Pseudostellaria is a genus of roughly 18–24 species of perennial herbs in the family Caryophyllaceae (the pink family), within the order Caryophyllales. The genus was formally described by Pax in 1934, though it had previously been placed under the synonym Krascheninikovia Turczaninow. Most species are native to East and North Asia, with the greatest diversity in China (nine species, two of them endemic); one species (P. europaea) occurs in Europe, and two are found in North America.
Plants grow from distinctive fusiform, ovoid, or subglobose root tubers. Stems are erect or ascending, sometimes creeping, and leaves are ovate to linear-lanceolate without stipules. A defining characteristic of the genus is its dimorphic flowering strategy: showy chasmogamic (open-pollinated) flowers are produced in distal leaf axils or terminal cymes and have five white, entire or slightly notched petals, five sepals, and ten stamens; smaller cleistogamic (self-fertilizing, closed) flowers are produced in proximal axils and have reduced or absent petals and fewer stamens. Capsules are 2–4-valved, and the seeds are few, relatively large, somewhat flattened, and smooth to tuberculate with a curved embryo.
Pseudostellaria is morphologically similar to the closely related genus Stellaria (chickweeds), but differs in its tuberous roots, capsule structure, and the shallower notches of its petals. The medicinally important species P. heterophylla (known in Chinese herbal medicine as 太子参, tài zǐ shēn) has its roots traded and cultivated widely in East Asia.
Etymology
The genus name Pseudostellaria combines the Greek prefix pseudo- ("false") with Stellaria, the related chickweed genus, reflecting its close morphological similarity to Stellaria while being distinct. The Chinese name 孩儿参属 (hái ér shēn shǔ, "children's ginseng genus") alludes to the small tuberous roots of medicinally used species such as P. heterophylla, which are used in traditional Chinese medicine.
Distribution
The genus is distributed primarily across East and North Asia, reaching the greatest species richness in China (nine species). One species, Pseudostellaria europaea, extends into Europe, and two species occur in North America. Within China, the genus is treated in Flora of China, Vol. 6 (Caryophyllaceae).
Taxonomy Notes
Pseudostellaria was described by Pax in 1934 (Nat. Pflanzenfam., ed. 2. 16c: 318). The earlier name Krascheninikovia Turczaninow ex Fenzl (1840) is a synonym, rendered illegitimate by the pre-existing Krascheninikovia Gueldenstaedt (1772). GBIF places the genus in family Caryophyllaceae, order Caryophyllales. The genus comprises approximately 18–24 species depending on authority; GBIF lists 24 descendants, while Flora of China treats about 18.
