Dichapetalum cremeum W.E.Cooper, sp. nov.

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Type: Australia: Queensland. Cook District: Portland Roads Road, 14 April 2022, W.Cooper 2849 & J.Pritchard (holo: CNS 154152 [2 sheets + spirit]), iso: 7 sheets to be distributed to BRI, CANB, DNA, L, LAE, MO, S).

Dichapetalum sp. 1 (Claudie River; B.Hyland 7006); Briggs & Leigh (1996)

Dichapetalum sp. Claudie River (B.Hyland 7006); Thomas & McDonald (1989)

[Dichapetalum timoriense auct. non (DC.) Boerl.: Hyland et al. (1994: 303); Jessup in Henderson (2002); Cooper & Cooper (2004), pro parte (as to Qld. occurrence); Zich et al. (2020), pro parte (as to Qld. occurrence)]

Illustrations: (all as D. timoriense) Cooper & Cooper (2004:150); Zich et al. (2020)

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Figure 4. Dichapetalum cremeum: A. Leaf adaxial surface showing petiole taper extending along primary vein (Cooper 2880, Jensen & Zich [CNS]); B. Leaf abaxial surface showing petiole taper extending along primary vein (Cooper 2883, Jensen & Zich [CNS]); C. Hermaphrodite flowers (Sankowsky 2719 & Sankowsky [BRI]); D. Fruit and seeds (Cooper & Jensen 53 [CNS]). Photos: A & B. R. Jensen; C. G. Sankowsky; D. Artwork W.T. Cooper.

Monoecious shrubby scrambler becoming a vine to canopy; stem diameter to c. 57 mm; bark with vertical shallow fissures, lenticellate, rusty-brown on younger stems becoming grey on older stems; some branches back-arching; indumentum appressed or erect, cream-coloured; stipules thread-like, c. 3.5 mm long, sericeous; petioles sub-peltate, 4–10 mm long not including taper; taper along abaxial midrib extending for 2.5–8 mm, long-acuminate at junction with primary vein, usually visible on adaxial and abaxial surfaces of fresh and dried specimens, thinly sericeous, dark brown. Leaves obovate, elliptical or oblong, 70–150 mm long and 25–68 mm wide, coriaceous; adaxial surface with appressed hairs becoming glabrous; abaxial surface with appressed hairs along primary and secondary veins, persisting on primary vein; glands on abaxial surface scattered with a few sometimes near base, glands on adaxial surface absent or 1–7 near base with up to 4 scattered elsewhere on blade, discolorous; base mostly asymmetrical, subcordate or narrowly rounded, rarely cuneate; apex acute, short-acuminate often with an apiculum or rarely narrowly rounded, entire; venation brochidodromous throughout or camptodromous proximally and brochidodromous distally; primary vein flush adaxially and raised abaxially, each with a tuft of hairs at apex on younger growth; secondary veins 6–7 pairs, raised on both sides, angle to primary vein 40–50º; tertiary venation reticulate, densely pitted within each reticulation on abaxial surface. Hermaphrodite inflorescence axillary (often in pairs), up to 30-flowered dichotomously branched panicle or cyme to 21 mm long; peduncle 3–13 mm long, tomentose; bracts at rachis base and mostly at junctions along rachis ovate, c. 0.35 mm long, tomentose; pedicels articulate, 1.5–2.5 mm long, sericeous. Flowers fragrant or fragrance not detected, diameter c. 2.75 mm and c. 2 mm long; calyx hemispherical at base; sepals ovate, 1.5– 2 mm long, abaxially tomentose, adaxially thinly tomentose, yellowish-green; petals broadly elliptical, deeply cucullate, 1.5–2 mm long, glabrous, white, apex emarginate to 0.2 mm; stamens 5, 1.5–2 mm long, filaments strap-shaped, glabrous, anthers introrse; staminodes flat, rhomboid, apex obovate or acute often with 2 uneven acute apices, 0.5–1 mm long, tomentose; ovary ovoid, c. 0.5 x 0.5 mm, densely tomentose; style c. 0.5 mm long, glabrous; stigma 2-lobed, diameter c. 0.25 mm. Fruit peduncle 6–7 mm long; pedicel 2–4.5 mm long; drupe usually 3-lobed and 3-sutured, indehiscent, oblate, diameter 22–45 mm, 15–30 mm long, papillate, clothed in minute erect velvety hairs not visible to naked eye, cream-coloured or yellow, mesocarp 5–8 mm thick; seeds usually 3, wedge-shaped, c. 15 mm long, sculptured, brown. Figs. 1 & 4

Specimens examined: Australia. Queensland. Cook District: Porn. [Portion] 195, Parish of Clerk, Hyland 12907 (CNS); Near airstrip, Rocky River, Silver Plains, Aug 1997, Cooper & Jensen 53 (CNS); Island Scrub 1, Iron Range Research Station, April 2017, Fell IRRS147 (CNS); Gordon Creek, June 2003, Hyland 14853 (CNS); Claudie River, Oct 2022, Cooper 2883, Jensen & Zich (CNS); Claudie River, Nov 1977, Hyland 9539 (CNS); Claudie River, Oct 1980, Hyland 21090V (CNS); Claudie River, Oct 1974, Hyland 7815(CNS); Claudie River, Oct 1980, Hyland 21095V (CNS); Claudie River, April 1992, Fell DF2505 (BRI); 8 km NW of Lockhart River, Oct 1995, Stanton JPS63 (BRI); Gordon Creek, Sept 2015, Cooper 2298 (CNS); Portland Roads Road, April 2022, Cooper 2849 & Pritchard (CNS); Garraway Creek rockpiles, April 1988, Forster PIF 4244 & Liddle (BRI); Nelson Creek mouth to Pascoe River, Iron Range National Park, Oct 2022, Cooper 2891, Jensen & Zich (CNS); Hann Creek, July 2002, Cooper & Cooper 1771 (CNS); Ex-Bamaga, cultivated at Tolga, June 2006, Sankowsky 2719 (BRI, CNS); Mt Cornwallis, Dauan Island, Torres Strait, Feb 1989, Gray 5023 (CNS).

Papua New Guinea. Central District: Rubulogo Creek c. 18 miles N of Port Moresby, April 1967, Pullen 6629 (L); Nunumai, c. 12 km N of Amazon Bay, June 1969, Pullen 7577 (L). Madang District: Nov 1969, Vandenberg & Katik NGF 42367 (L). Morobe District: Burep River NE of Lae, Hartley 10177 (L); Aluki Village, Sep 1982, Katik LAE 74969 & Galore(NSW);

Indonesia. Aru Archipelago: Pulau Baum, April 1993, Nooteboom 5685 (L); Aru Islands, April 1993, Balgooy & Mamesah 6425 (L).

Diagnostic features. Dichapetalum cremeum is similar to D. timoriense but differs from the latter species by the indumentum cream-coloured (v. white); stipules c. 3.5 mm long (v. 4–6 mm long); petiole taper 2.5–8 mm long (v. 1.8–2.5 mm long); leaf base usually asymmetrical, narrowly rounded and rarely cuneate (v. usually symmetrical, cuneate or slightly rounded); inflorescence to 18 mm long (v. to 35 mm long); bracts ovate and c. 0.35 mm long (v. linear, 2–3.5 mm long); flower diameter c. 2.75 and length c. 2 mm (v. diameter c. 5 mm and 2.5–4 mm long); sepals ovate and 1.5–2 mm long (v. elliptical and c. 2.5 mm long); petals incised to c. 0.2 mm (v. incised to c. 0.6 mm); staminodes flat, rhomboid, apex obovate or acute often with 2 uneven acute apices, 0.5–1 mm long (v. spathulate or strap-shaped, apex 2-lobed, lobes rounded or mostly acute; fruit pedicel 2–4.5 mm long (v. 0.5–2 mm long); mature fruit broadly oblate, 3-sutured, yellow, papillate and with sparse minute indumentum only visible with a lens (v. globular, ovoid, pear-shaped or cordate, 4-sutured, densely rusty-hairy, hairs visible to naked eye, yellowish-green).

Phenology. Flowers have been recorded in February, April and June; fruit has been recorded in September and October.

Distribution & habitat. Dichapetalum cremeum occurs in evergreen and semi-deciduous notophyll and mesophyll vine forest on Cape York Peninsula north from the Cedar Bay area near Cooktown to Dauan Island in the Torres Strait, at altitudes below 80 m. It also occurs in Papua New Guinea and the Aru Islands of Indonesia. In Australia it co-occurs with: Aglaia argentea Blume, Aleurites moluccanus (L.) Willd., Alstonia scholaris (L.) R.Br., Alstonia spectabilis R.Br., Argyrodendron polyandrum L.S.Sm., Atalaya australiana Leenh., Blepharocarya involucrigera F.Muell., Brachychiton velutinosus Kosterm., Canarium australianum F.Muell., Celtis philippensis Blanco var. philippensis, Cordia dichotoma G.Forst., Diospyros fasciculosa (F.Muell.) F.Muell., Drypetes deplanchei (Brongn. & Gris) Merr., Lagerstroemia archeriana F.M.Bailey subsp. archeriana, Miliusa traceyi Jessup, Mimusops elengi L., Semecarpus australiensis Engl., Sloanea langii F.Muell, Strychnos psilosperma F.Muell., Tetrameles nudiflora R.Br. and Vitex helogiton K.Schum.

Conservation status. Based on known localities, the Extent of Occurrence (EOO) of Dichapetalum cremeum is estimated to be 53,000 km|^2^| and Area of Occupancy (AOO) is 60 km|^2^| (calculated with GeoCat; Bachman et al. 2011). The species is represented in conservation reserves and there are no immediate threats evident. As such, D. cremeum would be categorised as being of Least Concern.

Etymology. The epithet cremeum is from the Latin cremeus (cream-coloured), in reference to the cream colour of the ripe fruit.

Notes. At Kutini-Payamu (Iron Range) National Park, vines shorter than 3m with copious quantities of female flowers did not set fruit. Fertilisation may only occur when the vine has reached the subcanopy.

Some specimens of D. cremeum from New Guinea and South East Asia have been determined as D. timoriense. Further studies might prove that D. cremeum occurs beyond the area listed above.

Sterile specimens of D. cremeum are indistinguishable from sterile D. schlechteri Krause, however the former differs by sepals adaxially thinly tomentose (v. glabrous); petals broadly ovate (v. spathulate); petal apices emarginate to 0.2 mm (v. divided to centre of petal); stamens same length as petals (v. stamens much longer); ovary ovoid and 0.5 x 0.5 (v. globose, diameter 1.2 mm); stigma 2-lobed (v. 3-lobed).