Acianthus exiguus D.L.Jones APNI*
Synonyms: Acianthus scopulus D.L.Jones APNI*
Acianthus sp. aff. fornicatus (Tathra) APNI*
Acianthus sp. A sensu Harden (1993) APNI*
Description: Terrestrial herb.
Leaf 18–30 mm long, 15–20 mm wide, upper surface dark green, lower surface light reddish purple.
Raceme 6–10 cm high, 1–5-flowered. Flowers 5–7 mm long, translucent, greenish white with a pink and green labellum. Dorsal sepal ovate to elliptic, cucullate, 4–5 mm long, 3–3.3 mm wide. Lateral sepals linear to lanceolate, 6–7 mm long, 0.6–0.8 mm wide, with a faint red central stripe; apical point c. 1.5 mm long. Petals narrow-ovate to lanceolate, 2–2.5 mm long, 0.7–0.8 mm wide, translucent. Labellum oblong to elliptic, margins not revolute, entire, 3.5–4 mm long, 1.8–2 mm wide, pink; callus thick, fleshy, green, papillose near the apex.
Distribution and occurrence: Grows in moist areas of tall sclerophyll forest and littoral rainforest; uncommon.
NSW subdivisions: NC, SC
When Acianthus scopulus was described, it was compared with A. fornicatus, and not with A. exiguus to which it is identical except for the presence of two small 'fang-like' appendages at the distal end of the stigma. Based on collections in NSW A. exiguus occurs in coast and ranges of northern New South Wales, and is likely more widely distributed than currently appreciated. The full extent of the distribution of A. exiguus and the significance of variation in column morphology both require further investigation before segregation of the plants from Tathra as a separate species can be justified.
Text by D. L. Jones, distribution and synonymy updated (21 Oct 2020), and notes (4 Feb 2021) by Matt A.M. Renner.
Taxon concept: Flora of NSW 4 (1993)
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