Cheilotheca crocea L.Wu & Yan Liu, 2016

Wu, Lei, Jiang, Ri-Hong, Yang, Jin-Cai & Liu, Yan, 2016, New records of Cheilotheca (Ericaceae, Monotropoideae) from China including the description of a new species, Phytotaxa 260 (2), pp. 193-198 : 194-196

Cheilotheca crocea L.Wu & Yan Liu , sp. nov., Figs. 1 & 2

Type:— CHINA. Guangxi: Nanning city, Damingshan National Nature Reserve , 23°30′ N, 108°28′ E, elevation ca. 840 m, 4 August 2010, L. Wu and R. H. Jiang D 0199 (holotype IBK!; isotypes HAST!, IBK!) .

Diagnoses:— The new species is similar to C. malayana with white stem, scale-like leaves, oblong petals with thickened apex, erect flowers at anthesis, 1-locular ovary, parietal placentation and erect berry, but it can be easily distinguished from the later by the equal length filaments and elongate anthers with 2-longitudinal slits at dehiscence.

Description:— Herbs, achlorophyllous, saprophytic, white when fresh, rather fleshy, becoming black when dry. Stems suberect, solitary or 2–5-branched, 10–25 cm tall, 4–8 mm in diam. Leaves scale-like, alternate, sessile, densely crowded, oblong to oblong-lanceolate, 7–16 × 6–10 mm, margin entire or erose to irregularly toothed, apex obtuse, below soil level smaller and more densely crowded than upper ones, glabrous. Flowers terminal, campanulate, 1.5–2.5 cm long, 8–15 mm in diam. Sepals 3–5, scale-like, appressed to petals, lanceolate to oblong, 10–15 × 6–10 mm, glabrous, apex acute to obtuse. Petals 3, free or united at base, apical 2/3 orange, basal 1/3 white, obovate-oblong, 20–27 × 7–12 mm wide, fleshy, abaxially glabrous, adaxially usually densely villous, margin entire or irregularly toothed, apex rounded. Stamens 6; filaments compressed, 15–17 × 1–1.2 mm, villous; anthers creamy-yellowish, elongate, 4–5 mm long, confluent at apex, dehiscent by 2 longitudinal slits. Disk nearly entire. Ovary glabrous, 1- locular, placentation parietal; style 4–6 mm long, 2–2.5 mm across; stigma capitate, yellow-brown, slightly depressed at apex, glabrous. Berries erect, ellipsoid-globose, 1.8–2.5 cm long.

Distribution and habitat: —As other plants in Monotropoideae , the new species is saprophytic and depends on fungal associations for nutrition. It lives in shady slopes under evergreen broadleaf forest of more than 95% coverage at elevation between 840–1000 m. The dominant stand cover including tree species of Lauraceae , Fagaceae , Euphorbiaceae , Ebenaceae , and Myrtaceae . The mean annual rainfall and temperature are 3 000 mm and 21°C, respectively, in Damingshan National Nature Reserve, Nanning, Guangxi ( Li 2003) ( Fig. 3 ).

Phenology: —Flowering from August to September, and fruiting from September to October.

Etymology: —The specific epithet is derived from the colour of the petals.

Conservation status: —The new species is only found in Damingshan National Nature Reserve recently,comprising two populations. Although the area has been well-protected, the population size of both the two distributing sites is small, of which, one has 33 individuals, while another, ca. three kilometres away, with only 28 plants. Furthermore, both the two sites are located near the road to the holiday resorts and are thus subjected to serious disturbances from tourism. The species is therefore temporarily assigned as ‘Critically Endangered’ (CR B2a & C2aì) following the IUCN (2008) guidelines.

Additional specimens examined (paratypes): — CHINA. Guangxi: Nanning city, Damingshan National Nature Reserve, 1 October 2010, L.Wu D1360 (IBK!), 10 September 2011, L.Wu & M.T.Liu D2994 (IBK!), 11 September 2011, L.Wu & M.T. Liu D3500 (IBK!).

Notes: —As mentioned before, three species are recognized in Cheilotheca , of which, one is from Eastern India, and the rest two are both from Malay Archipelago. So the discovery of the new species largely enlarges the distribution of the genus. The new species is most similar to C. malayana , but differs from the latter in its scale-like leaves white (vs. leaves upwards lurid-purple or waxy white), sepals 10–15 × 6–10 mm (vs. sepals 15–18 × ca. 5 mm), petals adaxially usually densely villous throughout (vs. petals apical 2/3 adaxially densely to sparingly shortly hairy), filaments equal in length (vs. filaments unequal in length, the outer ones are shorter than the inner ones) and anthers elongate with 2- longitudinal slits at dehiscence (vs. anthers short with a single terminal slit).

Moreover, it is worth to mention that Cheilotheca sleumerana is a very strange plant in this genus. Based on its original description ( Keng 1974), the flowers of C. sleumerana are nodding at anthesis, the number of its stamens and disk lobes are both 8, and the filaments are subglabrous, which suggests it would be more likely a member of Monotropa . For lacking of materials in hand especially the fruiting plants, however, we tentatively accept it in C heilotheca. The following key is provided to the species of Cheilotheca .

Figures

FIGURE 1. Cheilotheca crocea. A: Flowering plant. B: Fruiting plant. C: Flower, viewed from the top. D: Petal, adaxial view. E: Pistil. F: Stamen. G: Fruit, transverse section. Vouchers: A, C–F, L.Wu & R.H.Jiang D0199; B, G, L. Wu & M.T. Liu D2994. Artist: Wen-Hong Lin.

FIGURE 2. Cheilotheca crocea. A, B: Flowering plant. C: Flowers, viewed from above. D: Flower, dissected to show gynoecium and androecium. E, F: Juvenile plants. G, H: Fruiting plants. I: Plant with fruit fallen. J: Fruit. K: Stem base. L: Transverse sections of the fruit. Vouchers:A–D, L.Wu & R.H.Jiang D0199; I, L. Wu D1360; G, H, J–L, L. Wu & M.T.Liu D2994.

FIGURE 3. Known distribution of Cheilotheca crocea (●) in Guangxi Zhuangzu Autonomous Region, China.