Lysimachia japonica Thunb. var. formosana (Honda) S. S. Ying, Colour. Illustr. Pl. Taiwan, Pt. 4; Colour. Illustr. Herbac. Pl. Taiwan, Vol. 1: 152. 1980.
A prostrate or decumbent, perennial herb; stems angular, pubescent. Leaves opposite, ovate to nearly reniform, with pellucid dots, 1-3 cm long, 1-1.5 cm wide, rounded or acute at apex, rounded or cuneate at base, the petioles 4-8 mm long. Flowers axillary, yellow, 5-7 mm across; pedicels 3-8 mm long, pubescent; sepals 5, linear-lanceolate, pubescent; corolla lobes obovate, 5-7 mm long, without black dots on corolla-lobes, but with pellucid dots. Capsules brown, globose, pubescent, shorter than calyx, longitudinally dehiscent; seeds black.
TAIPEI: Yangmingshan, Liu 222, Nankang, Peng 9353. KEELUNG: Wutu, Peng 12986; Hoping Island, Wang 925. HSINCHU: Shihtoushan, Peng 14841. NANTOU: Lushan, Kao 7954; Sun Moon Lake, Kuo 8853.
Distributed in Japan, the Ryukyus, Malaysia, and SE China. Taiwan in field and roadside in lowlands to medium altitudes, in the central and northern parts. Flowering mostly in February to April.
Phenology: perennial
Life form: herb
Root: rooting at node or not: rooting at node
Stem: present
Stem: type: decumbent, prostrate at base
Stem: shape: angled
Stem: indumentum: hairy
Leaf: position: cauline
Phyllotaxy: opposite
Leaf: petiole: petiolate
Leaf: petiole length (mm): 3-8
Leaf: blade shape: ovate, reniform
Leaf: blade apex: acute, rounded
Leaf: blade base: rounded, cuneate
Leaf: blade margin: entire
Leaf: blade surface: dotted
Leaf: blade texture: herbaceous
Leaf: blade length (mm): 10-15
Leaf: blade width (mm): 10-15
Inflorescence: solitary
Inflorescence: position: axillary
Scape: absent
Peduncle: length (mm): 3-8
Bract: absent
Calyx: shape: 5-parted
Sepal: shape: linear, lanceolate
Sepal: margin: entire
Sepal: length (mm): 4-8
Sepal: width (mm): 1-2.5
Corolla: color: yellow
Corolla: shape: rotate
Lobe: margin: entire
Lobe: length (mm): 3-7
Lobe: width (mm): 2-3
Filament fused into a ring or not: filament fuse to a ring
Filament and anther relative length: filament about equal to anther
Stamens protruding from corolla or not: Stamens protuding from corolla
Capsule: dehiscence type: longitudinal
Distribution: low elevation cultivated field, mid elevation
