Elatostema tiechangense L.F. Fu, Y.G. Wei & A.K. Monro, 2017
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publication ID |
https://doi.org/ 10.11646/phytotaxa.292.1.9 |
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persistent identifier |
https://treatment.plazi.org/id/03990E42-FFAF-FFB7-FF55-FF5AD921381D |
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treatment provided by |
Felipe |
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scientific name |
Elatostema tiechangense L.F. Fu, Y.G. Wei & A.K. Monro |
| status |
sp. nov. |
Elatostema tiechangense L.F. Fu, Y.G. Wei & A.K. Monro View in CoL , sp. nov. ( Fig. 1 A–E View FIGURE 1 & Fig. 2 A–D View FIGURE 2 )
Most similar to Elatostema quinquecostatum and E. nanchuanense from which it differs by the stem not being sulcate, the pubescent bracts, the smaller and pubescent staminate receptacle, and the suborbicular, smaller pistillate receptacle.
Type: — CHINA. Yunnan: Malipo County, Tiechang village, a.s.l. 1500 m, 23.334333°N, 105.151944°E (WGS84), May 3 2013, L.F. Fu & S.L. Huang FL0016 (holotype IBK!, isotype IBK!).
Perennial herb, terrestrial, monoecious. Not tuber forming. Stem 26–32 × 1–2.5 mm, erect, simple, not sulcate, drying black, densely hispid, the hairs ca 0.2 mm, with internodes 9–23 mm. Stipules 2, persistent, ca 12 × 2.5 mm, linearlanceolate, glabrous. Leaves distichous, alternate, sessile; laminae 75–110 × 22–27 mm, length:width ratio 3.4–4.1:1, oblique oblong or obovate-oblong, herbaceous; nerves pinnate, lateral nerves 9–12, at 45–60° to the mid-rib; upper surface drying black, densely hispid, the hairs ca 0.1 mm, weakly curved, appressed; cystoliths densely scattered, bacilliform, 0.1–0.2 mm; lower surface drying dark green, nerves hispid, the hairs ca 0.1 mm, weakly curved, appressed; base asymmetrical, broader-half obtuse, narrower-half cuneate; margin dentate, teeth 4–6 mm apart; apex caudate. Staminate and pistillate inflorescences borne on the same stems. Staminate inflorescences receptaculate, bracteolate, solitary, axillary, 8–10 mm; peduncle ebracteate?, ca 3 × 0.5 mm, sparsely pubescent, the hairs ca 0.1 mm, weakly curved; receptacle ca 6 × 4 mm, elliptic in transverse section, subtended by marginal bracts, yellow above and below when living, sparsely pubescent, the hairs ca 0.1 mm, weakly curved; marginal bracts 6, unequal, outer major bracts 2, inner minor bracts 4; major bracts broadly ovate, ca 5 × 4 mm, 5 longitudinal ribs extending into the apex as a corniculate protuberance, abaxial surface sparsely pubescent, the hairs ca 0.1 mm, weakly curved minor bracts ca 5 × 2 mm, obovate, abaxial surface with a single longitudinal rib extending into the apex as a corniculate protuberance, sparsely pubescent, the hairs ca 0.1 mm, weakly curved; staminate flowers pedicellate, pedicel ca 1 mm; bracteoles 2 per flower, unequal, membranous, asymmetrically ovate, semitransparent, major bracteole ca 3 × 2, minor bracteole ca 1.5 × 1 mm, glabrous, flowers ca 2 × 2 mm. Pistillate inflorescences receptaculate, bracteolate, solitary, axillary, subsessile, ebracteate?; receptacle ca 2–2.5 mm in diam., suborbicular, subtended by marginal bracts, yellow-green above and below when living; marginal bracts 6, unequal, outer major bracts 2, inner minor bracts 4; major bracts ca 1.8 × 2 mm, broadly ovate, a single longitudinal rib extending into the apex as a corniculate protuberance, abaxial surface densely pubescent, the hairs ca 0.1 mm. weakly curved, appressed; inner 4 bracts minor, ca 1.8 × 1 mm, oblong, densely pubescent, the hairs ca 0.1 mm, weakly curved. Only immature pistillate flowers seen; pedicellate; bracteoles 2 per flower, subequal, ca 1.8 × 0.2 mm, spatulate-linear, membranous, semitransparent, apex sparsely ciliate. Infructescence not seen.
Distribution: —Known only from the type locality in Yunnan Province, Malipo county, Tiechang village where Elatostema tiechangense was observed growing in a limestone cave at an elevation of 1500 m.
Etymology:— Elatostema tiechangense is named after the type locality, Tiechang village.
Additional specimen examined (paratype): — CHINA. Yunnan: Malipo County, Tiechang village, a.s.l. 1500 m, 23.334333°N, 105.151944°E (WGS84), Oct 20 2014, A.K. Monro, Y.G. Wei & L.F. Fu 7513 (IBK, BM).
Discussion: —Based on the key to Elatostema in the Flora of China (Lin et al., 2003) and Wang’s fouth revision of Chinese Elatostema (2014), Elatostema tiechangense is most similar to E. quinquecostatum W.T. Wang (1982: 24) and E. nanchuanense W.T. Wang (1980: 84) . Of these E. quinquecostatum was considered a synonymy of E. prunifolium W.T. Wang (1980: 27) by Lin & Duan (2003) but this was rejected by Wang (2010a). We agree with Wang (2010a) based on our own evaluation of the stability of the diagnostic characters ( Wang, 2010b, Fu et al., 2014).
Elatostema tiechangense is most similar to E. quinquecostatum and E. nanchuanense from which it can be distinguished based on stem, staminate peduncle, bract and receptacle morphology and pistillate bract and receptacle morphology as summarized in Table 1. We also provide a key couplet as a supplement to the key of Elatostema in Flora of China (Lin et al., 2003). This couplet should replace entry 100a in Lin et al. (2003: 130)
Key to Elatostema tiechangense , E. quinquecostatum and E. nanchuanense
Conservation Status: —A Global Conservation Assessment is presented here based on IUCN methodology (2001, 2016). Elatostema tiechangense is known from a single locality ( IUCN, 2016). At this locality the population of this species comprises ca 150 mature individuals (<250 mature individuals, criteria D1). The cave in which this species is located is close to agriculture land on a small limestone hill, which although deforested in the past, appears not to be actively disturbed. Using the IUCN (2016) methodology the Conservation Assessment for E. tiechangense would be Endangered D1 (EN): population size combined with a plausible future threat that could drive this taxon to Extinct (EX) over a very short timeframe. The authors have undertaken many fieldtrips within the region of the field locality and not encountered another population of this species. Future threats include the use of caves in agriculture to store livestock, cultivate medicinal plants or mining of the limestone hills as documented by Monro et al. (submitted).
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