genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
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 Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
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
Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials.
Definitions of "herb" and "herbaceous"
The fourth edition of t ...
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 wide ...
s or
subshrubs
A subshrub (Latin ''suffrutex'') or dwarf shrub is a short shrub, and is a woody plant. Prostrate shrub is a related term. "Subshrub" is often used interchangeably with "bush".Jackson, Benjamin, Daydon; A Glossary of Botanic Terms with their Der ...
with alternate leaves. With the exception of species in
California
California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...
, they generally produce two types of flowers: showy, yellow
chasmogamous
Chasmogamy, is a plant reproductive mechanism in which pollination occurs in chasmogamous flowers. Chasmogamous flowers are commonly showy with open petals encircling exposed reproductive parts. Chasmogamous stems from Greek for "open marriage", na ...
(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.
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 bicknellii
''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 corymbosum
''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 dumosum
''Crocanthemum dumosum'', common names bushy frostweed and bushy rockrose, is a perennial plant that is native to the United States.
Conservation status
It is listed as endangered in Rhode Island, threatened in New York, a species of special c ...
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* ''
Crocanthemum georgianum
''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 glomeratum
''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 greenei
''Crocanthemum greenei'' is a rare species of flowering plant in the rock-rose family known by the common name island rush-rose. It is endemic to the Channel Islands of California, where it grows in the chaparral of the rocky seaside slopes. It ...
''
* ''
Crocanthemum nashii
''Crocanthemum nashii'' is a species of plant endemic to Florida and other parts of the southeastern United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country p ...
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* ''
Crocanthemum nutans
''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 propinquum
''Helianthemum propinquum'', formerly called ''Crocanthemum propinquum'', common names low frostweed and low rockrose, is a perennial plant that is native to the United States.
Conservation status
It is listed as endangered in Connecticut, and ...
''
* ''
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 ...