Aira

Aira is a genus of annual grasses. They are grass plants with ornamental importance, due to the shape of their inflorescences. It comprises 348 described species and of these, only 9 accepted.

One of its common names, shared with its similar and related genera Deschampsia and Koeleria, is pasto pelo, due to its leaves and very thin stems.

The species is typically found on dry sandy sites, growing to 20-40 cm tall.

Description

They are annual plants. Leaves with sheaths with free margins; ligule lanceolate, acute, membranous; limb slender, convoluted on desiccation. Inflorescence in a lax panicle, with bare branches at the base. Spikelets slightly compressed laterally, with 2 hermaphroditic flowers; glabrous rachilla. Glumes subequal, slightly keeled; the lower single-veined, the upper three-veined. Rachilla not prolonged above the flower. Lemma lanceolate, with 5 slightly marked veins, briefly forked; dorsal ridge inserted below middle of lemma, geniculate. Callus orbicularis, briefly hirsute. Palea somewhat shorter than the lemma, with 2 keels, bidentate. Lodicule with 1 lateral tooth. Ovary glabrous. Oblongoid caryopsis, not furrowed, adherent to the palea and the lemma. Point thread.

Taxonomy

The genus was described by Carlos Linnaeus and published in Species Plantarum 1: 63–66. 1753. The type species is: Aira praecox L.

Etymology

Aira: generic name that takes the Greek name of Lolium temulentum.

Accepted species

The following is a list of the species of the genus Aira accepted up to July 2011, arranged alphabetically. For each one, the binomial name followed by the author is indicated, abbreviated according to conventions and uses.

• Aira caryophyllea L.
• Aira cupaniana Guss.
• Aira elegantissima Schur
• Aira × hybrida Gaudich.
• Aira praecox L.
• Aira provincialis
• Aira scoparia Adamovic
• Aira tenorei
• Aira uniaristata Cav.

Uses

Several highly ornamental species are also used in dried flower arrangements.