Geleznowia eximia K.A.Sheph. & A.D.Crawford, 2023

Anderson, Benjamin M., Binks, Rachel M., Byrne, Margaret, Crawford, Andrew D. & Shepherd, Kelly A., 2023, Using RADseq to resolve species boundaries in a morphologically complex group of yellow-flowered shrubs (Geleznowia, Rutaceae), Australian Systematic Botany 36 (4), pp. 277-311 : 298-299

Geleznowia eximia K.A.Sheph. & A.D.Crawford , sp. nov.

Type: Western Australia, Brand Highway [North of Geraldton] [precise locality withheld for conservation reasons], 10 Sep. 2008, A. Crawford ADC 1844 (holo: PERTH 08298858 ) .

Erect single-stemmed shrub up to 0.6–0.75 m high; older branches light brown to light grey–brown and glabrous, younger branches yellowish-green with an indumentum of moderately dense, simple hairs to 0.2–0.25 mm long. Leaves silvery grey–green to green, elliptic to obovate, 5.3–8.5 mm long, 2.8–6 mm wide, adaxial surface slightly concave and glabrous or minutely scabrous with scattered hairs <0.05 mm long, abaxial surface glandular–verrucose, glabrous or minutely scabrous with scattered hairs <0.05 mm long. Flowers 5–7, vivid golden-yellow, terminal inflorescences 16–25 mm long. Pedicel central flower up to 4.5 mm long, with dense hairs up to 0.5 mm long. Bracts 6–7, vivid yellow, obovate to broadly obovate sometimes with an attenuate base, 10.2–16 mm long, 6.4–10 mm wide; adaxial surface glabrous or with scattered hairs up to 0.05–0.2 mm long; abaxial surface faintly glandular–verrucose, glabrous or with scattered hairs 0.05 mm long. Bracteoles 10 usually paired below each flower except central flower, elliptic to obovate, 3.5–10.2 mm long, 4–5.2 mm wide, adaxial surface glabrous or with scattered to moderately dense hairs 0.05–0.3 mm long; abaxial surface glabrous or with scattered hairs up to 0.1 mm long. Sepals yellow, oblong to broadly obovate, longer than petals, 10.6–12.2 mm long, 6–7.6 mm wide, glabrous or with scattered hairs up to 0.1 mm long. Petals deep yellow, elliptic, cupped, coriaceous, 6.6–7 mm long, 2.3–3 mm wide, glabrous. Stamens 10; filaments 3–3.4 mm long, broadening at base up to 0.4–0.6 mm wide, glabrous; anthers oblong, 1.5–1.8 mm long, 0.6–0.8 mm wide. Carpels 5, free, with 2 ovules per carpel, total length 2.6 mm, total width 2.8 mm, verrucose, glabrous or with scattered hairs up to 0.05 mm long. Style glabrous, 3.3–5.3 mm long, 0.3 mm wide; stigma obovoid, 0.3 mm long, 0.4–0.5 mm wide. Fruit obovoid, 8 mm long, 9.5 mm wide. Seeds dark brown to black, 3.8–5.0 mm long, 2.4–3.3 mm wide, aril pale cream 2.1–2.9 mm long ( Fig. 1 e , 11 ).

Distribution and habitat

Known only from one location ( Fig. 8 ). Found growing in deep yellow sand in low shrubland with Grevillea , Acacia , Hibbertia and Conospermum .

Phenology

Flowering specimens collected in September and October, with fruits forming in late October.

Conservation status

This species is currently known only from a single population with two extant plants. As such, it is likely to meet criteria for listing as Threatened (Critically Endangered); however, further survey is urgently needed to confirm this. It is to be listed as Priority One under Conservation Codes for Western Australian Flora ( T. Llorens, pers. comm.).

Etymology

From the Latin eximius, meaning exceptional or uncommon, in reference to the attractiveness and rarity of this new species.

Notes

Geleznowia eximia can be recognised within the genus by the following combination of characters: a shrub 0.6–0.75 m high with silvery grey–green to green leaves; 5–7 flowers per inflorescence, surrounded by 6 or 7 vivid yellow petaloid bracts, 10.2–16 mm long, 6.4–10 mm wide, abaxial surface glabrous or with scattered hairs 0.05 mm long; 10 bracteoles; sepals 10.6–12.2 mm long, 6–7.6 mm wide; and a broad stigma 0.4–0.5 mm wide. For comparison, see notes under G. amabilis .

Selected specimens examined

WESTERN AUSTRALIA. [localities withheld for conservation reasons] 23 Aug. 1997, P. G. Armstrong s.n. ( PERTH 05982073 ); 3 Oct. 2004, A. Crawford ADC 588 ( PERTH 07118252 ); 28 Aug. 2020, D. Growns DGRO 162 ( MEL, PERTH 09508724 ); 21 July 2004, M. Harding 2 ( PERTH 06947956 ); 31 Aug. 2021, K. A. Shepherd & B. M. Anderson KS 1832 ( PERTH 09507949 ); 31 Aug.2021, K. A. Shepherd & B. M. Anderson KS 1833 ( PERTH 09507930 ) .

Figures

Fig. 1. (Caption on next page)

Fig. 11. Geleznowia eximia: (a) habitat; (b) habit; (c) flowering stem showing yellowish-green stems and whorls of green leaves; (d) dense flowering heads with up to six flowers; (e) open flower showing broad petals and sepals and style with a distinct obovoid stigma at the apex. Vouchers: K.A. Shepherd & B.M. Anderson KS 1832 and KS 1833 (PERTH). Photos: K. A. Shepherd.

Fig. 8. Distributions of all seven Geleznowia species in Western Australia. The base map is sourced from GADM (ver. 3.6, see https://gadm.org), with grey borders showing IBRA regions and subregions (Department of Agriculture, Water and the Environment 2020).