Gonocarpus micranthus Thunb.

Gonocarpus micranthus subsp. micranthus is found almost throughout the range of the genus, whereas subsp. ramosissimsus Orchard is found almost entirely along the coastal regions of New South Wales and Queensland. Plants of the latter taxon are erect, 25-60 cm tall, and have diffuse inflorescences.

Herbs perennial, prostrate or decumbent, 5-15(-45) cm tall. Stem sometimes reddish, smooth, glabrous. Leaves decussate; petiole 0.5-2 mm; leaf blade ovate-cordate or elliptic, 6-17 × 4-8 mm, surfaces glabrous, base rounded, sometimes cordate, margin thickened, crenate-serrulate with 6-20 small teeth. Inflorescence an indeterminate spike, unbranched or branched; bracts lanceolate, 0.5-0.8 × 0.1-0.2 mm, membranous, margin entire; bracteoles brown, suborbicular, 0.1-0.2 × 0.1-0.2 mm, membranous, margin serrulate or entire; all bracts deciduous at anthesis. Flowers erect then nodding, 4-merous; pedicel 0.1-0.3 mm. Sepals green, deltoid, ca. 0.5 mm, sometimes with a median-basal callus, base shallowly cordate. Petals reddish, hooded, keeled, 0.8-1.2 mm, sparsely hirsute on keel. Stamens 8, ca. 1 mm. Ovary 4-loculed; styles clavate, ca. 0.8 × 0.7 mm; stigmas red, capitate, fimbriate. Fruit reddish to gray, obovoid-globose to depressed globose, 0.9-1 × 0.8-1.1 mm, 8-ribbed, glabrous. Seed 1 per fruit. Fl. Apr-Aug, fr. May-Oct.

Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shandong, Sichuan, Taiwan, Yunnan, Zhejiang [Bhutan, NE India (Assam, Sikkim), Indonesia, Japan, Korea, Malaysia, Papua New Guinea, Philippines, Singapore, Thailand, Vietnam; S and E Australia, Pacific islands (New Zealand)].

Wet or boggy places, either in open or grassy situations; 100-1800 m.

Gonocarpus citriodorus A. Cunningham; G. depressus A. Cunningham; Haloragis citriodora (A. Cunningham) Walpers; H. depressa (A. Cunningham) Walpers; H. micrantha (Thunberg) R. Brown; H. minima Colenso.

Gonocarpus micranthus is a shrub in the watermilfoil family Haloragaceae native to eastern Australia and New Zealand. Common names include creeping raspwort.