis from China, previously all misidentified as S. obtusatus. A. Sichuan, Huili, Woody Oily Plant Exped. 65-0230 (KUN). B. Guizhou, Pingba, Pingba Exped. s.n. (KUN). C. Yunnan, Heqing, G. Forrest 16482 (E). D. Yunnan, Yangbi, H.C. Wang 2172 (IBSC).

FIGURE 5. Distribution of Senecio boluangensis (●) and Jacobaea nudicaulis (▲).

FIGURE 7. Holotype and isotype sheets of Senecio boluangensis. A. Holotype (BKF). B. Isotype (C). C. Isotype (L). D. Isotype (K).