Asagraea spinosa (A.Gray) Baill.
Dalea spinosa A.Gray
Parosela spinosa (A.Gray) A.Heller
Psorodendron spinosum (A.Gray) Rydb.
Psorothamnus spinosus is a spiny shrub or a small, round-headed tree, usually floweing as a bushy shrub when around 1.5 metres tall but eventually reaching 7 metres, exceptionally to 10 metres. One to a few main trunks up to 10cm in diameter are formed[
The plant is harvested from the wild for local use as a source of wood.
Southwestern N. America - Nevada, southern California, Arizona, northern Mexico (Baja Norte, northern Sonora)
Sandy and rocky washes amongst Larrea scrub; usually at elevations below 240 metres, but up to 430 metres in the south of its range[
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Psorothamnus spinosus is native to the semi-arid and arid regions of southwestern N. America.
The adult plant only produces leaves after rain has fallen in the cool season. These leaves are small and do not remain more than 3 months - the tree is leafless for most of the year, photosynthesis being carried out by the young, green shoots of the current years growth[
The tree is fast growing and short-lived (especially considering its arid environment), reaching full size in just a few years and perishing early[
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[
The brownish-grey heartwood is conspicuously variegated with brown stripes. The wood is hard and close-grained. An attractive wood that is easy to work and finishes well, it is considered to be desirable for decorative articles but is usually only available in small amounts[
The wood is used for fuel, burning well and giving off an aromatic smoke[
Seed - it has a hard seedcoat and benefits from scarification before sowing in order to speed up and improve germination[
]. This can usually be done by pouring a small amount of nearly boiling water on the seeds (being careful not to cook them!) and then soaking them for 12 - 24 hours in warm water. By this time they should have imbibed moisture and swollen - if they have not, then carefully make a nick in the seedcoat (being careful not to damage the embryo) and soak for a further 12 hours before sowing.