Crossosomataceae is a small
plant
Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...
family, consisting of four
genera
Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...
of
shrub
A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...
s found only in the dry parts of the
American southwest and
Mexico
Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...
. This family has included up to ten species in the past,
although as of 2021 six species are still recognised.
''Crossosoma'' are
shrub
A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...
-like plants which can vary from being 50 cm to 5 meters tall, with small alternating leaves that surround the stem, or leaves clustered in small spurts (fascicles).
[Richardson, P. (1970). Morphology of the Crossosomataceae. I. Leaf, Stem and Node. Bulletin of the Torrey Botanical Club, 97(1), 34-39. doi:10.2307/2483988] ''Apacheria'', however, has opposite leaves.
[ ''Crossosoma'' has usually white flowers that are generally bisexual and have 5 petals attached to a nectary disk,][ but in ''Velascoa'' the flowers are campanulate and have an extremely reduced nectary disk.][
]
Genera
*'' Apacheria'' - one species, cliff brittlebush, '' Apacheria chiricahuensis''
*'' Crossosoma'' - two species, ''C. bigelovii'' and ''C. californicum''. ''C. bigelovii'' var. ''parviflora'' or ''C. parviflora'' was described for plants from the northern side of the Grand Canyon with a disjunct population in Sonora, with slightly smaller flowers than ''C. bigelovii'', but it is not recognised as distinct even at a varietal level by the ''Flora of North America'' in the 2015 volume.[
*'' Glossopetalon'' - two][ (or four species)][
*'' Velascoa'' - one species
]
References
Rosid families
Taxa named by Adolf Engler
{{Rosid-stub