The following is a very incomplete listing of manzanitas found in the desert southwest of the US (based on the photos I currently have in hand):
Bigberry Manzanita, Big Berry Manzanita: Arctostaphylos glauca (Synonyms: Arctostaphylos glauca var. eremicola; Arctostaphylos glauca var. puberula; Xerobotrys glaucus)
Pointleaf Manzanita: Arctostaphylos pungens (Synonyms: Arctostaphylos chaloneorum, Arctostaphylos pseudopungens, Arctostaphylos pungens ssp. chaloneorum)