Petrosaviaceae is a
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 ...
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 belonging to a
monotypic
In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...
order, Petrosaviales. Petrosaviales are
monocots
Monocotyledons (), commonly referred to as monocots, ( Lilianae '' sensu'' Chase & Reveal) are grass and grass-like flowering plants (angiosperms), the seeds of which typically contain only one embryonic leaf, or cotyledon. They constitute one of ...
, and are grouped within the
lilioid monocots. Petrosaviales are a very small order (one family, two genera and four species were accepted in 2016
) of photosynthetic (''
Japonolirion'') and rare leafless achlorophyllous,
mycoheterotrophic
Myco-heterotrophy (from Greek μύκης , "fungus", ἕτερος ', "another", "different" and τροφή ', "nutrition") is a symbiotic relationship between certain kinds of plants and fungi, in which the plant gets all or part of its food fro ...
plants (''
Petrosavia'') found in dark
montane
Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures fall as elevation increases, causing the ecosystem to stratify. This stratification is a crucial ...
rainforests
Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainforest ...
in Japan, China, Southeast Asia and Borneo. They are characterised by having
bracteate
racemes
A raceme ( or ) or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the s ...
,
pedicellate flowers, six persistent tepals,
septal nectaries, three almost distinct
carpels, simultaneous
microsporogenesis,
monosulcate
Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophy ...
pollen, and
follicular fruit.
Taxonomy
The family has only been recognized in modern classifications, previously the plants involved were usually treated as belonging to the family
Liliaceae
The lily family, Liliaceae, consists of about 15 genera and 610 species of flowering plants within the order Liliales. They are monocotyledonous, perennial, herbaceous, often bulbous geophytes. Plants in this family have evolved with a fair a ...
. The
APG II system
The APG II system (Angiosperm Phylogeny Group II system) of plant classification is the second, now obsolete, version of a modern, mostly molecular-based, system of plant taxonomy that was published in April 2003 by the Angiosperm Phylogeny Gr ...
recognized the family and assigned it to the clade
monocots
Monocotyledons (), commonly referred to as monocots, ( Lilianae '' sensu'' Chase & Reveal) are grass and grass-like flowering plants (angiosperms), the seeds of which typically contain only one embryonic leaf, or cotyledon. They constitute one of ...
, unplaced as to order. The
APG III system of 2009 and the
APG IV system
The APG IV system of flowering plant classification is the fourth version of a modern, mostly molecular-based, system of plant taxonomy for flowering plants (angiosperms) being developed by the Angiosperm Phylogeny Group (APG). It was published ...
of 2016 placed family Petrosaviaceae in order Petrosaviales.
Genera
, two genera are accepted by the World Checklist of Selected Plant Families
The World Checklist of Selected Plant Families (usually abbreviated to WCSP) is an "international collaborative programme that provides the latest peer reviewed and published opinions on the accepted scientific names and synonyms of selected pla ...
:
Distribution and habitat
The plants in both genera are found in high-elevation habitats.
References
Bibliography
*
External links
''Petrosavia'' in ''Flora of China''
links at CSDL, Texas
The Plant List
*
*
{{Taxonbar, from=Q131296
Monocot families
Petrosaviales