Psorothamnus

Psorothamnus is a genus of plants in the legume family. These are shrubs and small trees. Many are known by the general common name indigo bush. Some are referred to as daleas, as this genus was once included in genus Dalea. These are generally thorny, thickly branched, strongly scented bushes. Most species bear lupinlike raceme inflorescences of bright purple legume flowers and gland-rich pods. Psorothamnus species are native to the southwestern United States and northern Mexico.

Psorothamnus
Psorothamnus fremontii
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Rosids
Order:	Fabales
Family:	Fabaceae
Subfamily:	Faboideae
Tribe:	Amorpheae
Genus:	Psorothamnus Rydb.
Type species
Psorothamnus emoryi (A.Gray) Rydb.
Species[1]
4; see text
Synonyms[1]
Asagraea Baill.

The genus formerly included additional species, but was found to be paraphyletic, and genus Psorodendron was reinstated to accommodate sections Xylodalea, Capnodendron, and Winnemucca.^[2][3]

Species

Four species are currently accepted.^[4]

• Psorothamnus emoryi (A. Gray) Rydb. – dyebush, Emory's indigo bush
• Psorothamnus polydenius (S. Watson) Rydb. – Nevada dalea
• Psorothamnus scoparius (A. Gray) Rydb. – broom dalea
• Psorothamnus thompsoniae (Vail) S.L. Welsh & N.D. Atwood – Thompson's dalea

Formerly placed here

• Psorodendron arborescens (Torr. ex A.Gray) Rydb., as Psorothamnus arborescens (A. Gray) Barneby
• Psorodendron fremontii (Torr. ex A.Gray) Rydb., as Psorothamnus fremontii (A. Gray) Barneby
• Psorodendron kingii (S.Watson) Rydb., as Psorothamnus kingii (S. Watson) Barneby
• Psorodendron schottii (Torr.) Rydb., as Psorothamnus schottii (Torr.) Barneby
• Psorodendron spinosum (A.Gray) Rydb., as Psorothamnus spinosus (A. Gray) Barneby