Causonis maritima (Jackes) Jackes, Telopea

Trias-Blasi, Anna, Dee, R., Jimbo, Tiberius, Jackes, Betsy & Parmar, Gaurav, 2022, Taxonomic revision of Causonis (Vitaceae) in New Guinea, Edinburgh Journal of Botany 79 (1895), pp. 1-10 : 6-8

2. Causonis maritima (Jackes) Jackes, Telopea 23: 70 (2020).

Cayratia maritima Jackes, Austrobaileya 2(4): 366 (1987). – Type: Australia, Queensland, Cook, Lakefield National Park, 9.3 km north of Ranger’s Cottage , 15.116°S, 144.316°E,

26 vi 1982, Jackes, B. R. s.n. (holotype BRI [barcode AQ0441384 ]; isotypes A [barcode 00051579], CANB [barcodes CANB 375543.1 , CANB 375543.3 , CANB 375544.2 , CANB 375544.4 ], DNA [barcode DNA D0056167], K! [barcode K000072595 ], L! [barcodes L. 0763085, L. 0763086], MEL [barcode MEL 1582485 A], NSW [barcode NSW 830674 , NSW 171693 ]) .

Herbaceous climber. Stem angular, 2–4 mm in diameter, very branched, usually glabrous with simple hairs at nodes when young; tendril 3-furcate (occasionally 2-furcate), slender, wiry, leaf-opposed, cylindrical, with a non-coiling section followed by coiling section,

1.5–14 cm long, glabrous, lacking adhesive discs at the tips. Leaves compound, 3-foliolate, alternate; petiole 1–8 cm long, hairy as on stem, central petiolule 0.5–2.5 cm long, lateral petiolules 1–8 mm long, hooked hairs sometimes present; central leaflet blade ovate to rhomboid, 1–10 × 1–7 cm, base cuneate to rounded; lateral leaflet blade 2–8 × 2–6 cm, base oblique; margin dentate to crenulose, apex acute; adaxial surface almost glabrous at maturity except for the presence of uniseriate 3- to 14-celled hooked hairs on the midrib, abaxial side usually glabrous, occasionally with hooked hairs at the junction of the petiole and the lamina; veins inconspicuous. Inflorescence a ramified, axillary, mostly dividing dichotomously, corymbose, compound dichasium, 2–12 cm long; peduncle 1.5–16 cm

long, hairy as on leaf to glabrous, pedicels 1–3 mm long, papillose. Buds ovoid, 1.25–2 × 1–2 mm. Calyx cupuliform, entire, margin sinuate, 0.5–0.75 × 1.5–2 mm, papillose. Corolla petals 4, ovate, 1.25–2.25 × 1–2 mm, apex cucullate, papillose. Stamens 4; filaments flattened, broadening at the base, 0.5–1 mm long; anthers orbicular, medifixed, 0.4–0.75 mm long. Ovary adnate to the disc; disc with 4 lobes, glabrous. Style conical, slender, 0.5–1 mm long; stigma inconspicuous. Fruit a berry, subglobose, 0.5–1.25 mm in diameter, glabrous, smooth, base attenuate. Seeds 2–4, triangular-obovoid, 5–7 × 4–7 mm, ventral infolds side conspicuous with 2 keels to cup-shaped cavities, dorsal side convex with a linear chalazal knot, endosperm nearly T-shaped in cross-section. See Figure 2A, F–H .

Distribution. Australia, Brunei, China, India, Indonesia (Borneo, New Guinea, Sulawesi), Malaysia, Moluccas Islands, Papua New Guinea, Singapore, Solomon Islands and Vietnam.

Distribution in New Guinea. Indonesia (Irian Jaya) and Papua New Guinea (Autonomous Region of Boubainville, Milne Bay) (see Figure 1 ).

Habitat and ecology. Coastal, alluvial or sandy soil, swamps, forest edge, regrowth; near sea level to 3500 m.

Phenology. Flowering and fruiting throughout the year.

Proposed IUCN conservation category. Causonis maritima is distributed from India and China to North Australia with no apparent threats, and therefore it can be treated as Least Concern (LC). In New Guinea, although we only have four collections, the EOO is calculated to be 676,693 km 2, and therefore it is also considered to be Least Concern (LC).

Additional specimens examined. INDONESIA. Irian Jaya: Snow Mountains [Maoke Mountains]: Bernhard Camp Idenburg River [Taritatu river], 3°40′S, 140°15′E, iv 1939, Brass 13947 ( K [ K000871696 ], L [ L.2329267]). NW New Guinea, Pionier bivouac, vi 1926, Docters van Leeuwen 9362 ( BO [2 duplicates], K [ K000871697 ]) .

PAPUA NEW GUINEA. Autonomous Region of Bougainville province: SW of Toiumonapu Plantation, 6°10′S, 155°20′E, 2 vii 1963, van Royen NGF16418 ( BO, K [ K000871707 ], L [ L.2329188]). Milne Bay province: Subdist Alotau, Haumo River, 3 miles out of Alotau on road to Gurney 2 miles east of Rabe village , 10°20′S, 150°25′E, 21 iii 1976, Larivita LAE70553 ( K [ K000871688 ; sheet 2]) .

Figures

Figure 1. Map showing the distribution of Causonis australasica, C. maritima and C. trifolia in New Guinea.

Figure 2. Distinctive characters in New Guinea Causonis. A and B, Tendrils: A, Causonis maritima; B, C. trifolia (adapted from Jackes, 1987). C–H, Seeds: C–E, Causonis trifolia (C, cross-section; D, ventral view; E, dorsal view); F–H, Causonis maritima (F, cross-section; G, ventral view; H, dorsal view). Drawn by A. Trias-Blasi.