''Alloteropsis semialata'', known commonly as black seed grass, cockatoo grass, ''donkersaad gras'', ''swartsaadgras'', ''tweevingergras'', and ''isi quinti'', is a

perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...

grass found in tropical regions of Asia, Africa,

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

, and

Australasia Australasia is a subregion of Oceania, comprising Australia, New Zealand (overlapping with Polynesia), and sometimes including New Guinea and surrounding islands (overlapping with Melanesia). The term is used in a number of different context ...

Description

This plant typically reaches tall, growing from a short, white

rhizome In botany and dendrology, a rhizome ( ) is a modified subterranean plant stem that sends out roots and Shoot (botany), shoots from its Node (botany), nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from ...

. The leaf blades are typically long and wide. The plant produces 2-flowered fertile spikelets.

Etymology

The genus name '' Allopteropsis'' comes from the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

words "allotrios", meaning "belonging to another", and "opsis", meaning appearance. The specific epithet ''semialata'' comes from the

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

"semi" (half) and "ala" (wing), referring to the winged margins of the upper

glume In botany, a glume is a bract (leaf-like structure) below a spikelet in the inflorescence (flower cluster) of grass Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family (biology), family of monocotyledonous flow ...

Variation

The species has two

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

including ''A. semialata'' subsp. ''semialata'', which uses the C4 photosynthetic pathway, and ''A. semialata'' subsp. ''eckloniana'', which uses the C3 photosynthetic pathway. As the only plant species known to use both pathways, it is an important model for the study of the evolution of

photosynthesis Photosynthesis ( ) is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabo ...

. There are a wide range of intermediate phenotypes, including that of C2 photosynthesis. The species has been found in a

polyploid Polyploidy is a condition in which the biological cell, cells of an organism have more than two paired sets of (Homologous chromosome, homologous) chromosomes. Most species whose cells have Cell nucleus, nuclei (eukaryotes) are diploid, meaning ...

series with

diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Here ''sets of chromosomes'' refers to the number of maternal and paternal chromosome copies, ...

tetraploid Polyploidy is a condition in which the cells of an organism have more than two paired sets of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two complete sets of chromosomes, one fro ...

hexaploid Polyploidy is a condition in which the cells of an organism have more than two paired sets of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two complete sets of chromosomes, one fro ...

octoploid Polyploidy is a condition in which the cells of an organism have more than two paired sets of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two complete sets of chromosomes, one fro ...

and dodecaploid individuals. All members of the C3 subspecies are diploid and there are no diploid individuals outside of that subspecies.

Distribution and habitat

It is distributed across much of

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

and

subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones immediately to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Ge ...

Asia, Africa,

, Australia, and

Papuasia Papuasia is a Level 2 botanical region defined in the World Geographical Scheme for Recording Plant Distributions (WGSRPD). It lies in the southwestern Pacific Ocean, in the Melanesia ecoregion of Oceania and Tropical Asia. It comprises th ...

.Hitchcock, A. S. 1909. Catalogue of the Grasses of Cuba. Contributions from the United States National Herbarium 12(6): 183–258, vii–xi
/ref>

Ecology

The seeds of this species are an important component of the wet-season diet of many granivorous finches and parrots. The rhizomes are part of the dry-season diet of some animals.

References

Panicoideae Flora of Africa Flora of Asia {{Panicoideae-stub