genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
of
flowering plant
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...
s in the
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
Cistaceae
The Cistaceae are a small family of plants (rock-rose or rock rose family) known for their beautiful shrubs, which are profusely covered by flowers at the time of blossom. This family consists of about 170(-200) species in nine genera that are ...
. They are native to both North and South America where they are widespread. The common name frostweed relates to the ice crystals which form from sap exuding from cracks near the base of the stem in the late fall.
''Crocanthemum'' are herbaceous
perennial
A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wid ...
s or subshrubs with alternate leaves. With the exception of species in
California
California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
, they generally produce two types of flowers: showy, yellow chasmogamous (cross-pollinated) produced earlier in the growing season, followed by
cleistogamous
Cleistogamy is a type of automatic self-pollination of certain plants that can propagate by using non-opening, self-pollinating flowers. Especially well known in peanuts, peas, and pansies, this behavior is most widespread in the grass family. How ...
(self-pollinated) flowers that are smaller and lack petals. All species of ''Crocanthemum'' are fire tolerant and are found in open habitats.
Although the genus was first named in 1836 to encompass New World species of ''
Helianthemum
''Helianthemum'' , known as rock rose, sunrose, rushrose, or frostweed,' ...
'', it generally went unrecognized by taxonomists and its species were included in a broad concept of ''Helianthemum'' throughout much of the 1800s and 1900s. However, phylogenetic studies in 2004 and 2009 indicated that the New World species of ''Helianthemum'' were more closely related to ''
Hudsonia
''Hudsonia'' (goldenheather, poverty grass) is a small genus of three species of flowering plants in the family Cistaceae, native to North America. They are typical of sand dune habitats.
They are evergreen subshrubs growing to 20 cm tall ...
'' than Old World ''Helianthemum''. This required the resurrection of the genus ''Crocanthemum'' in order to maintain monophyly.
Species
* ''
Crocanthemum aldersonii
''Crocanthemum'' is a genus of flowering plants in the family Cistaceae. They are native to both North and South America where they are widespread. The common name frostweed relates to the ice crystals which form from sap exuding from cracks near ...
''
* ''
Crocanthemum arenicola
''Crocanthemum'' is a genus of flowering plants in the family Cistaceae. They are native to both North and South America where they are widespread. The common name frostweed relates to the ice crystals which form from sap exuding from cracks near ...
''
* ''
Crocanthemum argenteum
''Crocanthemum'' is a genus of flowering plants in the family Cistaceae. They are native to both North and South America where they are widespread. The common name frostweed relates to the ice crystals which form from sap exuding from cracks near ...
Crocanthemum brasiliense
''Crocanthemum'' is a genus of flowering plants in the family Cistaceae. They are native to both North and South America where they are widespread. The common name frostweed relates to the ice crystals which form from sap exuding from cracks near ...
Crocanthemum carolinianum
''Crocanthemum'' is a genus of flowering plants in the family Cistaceae. They are native to both North and South America where they are widespread. The common name frostweed relates to the ice crystals which form from sap exuding from cracks near ...
Crocanthemum pringlei
''Crocanthemum'' is a genus of flowering plants in the family Cistaceae. They are native to both North and South America where they are widespread. The common name frostweed relates to the ice crystals which form from sap exuding from cracks near ...
Crocanthemum rosmarinifolium
''Crocanthemum'' is a genus of flowering plants in the family Cistaceae. They are native to both North and South America where they are widespread. The common name frostweed relates to the ice crystals which form from sap exuding from cracks near ...