Acacia midgleyi M.W.McDonald & Maslin, Austral. Syst. Bot. 13(1): 61, figs. 19 & 20 (2000)
Cape York Salwood
Trees 8–25 m tall, single-stemmed or sparingly divided near ground level, trunks on oldest plants to 60 (–90) cm diam. Bark hard and shallowly rimose. Branchlets subterete, glabrous. Juvenile phyllodes highly glossy. Phyllodes dimidiate to subfalcate, sometimes falcate, 8–12.5 (–16.5) cm long, (0.8–) 1–3.5 (–4.2) cm wide, glabrous, milky green when dry; longitudinal nerves numerous, parallel and very closely-spaced (5–10 per mm), +/- touching; pulvinus 4–10 mm long. Gland basal, not prominent. Inflorescences simple, 2–4 per axil; peduncles 3–10 mm long, glabrous; spikes 3–7 cm long, interrupted, pale yellow (almost cream) to lemon yellow. Flowers 5-merous; calyx gamosepalous, shallowly dissected; ovary glabrous or sparsely hairy. Pods narrowly oblong, flat or 1–3 times spirally twisted, +/- straight, 5–12 cm long, 1–2 (–2.5) cm wide, dehiscing along ventral suture, crustose, resinous, +/- transversely nerved, nerves not prominently raised. Seeds +/- transverse, ovoid, ellipsoid or obovoid, 4–7 mm long, 2–4 mm wide, glossy, black; funicle/aril many-folded, 3–10 mm long (unextended), creamy-grey or greyish (aging pale yellow).
Endemic to Cape York Peninsula, Qld, where it extends from the Coleman River north to the Wenlock-Olive Rivers region. It is most common on the uplands of the eastern side of Cape York Peninsula. Occurs along river banks, seasonal drainage systems and is a component of rainforests in the region.
Adult phyllodes show considerable variation in dimensions both within and between populations.
Plants from Stanley Island, a continental island near Bathurst Head, resemble A. midgleyi in having similar phyllode nervation, however, further field collections are required to assess their status.
Acacia midgleyi is a member of the ‘ A. aulacocarpa group’ and until recently was included within A. aulacocarpa . Its carpological characters show A. midgleyi as being most closely related to A. crassicarpa , A. lamprocarpa and especially to the New Guinea endemic, A. peregrina . Acacia midgleyi is distinguished from these relatives by the following combination of characters: seedling phyllodes highly glossy, adult phyllodes pale green (when dry) and with closely spaced minor nerves (i.e. 5–10 nerves per mm) which appear to lack an internerve space on dried specimens, spikes 2–4 per axil and 3–7 cm long, ovary normally glabrous, pods crustose and funicle/aril creamy-grey or greyish, many-folded and 3–10 mm long when unextended. A revision of the ‘ A. aulacocarpa group’ is presented in M.W.McDonald & B.R.Maslin, Austral. Syst. Bot. 13(1): 21–78 (2000). Acacia midgleyi is sometimes sympatric with, and superficially resembles, A. polystachya which is readily distinguished by its narrower pods, yellow funicle/aril encircling the seeds and phyllodes which have 2 of the main nerves running together along the midline near the base
Acacia midgleyi has commercial potential as a forestry plantation species on sites where A. peregrina and A. crassicarpa perform well, however, it is likely that its success as a plantation species will depend on comprehensive provenance trials as natural stands exhibit considerable variation in habit.
Type of accepted name
15 km north of Pascoe River crossing along Portland Roads Road, Qld, 16 Oct. 1996, M.W.McDonald 2255 & P.A.Butcher; holo: PERTH; iso: BRI, CANB, K, NSW.
M.W.McDonald & B.R.Maslin, Austral. Syst. Bot. 13: 64, fig. 19 & 65, fig. 20 (2000).
Qld: 11 km E of Aurukun, J.R.Clarkson 4515 (DNA, K, MEL, MO, PERTH, QRS); Myall Creek, 53.8 km E of Weipa along Weipa–Coen Road, M.W.McDonald 2231 & P.A.Butcher (BRI, NSW, PERTH); 1.7 km N of Tozers Gap along Portland Roads Road, Iron Range National Park, M.W.McDonald 2254 & P.A.Butcher (BRI, CANB, NSW, PERTH); Cape York Peninsula, Wenlock River crossing on Coen–Bamaga Road (71 km N of Weipa turnoff), M.W.McDonald & B.R.Maslin BRM 7652 (CANB, BRI, NSW, PERTH); McIlwraith Range, 28.9 km E along Leo Creek Mine track, M.W.McDonald 2350 & T.K.Vercoe (BRI, CANB, K, NSW, PERTH).
This species was not included in the Fl. Australia treatment of Acacia . The above account is based on the original description.