Berlandiera is a genus of about 10–15 perennial herbs and subshrubs in the family Asteraceae (order Asterales), native to the south-central and southwestern United States and northern Mexico. The genus was described by Augustin Pyramus de Candolle in 1836 and named in honour of the Swiss-Belgian naturalist and explorer Jean-Louis Berlandier (1803–1851), who collected widely in Texas and Mexico.
Plants are typically 8–120 cm tall, with stems that often arise annually from persistent taproots or woody caudices. The herbage is usually rough or soft-hairy — hirsute, hispid, scabrous, or velvety. Leaves are alternate, basal and/or cauline, and vary considerably in blade shape: elongate-deltate, lanceolate, lyrate, oblanceolate, oblong, or spatulate, often with pinnately lobed margins. The flower heads are radiate and borne singly or in paniculiform to corymbiform arrays. Each head has (2–)8(–13) ray florets with pale yellow to orange-yellow petals whose undersides are green, red, or maroon — or marked with 9–12 anastomosing coloured veins — giving rise to the common name greeneyes. The disc florets number 80–200+ and are functionally staminate. The fruit is a black cypsela (achene) that is distinctive in being shed still attached to two adjacent paleae, two disc florets, and a subtending phyllary as a unit.
All species share a chromosome base of x = 15 (2n = 30) and are intercrossable in cultivation. The most widely cultivated species is Berlandiera lyrata, the chocolate flower, noted for its strong chocolate scent in the morning. Other species in the genus include B. betonicifolia, B. subacaulis, B. pumila, and B. texana.
Etymology
The genus name Berlandiera honours Jean-Louis Berlandier (1803–1851), a Swiss-Belgian naturalist, botanist, and explorer who collected plants extensively in Texas and northeastern Mexico during the early 19th century. The genus was formally described by the Swiss botanist Augustin Pyramus de Candolle in 1836.
Distribution
Berlandiera occurs across the south-central and southwestern United States — including Texas, Oklahoma, Kansas, New Mexico, Arizona, Colorado, Missouri, and the southeastern states — and extends into northeastern, northwestern, and southwestern Mexico. The centre of diversity lies in Texas and adjacent regions.
Ecology
Species grow in prairies, grasslands, open woodlands, roadsides, and disturbed ground across arid to semi-arid regions. Plants are adapted to drought through their deep taproots and woody caudices, and they thrive in full sun on well-drained soils. The chromosome uniformity (2n = 30) and broad intercrossability among species suggests active hybridisation where ranges overlap.
