Austronea Mart.

Martínez-Azorín, Mario, Crespo, Manuel B., Alonso-Vargas, María Ángeles, Dold, Anthony P., Pinter, Michael & Wetschnig, Wolfgang, 2018, Austronea (Asparagaceae, Scilloideae), a new genus from southern Africa, including the description of seven new species, Phytotaxa 365 (2), pp. 101-129 : 105-107

Austronea Mart. -Azorín, M.B.Crespo, M.Pinter & Wetschnig gen. nov.

Genus notabilis ad Fusifilum similis, sed singulari characterum combinatione ab eo et ceteris generibus Urgineoideae diversus et facile distinguendus, nempe foliis generaliter coriaceis, incrassatis vel incrassato-coriaceis; inflorescentia saepissime subcorymbosa vel capitata, juniore plerumque nutante; perigoniis in alabastro rubescentibus vel viridi-lutescentibus, tepalis saepissime a basi bene cupulato-connatis lobis patentibus (rarissime lobis usque ad basem liberis); filamentis staminibus linearibus vel lanceolatis (nec manifeste fusiformibus), levibus vel raro inferne papillatis; ovario viridi vel luteo-aurantiaco, haud albido; seminibus plerumque trigonis, subpyramidalibus plicatis et in angulis anguste alatis (nec sublenticulari-ellipticis, complanatis et in agulis late alatis).

Type:— Austronea marginata (Thunb.) Mart. -Azorín, M. B.Crespo, M.Pinter & Wetschnig

Bulbous geophyte. Bulb hypogeal, usually with compact scales but rarely loose, outer scales brownish and membranous. Roots thickened and branched. Leaves 1 to several per bulb, usually dark green, commonly leathery, terete or flat, rarely plicate, linear to ovate or rounded, usually smooth, glabrous to hairy or hispid. Inflorescence a capitate or subcorymbose raceme with long flower pedicels born on an elongated peduncle, rarely short racemose with short pedicels and peduncle, commonly the apex of the peduncle and the inflorescence nodding at early stages of development, but soon erect at anthesis. Pedicels of buds very short forming a dense apical raceme, distinctly elongating at anthesis to form a capitate or subcorymbose inflorescence, rarely also very short in flower. Bracts lanceolate, acute, the lowermost with a spur from a slight curve outgrowth abaxially to a long, wide spur with obtuse and lobate apex; bracteoles absent. Flowers pentacyclic, trimerous, stellate, erect-patent, diurnal, usually opening in the afternoon and withering in the evening. Flower buds usually reddish or brownish-green. Tepals 6, biseriate, usually connate at the base to form a cup and patent free portion of tepals, rarely almost free from the base and spreading; adaxial side of tepals reddish, brownish, greenish or yellowish, rarely almost white; abaxial side of tepals with a distinct reddish, brownish, or greenish darker central band. Stamens 6, erect or spreading, not connivent to the style; filaments filiform to flattened, usually connate to the perigone and arising at the end of the perigone tube, but sometimes almost free when tepals are not distinctly connate, straight or rarely sigmoid, smooth or rarely papillate below; anthers ovate to oblong, dehiscing by longitudinal slits along their whole length; pollen yellow. Ovary ovoid to oblong or subglobose, trigonous, brown, red or green, sometimes with white maculae, differentiated from the style. Style white, narrow, erect, exerted, straight or slightly curved. Stigma small, papillose and indistinctly trigonous. Capsule ovoid-globose, triloculate, loculicide, valves splitting to the base, with the withered perigone segments circumscissile below and forming an apical cap. Seeds up to 30 per capsule, black, shining, commonly trigonous in outline, tetrahedrally folded and narrowly winged along the angles, with subovoid embryo ending into a long filamentous hilum, testa loose and easily detachable from the endosperm, with colliculate testa cell walls.

Etymology:— Austronea (Austro- = south;- nea = referring to the genus Urginea ). This name refers to part of the species traditionally named Urginea or more recently Drimia sensu lato in southern Africa, that represent a genus endemic to Southern Hemisphere. Urginea s.str., based on the first typification by Adamson (1942) (see Speta 1998b), is endemic to western Mediterranean Basin and includes only Urginea fugax Steinheil (1834: 328) and U. ollivieri Maire (1938: 453) , as confirmed in our phylogenetic analyses.

Main diagnostic characters and taxonomic relationships:—Species of Austronea are easily distinguishable by a syndrome of morphological characters that allow clear recognition such as the usually leathery and thickened leaves; the subcorymbose or congested raceme commonly nodding at early developing stages, the reddish to green-yellowish tepals (see flower buds), which are usually connate at the base to form a distinct cup and patent free lobes, the filaments linear to lanceolate (not distinctly fusiform), smooth or rarely papillate below, the ovary green to yellow-orange, and the seeds commonly trigonous in outline, tetrahedrally folded and narrowly winged along the angles. As commented above, flower and inflorescence general morphology approach Austronea to Fusifilum , a fact supported by our phylogenetic analyses in which both genera form strongly supported sister clades, but both differing in clear morphological characters. Apparently, flower morphology in Austronea is unspecialized, differing from that in Litanthus Harvey (1844: 314) , Thuranthos Wright (1916: 233) , Rhadamanthus Salisbury (1866: 37) , and Rhodocodon Baker (1880: 280) , supporting their generic identity within Urgineoideae in the last century. However, species of Austronea were already recognized as a distinct group within Drimia sensu lato by Manning & Goldblatt (2003, 2007), to include the species related to Drimia marginata . The basic trimerous flower pattern in Hyacinthaceae is constant, as in most petaloid monocot families, and variation mainly regards degree of connation of tepals, adnation and/or connation of stamens and morphology of the gynoecium, which were the main basis for generic circumscriptions in the past. However, based on previous phylogenetic studies, it is evident that the latter flower characters, such as degree of connation of tepals and adnation of filaments, appeared several times in the evolution as convergent events related to independent and usually distant clades or genera ( Martínez-Azorín et al. 2011). Furthermore, within clades or genera, these convergence events also occurred, rendering some of these single characters as not sufficient for generic circumscription. For instance, some genera in Ornithogaloideae , such as Nicipe Rafinesque (1837: 54) , show flowers with free or rarely connate tepals ( Martínez-Azorín et al. 2011). Degree of connation of tepals has also been used in the past to segregate genera in Urgineoideae . Among the genera with distinctly connate tepals, Drimia , Litanthus , Rhadamanthopsis ( Obermeyer 1980: 137) Speta (1998b: 74) , Rhadamanthus , Rhodocodon , or Urgineopsis Compton (1930: 107) are easily recognized. However, many other species described as Urginea or Drimia sensu lato from southern Africa show unspecialized flowers in which tepals vary from free to shortly connate ( Adamson 1942, Baker 1897, Hilliard & Burtt 1982, Huber 1969, Jessop 1977, Stedje 1987), and this was the basis for rejection of some genera in the subfamily, such as for instance Urgineopsis , which show shortly connate tepals ( Manning et al. 2004). This is also the case in Austronea , in which tepals are usually connate for ca. 1–1.5 mm to form a distinct cup but sometimes are almost free, and therefore, this character alone should not be used for generic circumscription. Both quantitative and qualitative characters of flower morphology must be combined with those of fruits and seeds and also vegetative, as it occurs in other plant families, and then solid groups of taxa can be accepted at genus rank, as shown by Martínez-Azorín et al. (2011). This syndrome of morphological characters allows confident identification of Austronea species and also a multigeneric treatment in Urgineoideae (M. Martínez-Azorín and collaborators, in preparation), being similar to that widely accepted in Hyacinthoideae , where Manning et al. (2004) accept 11 genera only for southern African taxa, plus several more in the Northern Hemisphere.

Ecology:—Species of Austronea are usually found on patches of open vegetation, in sandy or loamy soil, on flats or rocky ground on mountain slopes.

Distribution:—Western and southern regions of southern Africa, spanning southern Namibia and western and southern South Africa, reaching deeply inland of the southern African subcontinent.

Karyology:—Apparently not studied yet (cf. Goldblatt et al. 2012).

Number of species:—In the present revision, 18 species are accepted in Austronea . All are difficult to find in the field because of their cryptic appearance. Leaves are usually small and appressed to the ground and might also be wellcamouflaged. Moreover, they present delicate inflorescences with usually small flowers and their leaves are usually dry at flowering time. This fact, in combination with the poor conservation of flower structures in herbarium vouchers, confound the taxonomy of the group and explains why several species of this genus have remained unnoticed until now. Our field work in South Africa and Namibia, combined with the cultivation of numerous Austronea samples in the glasshouse in the last decade, also attest the existence of further undescribed species, still poorly known, that holds promise of further increase of the number of species in this genus.

Further observations:— Idothea Kunth (1843: 341) is the only described genus which includes a species of Austronea in its original concept. Ten species were included in the former fitting in general terms the characters of Drimia s.str., including Drimia media Jacquin (1795: 15) , D. purpurascens Jacquin (1812: 48) , D. ciliaris Jacquin (1795: 15) , D. villosa Lindley (1830 : pl.1346), D. elata Jacquin (1794: 15) , D. pusilla Jacquin (1794: 15) , and D. humilis Berg. ex Ecklon (1827: 2) . In addition, Kunth (1843) included three more Idothea species, albeit in doubt as suggested by the question mark in their combinations; these include: Anthericum pusillum Jacquin (1795: 18) , A. physodes Jacquin (1795: 18) (both currently placed in Fusifilum ), and Anthericum marginatum Thunberg (1794: 63) . The latter species is here included in Austronea . Idothea has been considered a synonym of Drimia by most recent authors. Stearn (1978) typified Idothea on Idothea elata (Jacquin 1794: 15) Kunth (1843: 343) , and therefore fixed the use of that name, avoiding conflicts with Austronea .