Glossopetalon spinescens

It is native to Mexico and the western United States, where it grows in mountainous habitats, often on limestone substrates.

[11] This shrub forms a dense, erect clump of many thin, branching, thorny stems approaching 3 metres (9.8 ft) in maximum height.

[7] Glossopetalon spinescens was described by the American botanist Asa Gray in 1853, based on a specimen collected by Charles Wright in 1852 in a mountain ravine near a location called 'Frontera', in either New Mexico or Texas.

It found that G. spinescens was largely split into two main geographic lineages: a northwest one and a southeast one.

The taxa G. clokeyi and G. texense were found to belong to either lineage respectively, and could therefore no longer parsimoniously be seen as distinct species.

[7] In the US it occurs, from north to south and west to east, in the states of Washington, Idaho, Montana, Oregon, Wyoming, California, Nevada, Utah, Colorado, Arizona, New Mexico, Oklahoma and Texas.

[7] It grows on hillsides, rocky slopes and crevices and ledges of cliffs in canyons and outcrops in desert scrub, grasslands, chaparral and juniper woodland habitats.

Glossopetalon spinescens in the White Mountains , Nevada, 1715m (5620ft) elevation in early May. The flowers are pollinated and beginning to fruit, but not all the petals have been shed. Dehiscent, persistent follicles can be seen from the previous year. The leaves have largely been shed. The tips of the stems are beginning to die off; their sharp, tapered, hardened ends function as spines.