Aglaia fellii W.E.Cooper & Joyce sp. nov.

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Type: Australia, Queensland. Cook District: Steve Irwin Wildlife Reserve, 4 June 2022, W. Cooper 2854 & T. Hawkes (holo: CNS 152656 [2 sheets CNS + spirit], iso: 6 sheets to BRI, CANB, K, L, MO, M).

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Figure 2. Aglaia fellii showing tessellated flaky bark. (Cooper 2854 & Hawkes, CNS). Photo W. Cooper.

Figure 3. Aglaia fellii showing A. a typical solitary-flowered inflorescence (Cooper 2853 & Hawkes, CNS). B. a 4-flowered inflorescence with petals aging from green to brown (Cooper 2853 & Hawkes, CNS). C. immature fruit. (Cooper 2854 & Hawkes, CNS). Photos T. Hawkes.

Figure 4. Aglaia fellii Type specimen (W.Cooper 2854 & Hawkes CNS).

Diagnosis. Similar to Aglaia cooperae Pannell but differs in the trifoliolate leaves (v. 5–7 leaflets); leaflets obovate (v. elliptical); leaflets chartaceous (v. coriaceous); inflorescence to 7 mm long (v. 25–30 mm long); flower diameter c. 2 mm (v. 2.5–3 mm); petals glabrous (v. densely clothed in scales); staminal tube glabrous (v. clothed in scales); fruit obovoid and c. 15 mm long (v. subglobose and 17–25 mm long).

Small tree to c. 7 m high, trunk diameter at breast height to 30 cm; bark grey, tessellated, flaky; branches glabrous; twigs densely tuberculate; newer twigs, petioles, petiolules, peduncles, pedicels, leaflets, bracts, sepals and fruit clothed in rusty peltate scales with fimbriate margins. Leaves compound, alternate; petiole 5–10 mm long; leaflets 3; lateral petiolules 1.5–3 mm long, pulvinus at base; terminal petiolules 2–3 mm long with a pulvinus at base; petiolules and pulvinulus grooved adaxially; lamina discolorous, obovate, 20–55 mm long, 10–17 mm wide, chartaceous; base decurrent; apex bluntly acute or obtuse; margin entire; abaxially and adaxially clothed in scales which are denser along primary vein, dehisced scales leave a pitted surface; venation brochidodromous; primary veins raised on both sides; secondary veins 8–12 pairs, slightly raised on both surfaces; tertiary venation reticulate. Inflorescence axillary or ramiflorous, mostly an erect solitary flower or occasionally a 3- or 4-flowered raceme to 7 mm long; peduncle c. 2.5 mm long; bracts solitary at base or up to 4 set partway along pedicels, c. 0.5 mm long and wide, triangular, base truncate, apex acute; pedicels 1.25–4 mm long. Flower fragrance not detected, diameter c. 2 mm; calyx cupular with 5 sepals, lobes broadly ovate, c. 1 mm long; petals 3 (rarely 4), c. 2 mm long and 1.5 mm wide, hooded at apex, concave, glabrous, green to brown with cream margins; staminal tube globose, c. 1.5 mm long, aperture diameter c. 0.25 mm; anthers oblate, inserted at apex, c. 0.1 mm long and 0.5 mm wide; ovary obovoid, c. 1.25–2 mm high and 0.6 mm wide, glabrous, stigma 5-lobed, apex often 3-cornered; ovules 2 or 3. Fruiting peduncle c. 2.5 mm long; pedicel c. 2.5 mm long; bracts persistent at pedicel base; sepals persistent at apex and densely scaly. Fruit a 2- or 3-locular drupe, obovoid, c. 15 mm long, 13–13.5 mm wide, densely clothed in small, rusty peltate scales with fimbriate margins; 5-lobed stigma c. 1.2 mm long and persistent at apex; seeds 2 or 3, c. 10 mm long and 7 mm wide, testa brown; aril not seen.

Other specimens examined. Moaning Scrub, Steve Irwin Wildlife Reserve, Nov 2020, Cooper 2716, Fell, Hawkes, Jensen & Venables (CNS); Moaning Scrub, Steve Irwin Wildlife Reserve, June 2021, Cooper 2764, Fell & Jensen (CNS); Moaning Scrub, Steve Irwin Wildlife Reserve, June 2022, Cooper 2853 & Hawkes (CNS); Near gravel pit, Bramwell, June 2021, Cooper 2768, Fell & Jensen (CNS); Near gravel pit, Bramwell, Nov 2021, Cooper 2817, Addicott & Zich (CNS); Steve Irwin Wildlife Reserve, July 2018, Fell DGF IRRS284, Cook, Cook & Davidson (BRI).

Figure 2. Aglaia fellii showing tessellated flaky bark. (Cooper 2854 & Hawkes, CNS). Photo W. Cooper.

Figure 4. Aglaia fellii Type specimen (W.Cooper 2854 & Hawkes CNS).

Phenology. Both flowers and fruits have been recorded in June.

Distribution & habitat. Aglaia fellii is endemic to rainforest patches on Steve Irwin Wildlife Reserve and Bramwell Station on Cape York Peninsula, north Queensland, where it is currently known to occur at three sites at altitudes between 80–110 m. These forests are broadly consistent with Qld Regional Ecosystem 3.5.4 - Semi-deciduous notophyll vine forest on northern plateaus on red earth soils on remnant lateritic surfaces (Queensland Herbarium 2021).

Aglaia fellii is an understorey tree that occurs beneath a closed canopy typically dominated by Stenocarpus verticis Foreman, Welchiodendron longivalve (F.Muell.) Peter G.Wilson & J.T.Waterh and Dinosperma erythrococcum (F.Muell.)T.G.Hartley. Other co-occurring species include Acacia fleckeri Pedley, Acacia polystachya A.Cunn. ex Benth., Aglaia elaeagnoidea (A.Juss.) Benth., Aidia racemosa (Cav.) Tirveng., Ailanthus tripyhsa (Dennst.) Alston, Arytera bifoliolata S.T.Reynolds, Brachychiton velutinosus Kosterm., Canarium australianum F.Muell., Celtis philippensis Blanco, Celtis timorensis Span., Cordia dichotoma G.Forst., Denhamia peninsularis J.J.Halford & Jessup, Dimorphocalyx australiensis C.T.White, Drypetes deplanchei (Brongn. & Gris) Merr., Falcataria toona (F.M.Bailey) Gill.K.Br., D.J.Murphy & Ladiges, Garuga floribunda Decne., Gossia floribunda (A.J.Scott) N.Snow & Guymer, Gyrocarpus americanus Jacq., Margaritaria dubium-traceyi Airy Shaw & B.Hyland, Medicosma riparia (Proven) T.G.Hartley, Meiogyne cylindriocarpa (Burck) Heusden, Miliusa traceyi Jessup, Mimusops elengi L., Rhodamnia australis A.J.Scott and Sersalisia sericea (Aiton) R.Br.

Aglaia fellii is only known from within three well separated patches of rainforest on residual lateritic (or bauxitic) low plateaus and rises with well-drained red earth soils. Similar patches are scattered between the Wenlock and Jackson rivers with another concentration between the Wenlock and Mission rivers (Stanton and Fell 2005) where the species may also occur.

Conservation status. Aglaia fellii is known from three small stands of 10–30 individuals each. Two of these stands are conserved in the private Steve Irwin Wildlife Reserve. The greatest threat to the rainforest habitat of Aglaia fellii is the impact of fire. One population occurs close to the southern margin of a rainforest patch where past fire incursion is evident. Tropical cyclones cause catastrophic damage and accumulation of debris that increases the flammability of rainforests; the increased likelihood of such extreme stochastic weather events with climate change means that A. fellii populations are particularly sensitive to these sorts of events in the future.

Based on known locations, the extent of occurrence of A. fellii is estimated to be 78 km^2 and area of occupancy is 12 km^2 (calculated with GeoCat; Bachman et al. 2011). As such, Aglaia fellii is eligible for nomination as Endangered [EN B1ab(i, ii, iii, iv)+B2ab(i, ii, iii, iv)] according to Queensland’s nomination procedure based on the IUCN Red List Categories and Criteria (IUCN 2012).

Etymology. The specific epithet honours David G. Fell (1962–), a botanist who has made outstanding contributions to knowledge of the flora of Cape York Peninsula, and who made the first collection of this taxon and recognised its novelty.

Notes. In many Aglaia species, male and female flowers cannot be easily distinguished morphologically (Pannell 1992:32). Floral segments of A. fellii seen by the first author, whether they be vestigial or functional (ovaries, stigmas, anthers and ovules) all appear similar and therefore the sexuality of A. fellii cannot be ascertained at present. All fruit observed have been solitary.

Aglaia fellii is most similar to A. cooperae Pannell and A. monticola W.E.Cooper & P.I.Forst., but is distinguished from both by its trifoliolate leaves and usually solitary flowers (or much-reduced inflorescences). Flowers of A. fellii and A. cooperae usually have three petals (rarely four) unlike other species in section Aglaia which always have five or six. These two species occur in disjunct areas on Cape York Peninsula and both are only known from small populations.