Hedyotis L. sensu lato is one of the large genera of the family Rubiaceae. It is distributed in the tropical and subtropical area worldwide and usually misiden- tified as some other species of this or other genera because of its complicated morphological variation and rich species diversity^[1]. Recently the broad sense of the genus was proved to be polyphyletic and Hedyotis s. str., along with some small genera, was proposed to be accepted in many literatures^[2-3]. Herbarium speci- men examination made us find three species belong to Hedyotis and Scleromitrion that are newly recorded in Hong Kong since the publication of Flora of Hong Kong^[4]. These species are uncommon and rarely distributed in Hong Kong.

1. Hedyotis herbaceaL., Sp. Pl. 1: 102. 1753. Ko, Fl. Reipubl. Popularis Sin. 71(1): 73. 1999. Oldenlandia herbacea (L.) Roxb., Hort. Bengal. 11. 1814. —— Type: Sri Lanka, Herb. Hermann 4: 19, Flora Zeylanica No. 65 (Lectotype: BM [BM000628086], designated by Trimen, Handb. Fl. Ceylon 2: 315. 1894). Fig. 1A.

Specimen examined: Hong Kong, Lantau Island, Keung Shan (羗山), 15 August 1998, Ying-Wai Lam 908 (HK36251).

Distribution: Widespread in tropical Africa and Asia.

Note: This species is distributed occasionally in south China^[5]. The specimen (Ying-Wai Lam 908, HK) we examined was wrongly identified as H. corymbosa in Flora of Hong Kong^[4]. Hedyotis herbacea is much different from H. corymbosa and characteristic by its usually solitary flower and erect habit. Hedyotis corymbosa is usually prostrate and has 2-5 flowers per cymose.

2. Hedyotis pumila L. f., Suppl. Pl. 1: 119. 1781. Oldenlandia pumila (L. f.) DC., Prodr. 4: 425. 1830. —— Type: India, Tranquebaria, Koenig s.n. (Lectotype: LINN 123.7, designated by Fosberg & Sachet, Allertonia 6(3): 235. 1991).小耳草(新拟) Fig. 2.

Herbs, annual or perennial. Stems diffusely branched, procumbent to prostrate, sharply angular or sulcate, subglabrous to sparsely hirtellous. Stipules truncate or triangular, 2-3 mm×0.5-2 mm, with 2-5 bristles, hirtellous. Leaves: lamina elliptic or elliptic- lanceolate, 0.7-1.8 cm×0.1-0.6 cm, apex acute, base cuneate, margins ciliate, membranous to papery, sparsely hirtellous on both sides, secondary veins not distinct; subsessile. Inflorescence axillary, 1(-2)- flowered; peduncle 0.7-1 cm long. Flowers: homo- stylous, pedicels 1-1.5 cm long, distinctly ribbed, denticulate along ribs; hypanthium ovoid, 0.3-1 mm long, calyx lobes 4, rarely 5, ovate-lanceolate or train- gular, c. 0.5 mm long, acute and dentate at margin; corolla white, c. 2 mm long, tube c. 1.2 mm long, pubescent at throat, lobes 4, ovate, 0.5-0.8 mm×c. 0.5 mm, acute and incurved at apex; stamens 4, filaments inconspi- cuous, 0.2-0.3 mm long, adnate to sinus between corolla lobes, anthers c. 0.2 cm long, ovoid, exserted at corolla throat; ovary c. 0.3 mm long, ovules many on a submedian oblong placenta, style 0.5-0.7 mm long, stigma clavate, 0.3-0.5 mm long, bilobed, fleshy, tufted-hairy, exserted above the anthers. Capsule ellipsoid or oblong-ovoid, 2-3 mm×2.5-3 mm, distinctly ribbed, glabrous, dehiscent septicidally along the top. Seeds many, angular, c. 0.5 mm×0.3 mm, exotesta strongly reticulate, brownish.

Specimen examined: Hong Kong, Hong Kong Island, Bowen Road (宝云道), October 1979, L. T. Lo 543 (HK33759).

Distribution: Bangladesh, India, Indonesia, Malaysia, Myanmar, Singapore, Vietnam; introduced in Africa and Jamaica.

Note: This species was not recorded in China previously^[5].

3. Scleromitrion koanum (R. J. Wang) R. J. Wang, J. Trop. Subtrop. Bot. 22(5): 440. 2014. —— Hedyotis koana R. J. Wang, Acta Phytotax. Sin. 45(5): 696. 2007. Type: CHINA. Guangdong Province, Huidong County, Gangkou town, Pingshizhou Island, seaside, 12 August 1990, Binghui Chen 524 (holotype: IBSC). Fig. 1B.

Specimens examined: Hong Kong, Ping Yeung (坪洋), 3 September 2014, K. Y. Tam s.n. (HK004 4228); Hong Kong, New Territory, Fo Tan Road (火炭路), riverbank, 22 April 1979, S. L. Thrower 1467 (CUHK).

Distribution: Fujian, Guangdong, Guangxi, Hainan, Hunan, Jiangxi^[6].

Note: Scleromitrion koanum was similar to S. pinifolium (Wall. ex G. Don) R. J. Wang^[7] in their linear leaves, terminal or upper axillary inflorescence, but differs from the latter in having 0.5-1 mm (vs. 15-20 mm in S. pinifolium) long flower pedicels, 3- 10 flowers (vs. 1-3 flowers in S. pinifolium) per inflorescence and hispid (vs. glabrous in S. pinifolium) capsule. This species usually grows nearby the water or sandy area. Although many specimens collected previously, it is now very rare in the field because of the disturbance to its habit.

Acknowledgments   I am grateful to Dr. Kuen-Shum Pang, Dr. Jenny Lau, Mr. Ying-Wai Lam and Mr. Kai-Yip Tam from the herbarium of Agriculture, Fisheries and Conservation Department, the Government of the Hong Kong Special Admi- nistrative Region (HK), Dr. Tai-Wai Lau from the herbarium of the Chinese University of Hong Kong (CUHK) for their kind assistance during the specimen examination.