2. 英华书院, 中国香港;
3. 香港空运货站有限公司, 中国香港
2. Ying Wa College, Hong Kong SAR, China;
3. Hong Kong Air Cargo Terminals Limited, Hong Kong SAR, China
Hong Kong is located on the south coast of China. The territory's 1 106.66 km2 land area consists of Hong Kong Island, the Kowloon Peninsula and the New Territories, including 262 islands. Though well known as a metropolis, only 25% of its land has been developed, and 41.7% of the land is country parks or nature reserves.
Hong Kong lies at the northern fringe of the tropics with a mean annual rainfall that ranges from about 1 400 mm at the outlying island Ping Chau to more than 3 000 mm in the vicinity of the highest peak, Tai Mo Shan. The warm and moist climate has fostered a remarkably diverse flora within its small land area. In the 2012 edition of the Check List of Hong Kong Plants, 2 175 native vascular plant species or varieties were recorded. Since the last update of the checklist, a number of new species, e.g. Carpinus insularis, Gastrochilus kadooriei and Thismia hongkongensis have been described and more than ten new records have been reported[8-11].
In this article, we report 17 vascular plant species and one genus newly recorded to the flora of Hong Kong. The voucher specimens are deposited in the herbarium of Kadoorie Farm and Botanic Garden (KFBG). The original vegetation in Hong Kong has been severely damaged after centuries of human disturbance. Most of the newly recorded species were discovered in small patches of remote secondary montane or ravine forest, which have suffered a lesser degree of disturbance. This highlights the importance of fragmented forest in biodiversity conservation, and suggests that further exploration of these and similar locations may well result in more discoveries.Pteridophytes Aspleniaceae
1. Hymenasplenium apogamum (N. Murak. & Hatan.) Nakaike无配膜叶铁角蕨(Fig. 1: A-B)
In New Fl. Japan, 841, 1992; FOC, 2-3: 314, 2013; HPCC (Higher Plants of China in Colour), 2: 139, 2016.——Asplenium apogamum N. Murak. & Hatan., in J. Fac. Sci. Univ. Tokyo, Sect. 3, Bot., 14: 193, 1988.
Distribution: China (Taiwan, Yunnan), Japan, Laos, Thailand, Vietnam.
Specimens examined: New Territories, Ng Tung Chai, along a rocky stream in a forested valley, alt. 258 m, 16 February 2019, LIU Jin-gang, JG0700 (KFBG); New Territories, Lai Tau Shek, creeping on rocks at the edge of a stream, in the shade of secondary forest, alt. 49 m, 30 April 2020, LIU Jin-gang JG0866 (KFBG).
Notes: This species is recognised by the quadran- gular-trapeziform pinnae, whose acroscopic side is truncate and parallel to the rachis. Two small popu- lations were discovered.Polypodiaceae
2. Leptochilus decurrens Blume似薄唇蕨(Fig. 1: C-D)
In Enum. Pl. Javae., 2: 206, 1828; FOC, 2-3: 837, 2013; FRPS, 6(2): 262, 2000.
Distribution: China (Guangxi, Guizhou, Hainan, Taiwan, Yunnan), Bhutan, India, Indonesia, Malaysia, Myanmar, Nepal, New Guinea, Philippines, Sri Lanka, Thailand, Vietnam, Pacific islands.
Specimens examined: New Territories, Ho Pui Reservoir, on fertile and wet soil in an area with slowly seeping water, in dense forest, alt. 320 m, 8 April 2020, LIU Jin-gang JG0834 (KFBG).
Notes: Leptochilus decurrens is recognised by its narrowly ovate to ovate sterile fronds with decurrent base, and linear fertile fronds with sori arranged throughout the abaxial surface. This species is very similar to L. hemionitideus, but the latter has mono- morphic fronds. At the habitat, we also found a few individuals whose fertile fronds are lanceolate with separate short-linear sori. These individuals may be L.×beddomei (synonym: Colysis×beddomei), the hybrid between L. decurrens and L. hemionitideus. More field observations and anatomical evidence are needed to confirm the hybrid.Angiosperms Araceae
3. Amydrium hainanense (H. Li, Y. Shiao & S. L. Tseng) H. Li穿心藤(Fig. 1: E-G)
In Reipubl. Popularis Sin., 13(2): 24, 1979; FOC, 23: 10, 2010.——Epipremnopsis hainanensis H. Li, Y. Shiao & S. L. Tseng, Acta Phytotax. Sin., 15(2): 102, 1977.
Distribution: China (Guangdong, Guangxi, Hai- nan, Hunan, Yunnan), Vietnam.
Specimens examined: Lantau Island, Sunset Peak, liana, creeping on a tree trunk, in dense forest in a valley, alt. 499 m, 10 April 2020, LIU Jin-gang JG0839 (KFBG).
Notes: Amydrium hainanense is recognised by its leaf blade with perforations of irregular sizes. A few individuals, including seedlings were discovered in a forested valley. Its relative, A. sinense was also recently reported as a new record to the flora of Hong Kong.Rosaceae
4. Laurocerasus hypotricha (Rehder) T. T. Yu & L. T. Lu毛背桂樱(Fig. 1: H-J)
In Bull. Bot. Res., 4(4): 44, 1984; FOC, 9: 427, 2003; FRPS, 38: 113, 1986.
Distribution: China (Fujian, Guangdong, Guang- xi, Guizhou, Jiangxi, Sichuan, Yunnan).
Specimens examined: Lantau Island, Sunset Peak, streamside in a forested valley, alt. 460 m, 21 December 2020, HON Cheuk-hei HH1033 (KFBG); in the same area, alt. 447 m, 10 April 2019, LIU Jin- gang JG0838 (KFBG).
Notes: Laurocerasus hypotricha is very similar to L. zippeliana, except that the branchlets, petioles and leaf blades are densely pubescent abaxially. Eight trees (7-8 m tall) were observed. These two species co-occur in the same forested valley. We have also noted that L. hypotricha (synonym: Prunus macro- phylla var. puberifolia) has been treated as a variety of L. zippeliana (synonym: Prunus macrophylla). The taxonomic relationship between L. hypotricha and L. zippeliana merits further study.
5. Rubus buergeri Miq. 寒莓(Fig. 2: A-B)
In Ann. Mus. Bot. Lugduno-Batavi., 3: 36, 2003. 1867; FOC, 9: 258, 2003; FRPS, 37: 171, 1985.
Distribution: China (Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hubei, Hunan, Jiangsu, Jiangxi, Sichuan, Taiwan, Yunnan, Zhejiang), Japan, Korea.
Specimens examined: Lantau Island, Lantau Peak, in grassland, in the saddle between two peaks, alt. 700 m, 3 May 2020, LIU Jin-gang JG0881 (KFBG).
Notes: Rubus buergeri is recognised by simple, densely tomentose-villous leaves with ovate to sub- orbicular, palmately 5-veined blades and caducous, palmatipartite or pinnatipartite stipules. Only a few individuals were discovered.Fagaceae
6. Quercus pachyloma Seemen毛果青冈(Fig. 2: C-E)
In Bot. Jahrb. Syst., 23(Beibl. 57): 54, 1897.——Cyclobalanopsis pachyloma (Seemen) Schottky In Bot. Jahrb. Syst., 47: 650, 1912; FOC, 4: 399, 1999.
Distribution: China (Fujian, Guangdong, Guang- xi, Guizhou, Hunan, Jiangxi, Taiwan, Yunnan).
Specimens examined: Lantau Island, Sunset Peak, in ravine forest on a mountain slope, alt. 310 m, 17 January 2019, HON Cheuk-hei HH0761 (KFBG); Lantau Island, Lantau Peak, streamside in a forested valley, alt. 156 m, 14 February 2019, HON Cheuk-hei HH0776 (KFBG); in the same area, alt. 176 m, 3 May 2020, LIU Jin-gang JG0871 (KFBG).
Notes: Quercus pachyloma differs from other Quercus species reported from Hong Kong by having campanulate, sometimes corrugated, densely tomen- tose cupules. Two populations (20-30 trees in total) were observed beside streams in valleys. The largest tree was ca. 8 m tall, 35 cm in DBH.
7. Lithocarpus glaucus Chun & C. C. Huang ex H. G. Ye粉绿柯(Fig. 2: F-H)
In Nord. J. Bot., 24(3): 257, 2004.
Distribution: China (Guangdong, Guangxi).
Specimens examined: New Territories, Tai Mo Shan, 11 May 1886, Westland s.n. (IBSC, 10689-photo); in the same area, along a stream in montane forest, alt. 748 m, 30 October 2019, WONG Chukkwan MW0301 (KFBG); in the same area, alt. 618 m, 10 May 2020, LIU Jin-gang JG0902 (KFBG).
Notes: Lithocarpus glaucus was described in 2004. It is similar to L. hancei, but differs from the latter in having larger leaves, more prominent veins and longer petioles. The inflorescence rachis is glabrous, and the cupules only enclose the base of the nuts. At the same location, its flowering period is one to two months later than L. hancei (April-May vs. March). About 10 individuals (6-10 m tall) were discovered at the side of a stream, in forest.
The earliest specimen we examined was collected by Westland in 1886, from the same place as the specimens we collected from Tai Mo Shan. Westland's specimen was first identified as Quercus synbalanos Hance by Chun Woon Young, but was identified as L. glaucus by H. G. Ye in 2003. However, it was not cited in the formal description of L. glaucus.
8. Lithocarpus longanoides C. C. Huang & Y. T. Chang龙眼柯(Fig. 2: I)
In Guihaia, 8(1): 25, 1988; FOC, 4: 359, 1999; FRPS, 22: 166, 1998.
Distribution: China (Guangdong, Guangxi, Yunnan).
Specimens examined: New Territories, Ma On Shan, in montane broad-leaved evergreen forest, alt. 580 m, 23 November 2018, WONG Chuk-kwan MW0229 (KFBG); in the same area, alt. 562-584 m, 16 May 2020, LIU Jin-gang JG0907-JG0909 (KFBG).
Notes: Lithocarpus longanoides is recognised by ovate or lanceolate rigidly papery leaf blades, with entire margins; globose to slightly depressed cupules, usually enclosing the nut to 80%, with the wall being less than 1 mm thick. Its fruits are similar to L. fenestratus, but the two species can be easily distin- guished by their leaves. More than 10 trees (6-10 m tall) were found in montane forest.Rutaceae
9. Murraya euchrestifolia Hayata豆叶九里香(Fig. 2: J-K)
In Icon. Pl. Formos., 6: 11, 1916; FOC, 11: 87, 2008; FRPS, 43(2): 146, 1997.
Distribution: China (Guangdong, Guangxi, Gui- zhou, Hainan, Taiwan, Yunnan).
Specimens examined: Lantau Island, Sunset Peak, in semi-open forest in a ravine, alt. 130 m, 16 December 2018, HANG King-yeung HKY0345 (KFBG).
Notes: Murraya euchrestifolia is recognised by 5-9-foliolate compound leaves, with alternate or subopposite leaflets; leaflet blades ovate to elliptic and tertiary veins slightly prominent adaxially. Only two individuals (ca. 5 m tall) were observed in the lower part of a ravine.Ebenaceae
10. Diospyros chunii F. P. Metcalf & L. Chen崖柿(Fig. 3: A-C)
In Lingnan Sci. J., 14: 618, 1935; FRPS, 60(1): 138, 1987; FOC, 15: 232, 1996.
Distribution: China (Hainan).
Specimens examined: Lantau Island, Sunset Peak, streamside in a forested valley, alt. 452 m, 8 January 2020, LIU Jin-gang JG0813 (KFBG); in the same area, alt. 483 m, 18 April 2020, LIU Jin-gang JG0854 (KFBG).
Notes: Diospyros chunii is recognised by brownish- yellow tomentose buds and young branchlets; oblong to oblong-lanceolate, grey-green abaxial leaf blades, with a pubescent midrib and veins. Fifteen individuals were discovered in the forest, by the upper part of a stream. The largest individual is ca. 6 m tall, 12 cm in DBH. Seedlings were observed around the mature trees.Primulaceae
11. Myrsine linearis (Lour.) Poir. 打铁树(Fig. 3: D-F)
In Encycl. Suppl., 3: 709, 1813; FOC, 15: 37, 1996; FRPS, 58: 131, 1979.
Distribution: China (Guangdong, Guangxi, Gui- zhou, Hainan), Vietnam.
Specimens examined: New Territories, Ma On Shan, in semi-open forest close to a stream, alt. 46 m, 27 December 2018, LIU Jin-gang JG0682 (KFBG); New Territories, Nam Chung, in open forest, alt. 206 m, 4 January 2020, LIU Jin-gang JG0806 (KFBG).
Notes: Myrsine linearis is similar to M. seguinii, but differs in having smooth branchlets (vs. rugose), a papery leaf blade (vs. leathery), and a broadly rounded to truncate, sometimes retuse (vs. acute) leaf apex. This species is relatively common in the secondary forest along the ridge of a hill in Nam Chung.
12. Myrsine semiserrata Wall.针齿铁仔(Fig. 3: G-I)
In Roxburgh, Fl. Ind., 2: 293, 1824; FOC, 15: 36, 1996; FRPS, 58: 126, 1979.
Distribution: China (Guangdong, Guangxi, Gui- zhou, Hubei, Hunan, Sichuan, Xizang, Yunnan), India, Myanmar, Nepal.
Specimens examined: New Territories, Pat Sin Leng, streamside in forest, alt. 320 m, 21 December 2017, HON Cheuk-hei HH0451 (KFBG); in the same area, 12 April 2020, HON Cheuk-hei HH1092, KFBG; in the same area, 1 May 2020, LIU Jin-gang JG0867 (KFBG).
Notes: Myrsine semiserrata is recognised by angular branchlets, rhomboid to lanceolate leaf blades and a sharply toothed leaf margin at the apical part. For this population, petals are usually 5-merous, rarely 4-merous. Ten individuals (1-2 m tall) were observed.Theaceae
13. Schima remotiserrata Hung T. Chang疏齿木荷(Fig. 3: J-L)
In Acta Sci. Nat. Univ. Sunyatseni., 22(3): 60, 1983; FOC, 12: 423, 2007; FRPS, 49(3): 221, 1998.
Distribution: China (Fujian, Guangdong, Guang- xi, Hunan, Jiangxi).
Specimens examined: New Territories, Ma On Shan, along a mountain ridge in open forest, alt. 588 m, 26 April 2020, LIU Jin-gang JG0861 (KFBG).
Notes: This species differs from Schima superba by its thickly leathery (vs. thinly leathery) leaf blades, sparsely serrate (vs. obtusely crenate) leaf margin, 2- 4 cm (vs. 1-2.5 cm) long petiole, stout (vs. less stout) pedicel, yellowish (vs. white) petals, and flowering in Hong Kong in July (vs. May-June). S. remotiserrata is only observed in the forest at a relatively higher altitude on Ma On Shan, while S. superba is widely distributed in the forests and Fengshui woods in Hong Kong. The observed population is growing on a sunny and exposed ridge and all the individuals are less than 5 m tall and shrub-like. This species is relatively common along the ridge of Ma On Shan.Apocynaceae
14. Heterostemma brownii Hayata台湾醉魂藤(Fig. 4: A-C)
In J. Coll. Sci. Imp. Univ. Tokyo, 30: 199, 1911; Phytotaxa, 263(1): 6, 2016; FOC, 16: 263, 1995.
Distribution: China (Fujian, Guangdong, Guang- xi, Guizhou, Hainan, Sichuan, Taiwan, Yunnan).
Specimens examined: New Territories, Ng Tung Chai, liana, climbing on trees and over rocks, stream- side in a forested valley, alt. 393 m, 25 December 2019, LIU Jin-gang JG0791 (KFBG); in the same area, alt. 430 m, 9 May 2020, LIU Jin-gang JG0895 (KFBG).
Notes: Heterostemma brownii is recognised by its rounded to broadly cuneate leaf base, abaxially winged basal veins, and linear-lanceolate, striped follicles. Two populations were observed along the stream in a remote valley. The population by the upper part of the stream occupied an area of 30 m2. Hetero- stemma Wight & Arn. is a newly recorded genus to Hong Kong.
15. Urceola napeensis (Quint.) D. J. Middleton华南水壶藤(Fig. 4: D-E)
In Kew Bull., 49(4): 764, 1994; Blumea, 41(1): 102, 1996; FOC, 16: 184, 1995.
Distribution: China (Guangdong, Guangxi, Hainan), Laos, Thailand, Vietnam.
Specimens examined: New Territories, Tai Mo Shan, liana, climbing on trees by the side of a stream, alt. 505 m, 10 May 2020, LIU Jin-gang JG0903 (KFBG); New Territories, Ma On Shan, climbing on trees in montane forest, alt. 588 m, 16 May 2020, LIU Jin- gang JG0906 (KFBG).
Notes: Urceola napeensis is similar to U. micrantha in having elliptic to ovate leaves and terminal or upper axillary cymes, which usually form a panicle. It can be distinguished from the latter by its smaller inflore- scence (2-9 cm long vs. 5.8-18 cm long), longer corolla lobes (much longer than the tube vs. relatively equal), and parallel, stipitate (vs. divergent, sessile) follicles.Lentibulariaceae
16. Utricularia minutissima Vahl斜果挖耳草(Fig. 4: F-G)
In Enum. Pl., 1: 204, 1804; FOC, 19: 482, 2011; FRPS, 69: 593, 1990.
Distribution: China (Fujian, Guangdong, Guang- xi, Jiangsu, Jiangxi), Cambodia, India, Indonesia, Japan, Laos, Malaysia, Myanmar, Papua New Guinea, Philippines, Sri Lanka, Thailand, Vietnam, Australia.
Specimens examined: New Territories, Pat Sin Leng, on the sunny, sandy banks of streams, alt. 180 m, 16 December 2018, CHUNG Wai-kwong CMK064 (KFBG).
Notes: Utricularia minutissima is similar to U. caerulea, but differs in the shape of the lower lip (3- lobed vs. broadly ovate). Several populations were discovered along streams in Pat Sin Leng. This species co-occurs with other wetland herbs, e.g., U. caerulea, Eriocaulon nantoense and Stylidium uliginosum.Asteraceae
17. Blumea aromatica DC. 馥芳艾纳香(Fig. 4: H-J)
In Prodr., 5: 446, 1836; FOC, 20-21: 833, 2011; FRPS, 75: 20, 1979.
Distribution: China (Fujian, Guangdong, Guang- xi, Guizhou, Hunan, Jiangxi, Sichuan, Taiwan, Yunnan, Zhejiang), Bhutan, India, Myanmar, Nepal, Thailand, Vietnam.
Specimens examined: New Territories, Ng Tung Chai, at the edge of a stream in a forested valley, alt. 368 m, 19 January 2019, Craig WILLIAMS CW1071 (KFBG).
Notes: Blumea aromatica is recognised by its viscid-tomentose branches and irregularly biserrate leaf margin. Less than 10 individuals were observed. The largest one was 2.5 m tall, with a woody lower stem, while the rest were all below 1 m, with herba- ceous stems. The population is restricted to a remote valley.
Acknowledgments We thank Mr. DIXON Clive for showing us the location of Leptochilus decurrens and Mr. CHEUNG Paul for sharing the geographical coordinates of Blumea aromatica. We also thank Mr. CHEN Sheng (South China Agricultural Univer- sity) and ZHOU Xin-xin (South China Botanical Garden, Chinese Academy of Sciences) for the verification of Myrsine semiserrata.
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