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Atalaya brevialata Cowie & G.M.Wightman
SAPINDACEAE
Synonomy
Atalaya sp. Elizabeth River Cowie & G.M.Wightman
Common Name: Atalaya
Description: Suffruticose subshrub, aerial parts annual, to 45 cm tall, stems slender, to 21 cm, rootstock perennial, woody, 8-15 mm diam. Branchlets thinly pubescent, hairs stramineous, 0.1-0.3 mm long. Leaves simple, sessile, alternate, linear, 65-410 mm long, 1.4-7.5 mm wide, concolorous, intersecondary venation reticulate and prominent, with a marginal vein or intramarginal vein c. 0.5 mm from margin, both surfaces with scattered short, patent or ascending hairs to almost glabrous, base attenuate or rounded, margin entire or indistinctly crenate; apex acute, rounded, rarely spathulate. Inflorescence paniculate or sometimes corymbose, axillary, supra-axillary or terminal, to 70 mm long, stems thinly pubescent, hairs patent, short, white. Pedicels 1.5-4.5 mm long, with short patent hairs. Flowers monoecious, creamy white. Sepals 5 or 6 unequal, ovate to elliptic, widely obovate or suborbicular, 1.5-2.5 mm long, 1.5-2 mm wide, adaxial surface glabrous, abaxial surface thinly pubescent, hairs appressed to patent, short, white, margins ciliolate, apex rounded, cream to pale brown. Petals 5 or 6, oblanceolate, ovate or lanceolate, 2.5-3.5 mm long, 1.1-1.2 mm wide, adaxial surface thinly pubescent, hairs scattered, c. 0.5 mm long, weak, ascending, white, abaxial surface thinly sericeous, hairs c. 0.5 mm long, white, base attenuate and shortly clawed, margins long-ciliate; apex rounded or truncate; scales entire or shortly bilobed, suborbicular to transversely oblong, apex villous. Disc annular, entire or slightly lobed, undulate or flat. Stamens 7-9, more or less equal, 3–3.5 mm long, often exserted in male flowers; filaments 2–2.5 mm long, hairs scattered in lower 2/3, c. 0.5 mm long, weak, ascending to patent; anthers c. 1 mm long. Ovary puberulent, 3-lobed. Fruit divaricately 3-lobed, separating into indehiscent, 1-seeded samaras. Samaras 3, oblong to ovate or broadly elliptic, 11-22 mm long, 7-12 mm wide, thinly pubescent, hairs 0.1-0.5 mm long, straight to slightly arcuate, ascending to patent, hyaline to stramineous, base turgid; wing, dorsal, erect, 0.5-6 mm long; apex rounded, entire, irregular or erose, brown when mature. Seed 1, obovoid, c. 8.5 mm long, c. 8 mm wide, surface uneven but otherwise more or less smooth, pale brown.
Diagnostic Characters: Distinguished from A. variifolia, A. hemiglauca and A. salicifolia by the smaller, sericeous petals, reduced wing on the samara, the simple, linear leaves and the suffruticose growth habit.
Similar Taxa: A. variifolia, A. hemiglauca and A. salicifolia. Vegetatively, the plant is grass-like in appearance (but with pinnate venation) and may also be confused with juvenile Grevillea pteridifolia.
Whole plant (or habit)
Image: I.D. Cowie
Inflorescence
Image: I.D. Cowie
Fruit
Image: I.D. Cowie
Notes: With clear threats, only 5 subpopulations, an area of occupancy of just 4.5 hectares and an extent of occurrence of 7.6 km2, the species is regarded as threatened. The current population estimate is 302,247 ± 15,088 mature plants.

Distribution

Introduced Status: Native to NT
NT Endemic: Y
Distribution Notes: The species is known only from a small area in the Elizabeth River valley south of Darwin, in the Northern Territory.
Bioregion: Darwin Coastal

Habitat: It grows in woodland to open woodland with varying proportions of Eucalyptus tectifica and Corymbia foelscheana but also with scattered Xanthostemon paradoxus, Terminalia grandiflora and Acacia hemignosta in the overstorey with an open layer of perennial

Ecological Attributes

Flowering: Aug - November
Fruiting: November

Other Attributes

Conservation Status (TPWCA): Data Deficient
Conservation Status (EPBC): Critically Endangered
Restricted Range Taxon: Y
Etymology: The epithet brevialata means short-winged, from the Latin brevis, short, and ala, a wing, a reference to the short wing of the samara.
Flora Description Source: Unpublished notes prepared for FloraNT
Taxonomic Literature: Cowie, I.D. & Stuckey, B. (2012). Atalaya brevialata (Sapindaceae), a new species from the Northern Territory, Australia. Nuytsia 22(6): 363–370.

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