Description from Flora of China
Veronica anagallis-aquatica Linnaeus subsp. undulata (Wallich ex Jack) Elenevsky.
Perennials, rarely annuals; stems, inflorescence axes, pedicels, calyces, and capsules sparsely with capitate glandular hairs. Rhizomes inclined. Stems erect or procumbent at base, branched or not, 10-100 cm tall, succulent. Leaves sessile, amplexicaul upward; leaf blade mostly elliptic to ovate, sometime ovate-oblong or linear-lanceolate, rarely lanceolate, 2-10 X 1-3.5 cm, margin usually serrate. Racemes axillary, longer than leaves, 1-1.5 cm wide, many flowered. Pedicel 3-5 mm, as long as or shorter than bract, straight, at a right angle with inflorescence axis, patent in fruit. Calyx 4-lobed; lobes ovate-lanceolate, ca. 3 mm, equal in size, erect to patent, not appressed to capsule in fruit, apex acute. Corolla pale blue, pale purple, or white, rotate, 4-5 mm in diam.; tube short; lobes broadly ovate, slightly unequal in width. Stamens shorter than corolla. Capsule subglobose, as long as wide and as calyx, slightly compressed, apex rounded and slightly notched. Style 1-1.5 mm. Seeds ca. 30 per capsule, slightly flattened, convex on both sides. Fl. Apr-Sep. 2n = 18.
Veronica undulata and V. anagallis-aquatica differ morphologically and geographically, with the latter not occurring in SE China.
Plants with galls are used to stimulate blood circulation, relieve pains, stimulate menstrual flow, and stop bleeding.
By water or in swamps; below 2800 m. Throughout China except Nei Mongol, Ningxia, Qinghai, Xizang [E Afghanistan, N India, Japan, Korea, Laos, Nepal, Pakistan, Thailand, Vietnam].