Pternopetalum paucifoliolatum J.F. Ye, X.Jie Li & Ce H.Li, 2020
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publication ID |
https://dx.doi.org/10.3897/phytokeys.166.54646 |
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persistent identifier |
https://treatment.plazi.org/id/928DB6A6-D337-5CF3-9521-9C87C9CE2E95 |
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treatment provided by |
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scientific name |
Pternopetalum paucifoliolatum J.F. Ye, X.Jie Li & Ce H.Li |
| status |
sp. nov. |
Pternopetalum paucifoliolatum J.F. Ye, X.Jie Li & Ce H.Li sp. nov. Figs 1 View Figure 1 , 2 View Figure 2 , 3 View Figure 3
Type.
China. Sichuan, Emeishan County, Sixigou Scenic Area (29.40°N, 103.38°E), on moist limestone cliff, at an altitude of ca 850 m a.s.l., 02 May 2020, in fruit, X. J. Li CPG41074 (holotype: PE!).
Etymology.
The specific epithet refers to the 3-7 (rare simple) leaflets of this species which differentiate it from all other species of Pternopetalum .
Diagnosis.
Pternopetalum paucifoliolatum differs from P. porphyronotum J.B. Tan (2018: e01549) by shorter plants (5-7 cm), 3-7 leaflets (vs. 5-17), leaflet margin white-ciliate, rays 5-8 (Table 1 View Table 1 ).
Plants 5-7 cm tall. Taproot slender, ca. 3 cm long. Stem 1, unbranched, glabrous. Basal leaves petiolate; petioles 0.7-4 cm; ultimate segments ovate-triangular, 1.5-6 × 0.6-1.4 cm, 1-pinnate, occasionally simple; pinnae 1-3 pairs, broadly ovate, 3-6 × 3-5 mm, lobed, margin white-ciliate, both surfaces glabrous, adaxially green, abaxially purple-red. Cauline leaves 1 or occasionally absent, similar to basal, occasionally linear-lanceolate, 8-12 × 5-6 mm. Umbels terminal, bracts absent, rays 5-8, 10-12 mm, subequal; bracteole 1, linear-lanceolate, 0.5-1 mm; umbellules 2(-3)-flowered; pedicels 0.2-2 mm. Calyx teeth distinct, triangular, ca. 0.3 mm. Petals white, oblong-obovate. Stylopodium conic; style ca. 1 mm, reflexed in the top half, about two to three times as long as the stylopodium. Fruit ovoid, 0.7-1.2 × 0.8-1 mm.
Phenology.
Pternopetalum paucifoliolatum is flowering from March to April, and fruiting from May to June.
Distribution and habitat.
Pternopetalum paucifoliolatum is only known from its type locality, Sixigou Scenic Area, Emeishan City, Sichuan Province, China. It grows together with grass or mosses on a moist limestone cliff, at 850 m a.s.l. Associated species include Adiantum sp., Begonia wilsonii Gagnep., Dryopteris sp., Mitreola pedicellata Benth., Pteris gallinopes Ching ex Ching & S. H. Wu., Pteris sp., Selaginella sp., Cleistoblechnum eburneum (Christ) Gasper & Salino, Viola davidii Franch.
Vernacular name.
少羽囊瓣芹 [shǎo yǔ náng bàn qín].
Conservation status.
Pternopetalum paucifoliolatum is only distributed in Sixigou Scenic Area. We have gone all out to estimate the population size in this area, but found it only growing on one limestone cliff ca 850 m a.s.l., with no more than 200 individuals totally. Sadly, a new built highway will pass by the locality and serves as an entrance to the highway, which will destroy the habitat. Based on this current information and according to IUCN red list criteria ( IUCN 2017), P. paucifoliolatum should be ranked as 'Critically Endangered’ (CR C2a (ii)).
Discussion.
Pternopetalum paucifoliolatum differs markedly from the other known species of this genus by the following characters: basal leaves 1-pinnate, occasionally simple; pinnae 1-3 pairs. It is somewhat similar to P. porphyronotum J.B. Tan by 1-pinnate leaves and the abaxially purple-red leaflets, solitary stem and terminal umbel, but differs from it by being 5-7 cm tall (vs. 8-15 cm), stem 1 (vs. 1, occasionally 2), abaxial surface of basal leaves purple-red (vs. purple-red, paler along the edge), rays 5-8, subequal (vs. 8-20, unequal) (Table 1 View Table 1 ).
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