Saturday, November 20, 2021

[Botany • 2021] Ficus desertorum (Moraceae) • A New Species of Rock Fig for Central Australia

Ficus desertorum B.C.Wilde & R.L.Barrett,

in Wilde & Barrett, 2021.
Photos: A–D by B.C. Wilde; E, F by R.L. Barrett.

A new species of lithophytic fig, Ficus desertorum B.C.Wilde & R.L.Barrett, endemic to arid Central Australia, is described and illustrated. It is distinguished from other species in Ficus section Malvanthera Corner by having stiff lanceolate, dark green, discolorous leaves; many parallel, often obscure lateral veins; petioles that are continuous with the midrib; with minute, usually white hairs and non- or slightly sunken intercostal regions on the lower surface. Previously included under broad concepts of either Ficus platypoda (Miq.) Miq. or Ficus brachypoda (Miq.) Miq., this species has a scattered distribution throughout Central Australia on rocky outcrops, jump-ups (mesas) and around waterholes. This culturally significant plant, colloquially referred to as the desert fig, grows on elevated landscapes in central Australia, including Uluru (Ayers Rock), Kata Tjuta (The Olgas) and Karlu Karlu (Devils Marbles), three of Central Australia’s best-known natural landmarks. Evidence is provided to show these plants are geographically and morphologically distinct from Ficus brachypoda, justifying the recognition of F. desertorum as a new species. Taxonomic issues with F. brachypoda and F. atricha D.J.Dixon are also discussed. Lectotypes are selected for Urostigma platypodum forma glabrior Miq. and Ficus platypoda var. minor Benth.

Keywords: Central Australia; rock figs; Ficus; systematics; taxonomy; ethnobotany

Ficus desertorum B.C.Wilde & R.L.Barrett. 
A: fruiting branch. B: detail of leaf venation, abaxial surface. C: detail of stem and petiole. D: leaf, abaxial surface. E: leaf base and petiole detail. F: mature fruit lateral view. G: longitudinal section of fruit. H: habit and habitat.
Vouchers: A from G. Chippendale s.n. (NSW 927786); B, C, E-G from cultivated material; D from G. Chippendale s.n. (NSW 452252). 
Scale bar: A = 30 mm, b = 10 mm, c, e, f = 15 mm, d = 20 mm, g = 5 mm, h = no scale.
 Illustration by Lesley Elkan.

Ficus desertorum B.C.Wilde & R.L.Barrett.
A: habit on Uluru, NT. This individual has a decumbent habit and flows down the face of Uluru. B, C: foliage and young figs showing typical upright branches and leaves, Karlu Karlu, NT. D: variation in leaf shape. This individual is growing in sand, Simpsons Gap, NT. E: Fruiting branchlet on cultivated plant. F: Figs, petioles and apical bracts on cultivated plant.
Photos: A–D by B.C. Wilde; E, F by R.L. Barrett.

Ficus desertorum B.C.Wilde & R.L.Barrett, sp. nov. 

Type: Uluru (Ayers Rock-Mt Olga) National Park: Uluru (Ayers Rock), Mutitjulu (Maggie Springs) walk, on the ring road, 1.7 km NE of Ranger Station, 19 May 1988, M. Lazarides & J. Palmer 252 (holo: CANB 385988; iso: DNA D0046821).

Diagnostic characters. Distinguished from other Australian species in Ficus section Malvanthera by having stiff lanceolate, dark green, discolorous leaves; many parallel, often obscure lateral veins; petioles that are continuous with the midrib (not constricted); leaves with minute, white or rusty hairs and not or slightly sunken intercostal regions on the lower surface (the aeroles appearing very slightly raised). The leaves of this species separate it from most other native Australian figs, with petioles 9–34 mm long, 1.2–2.7 mm wide, and the lamina lanceolate (occasionally broadly lanceolate or elliptic), (40–)46–120 mm long, (15–)19–44 mm wide, a distinctive length/ width ratio (Fig. 5). Some populations of F. brachypoda s. lat. from the Pilbara region of Western Australia do have a similar leaf shape, but all specimens assigned to F. brachypoda s. lat. differ in the strongly sunken, finely reticulate intercostal regions (or intercostal veins appearing raised) on the lower surface.

Etymology. The epithet refers to the unusual habitat of this species (for Ficus) in the arid centre of Australia, dominated by desert environments

Indigenous names. tywerrk (Alyawarr; Anmatyerr); tjurrka (Arrente); utyeerk, utyeerke (Eastern Arrente); tywerrke (Western Arrente); ili, witjirrki, yili (Pintupi); ili (Pitjantjatjara / Yankunytjatjara); wÿirrki (Warlpiri). The figs as a food are known as mai pulka (Yankunytjatjara). (See Kemp 1891; Cleland and Johnston 1933, 1937, 1939; Johnstone and Cleland 1943; Meggitt 1957; Cleland and Tindale 1959; Maconochie 1970; Hale 1975; Hansen and Hansen 1977; O’Connell et al. 1983; Latz 1995; Everard et al. 2002.) 

Common names. Desert fig (preferred); Wild fig; Rock fig; Native fig.

Distribution. Most common in the greater MacDonnell Ranges of the Northern Territory, from the Devils Marbles, south to the Everard Ranges in South Australia and west to the Rawlinson and Walter James Ranges in Western Australia (Fig. 2A, within dashed ellipse).

Conservation status. The species is widespread and present in a number of national parks and other conservation reserves, but it is usually only found as small populations, so threats such as fire may have localised impacts. 

Brendan C. Wilde and Russell L. Barrett. 2021. Hiding in Plain Sight, Ficus desertorum (Moraceae), A New Species of Rock Fig for Central Australia. Telopea: Journal of Plant Systematics. 24; 283–301. DOI: 10.7751/telopea14668