''Xyris'' is a
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, the yelloweyed grasses, in the
yellow-eyed-grass family. The genus counts over 250 species, widespread over much of the world, with the center of distribution in the
Guianas
The Guianas, sometimes called by the Spanish loan-word ''Guayanas'' (''Las Guayanas''), is a region in north-eastern South America which includes the following three territories:
* French Guiana, an overseas department and region of France
* ...
.
[Kew World Checklist of Selected Plant Families]
/ref>[Flora of China, Vol. 24 Page 4, 黄眼草属 huang yan cao shu, ''Xyris'' Linnaeus, Sp. Pl. 1: 42. 1753; Gen. Pl. ed. 5; 25, 1754. ]
/ref>
The leaves
A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...
are mostly distichous
In botany, phyllotaxis () or phyllotaxy is the arrangement of leaves on a plant stem. Phyllotactic spirals form a distinctive class of patterns in nature.
Leaf arrangement
The basic arrangements of leaves on a stem are opposite and alternat ...
, linear, flat, and thin or round with a conspicuous sheath at the base. They are arranged in a basal aggregation. The small, yellow flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...
s are borne on a spherical or cylindrical spike
Spike, spikes, or spiking may refer to:
Arts, entertainment, and media
Books
* ''The Spike'' (novel), a novel by Arnaud de Borchgrave
* ''The Spike'' (book), a nonfiction book by Damien Broderick
* ''The Spike'', a starship in Peter F. Hamilto ...
or head
A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste. Some very simple animals may ...
(inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...
). Each flower grows from the axil of a leathery bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of ...
. The fruit
In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering.
Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...
is a nonfleshy, dehiscent
Dehiscence is the splitting of a mature plant structure along a built-in line of weakness to release its contents. This is common among fruits, anthers and sporangia. Sometimes this involves the complete detachment of a part; structures that op ...
capsule. In ''Xyris complanata'', a single flower bud on the spike appears in the morning, and expands into a conspicuous flower during the afternoon hours.[
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 publishe ...
, of 2016, places the genus in family Xyridaceae
The Xyridaceae are a family of flowering plants. This family has been recognized by many taxonomists and is known as the yellow-eyed grass family.
The APG II system, of 2003 (unchanged from the APG system of 1998), also recognizes this family, ...
, into the order Poales
The Poales are a large order of flowering plants in the monocotyledons, and includes families of plants such as the grasses, bromeliads, and sedges. Sixteen plant families are currently recognized by botanists to be part of Poales.
Descriptio ...
in the clade commelinids
In plant taxonomy, commelinids (originally commelinoids) (plural, not capitalised) is a clade of flowering plants within the monocots, distinguished by having cell walls containing ferulic acid.
The commelinids are the only clade that the APG IV ...
, in the 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 t ...
.
Species include:
References
External links
''Xyris'' in the ''Flora of North America''
{{Authority control
Poales genera