Commersonia amystia C.F.Wilkins & L.M.Copel. APNI*
Synonyms: Rulingia amystia APNI*
Description: Dwarf shrub, 10–30 cm high, prostrate to decumbent. Branchlets densely hairy, with sessile, white, stellate hairs with 4–6 erect arms. Stipules late caducous, green throughout, or with red apex, ovate-lanceolate to narrow-lanceolate, rarely bifid, 0.8–4.5 long, 0.3–1.5 mm wide, adaxial surface with sparse, appressed, white, stellate hairs with 1 or 2 arms.
Mature leaf with petiole 0.8–2.5 mm long, hairs as on distal branchlets; blade scarcely discolorous, mid green over pale green, narrow-ovate, rarely ovate, 2.5–31.9 mm long, 1.5–9.2 mm wide, base cordate, scarcely oblique; abaxial surface densely hairy to tomentose, hairs sessile, white, stellate with c. 6 erect arms; adaxial surface moderately hairy, with hairs sessile, white, stellate, with 1–8 erect arms; margin sinuate or irregularly serrate, recurved, hence appearing entire, flat or undulate, apex obtuse or acute. Juvenile leaves trilobed, serrulate, up to 53 mm long, 31 mm wide.
Inflorescence a leaf-opposed cyme, 9–39 mm long, flowers 1–6. Peduncle 2.5–18 mm long, extending to 10–31 mm with fruit; pedicel 2–8.5 mm long; both peduncle and pedicel densely hairy, hairs sessile, white, stellate, with c. 6 erect arms. Calyx white becoming pale pink, 3.9–5.8 mm long, petals white, 1.8–3.2 mm long. Staminodes five, one inserted between each stamen. Anthers dark red.
Capsule sub-globose, or ellipsoid, red-brown, wings absent, 5.5–6 mm long, c. 7 mm wide with dense soft white stellate hairs.
Flowering: Flowers in August, September and October with young fruits usually forming in October and November.
Distribution and occurrence: Currently known from two populations in the Inverell district of northern New South Wales and three populations in the Ballandean – Stanthorpe districts of southern Queensland.
Grows in skeletal, sandy-loams amongst crevices of granitic and acid volcanic outcrops. Altitude ranges from 700 m to approximately 1050 m. Associated species include Eucalyptus prava, Harmogia densifolia, Acacia triptera, Homoranthus prolixus, Lepidosperma laterale, Actinotus gibbonsii and Cheilanthes sieberi. Commersonia amystia appears to be an obligate seeder that is killed by fire but germinates in abundance shortly thereafter. At the type locality hundreds of plants were
NSW subdivisions: NT, NWS
Other Australian states: Qld
Conservation status: the species is currently known from fewer than 300 individuals in New South Wales and an unknown number of plants in southern Queensland. The only reserved population is in Single National Park where approximately 30 plants are known from a single rocky outcrop. Threats to Commersonia amystia include an inappropriate fire regime, grazing by feral goats and disturbance by feral pigs. Comparison with similar species: Commersonia amystia appears to be most closely related to Rulingia rugosa in having hairy filaments, the lower surface of the leaves with a similar tomentose surface rather than dense hairs as observed in R. dasyphylla, and in having large fruits with dense, simple hairs on long setae. It differs from R. rugosa in having smooth, thin, pale green leaves, rather than rugose, mid green leaves, (1)2- 4(6) flowers per inflorescence rather than 7–15, and a petal base that is obovate when flattened and strongly gibbous below and above its basal attachment, rather than ovate and gibbous only above the attachment.
Text by Louisa Murray
Taxon concept: Telopea 12 (1): 2008, pages 60-63
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