Carex otrubae
Podp. False Fox-sedgeRhizome short; shoots densely tufted. Culms erect, sharply trigonous, smooth below, scabrous above, 30–60(–100) cm long, c. 1.5–2 mm diam. Leaves shorter or longer than culms, to 60 cm long, blade 3.5–4.5 mm diam; sheath white with green veins, leaf sheath front (inner face) not cross-rugulose, the leaf sheath back transversely-septate, becoming brown, soon decaying; ligule tubular, acute, 5–10 mm long. Inflorescence narrow panicle, becoming dense when in fruit, erect, (1.5–)3(–5.5) cm long, c. 1.5 cm diam., compound, spikes numerous; lowest involucral bract shorter than or longer than inflorescence. Spikes sessile, mostly contiguous or lowermost group separated, erect to spreading at maturity; spikes all or most male above and female below, 0.8–1.4 cm long; male glumes 3.5–4 mm, oblanceolate-elliptic, pale orange-brown with green midrib, apex acute; female glumes 4–5 mm long, ovate, pale red or orange-brown with green midrib, apex acuminate-aristate; utricles 4.5–4.7 mm long, 1.5–1.8 mm diam., ovoid, plano-convex, shiny, strongly nerved, often scabrous on shoulders, green, at maturity red-brown, adaxial epidermis smooth or barely minutely elongate-papillate, the epidermal cells elongate; beak 1–1.5 mm long, bifid, not split at back, apex unwinged, margins scabrous; style 2-fid. Nut oblong-obovoid, biconvex, flat, yellow-brown, 2.3–2.6 mm long.
MuF. Africa (Algeria, Morocco, Tunisia), Eurasia. Naturalised in New Zealand. Native to most of Europe. In Australia currently known only from Victoria. First collected in 1995, from the Cohuna region, with several additional collections from Horfield between 2003 and 2004. Currently appears to be confined to irrigated pasture, and paddocks. Jermy et al. (2007) comment that it is a species of heavy soils.
Very close to Carex vulpina (not naturalised in Australia). Carex otrubae and C. vulpina have long been considered difficult to separate due to their morphological similarity, and intraspecific variation in both species. Several morphological characters have been used to distinguish between the two species, but these can be variable. One of the more reliable characters has been the shape of the adaxial epidermal cells of the utricles, but even here there is some overlap between the two species. The adaxial surface of the utricles in the Victorian plants is more or less smooth or barely minutely papillate, and the epidermal cells are elongate. In contrast the utricles in C. vulpina are obviously minutely papillate, with more or less isodiametric cells. Porley (1999) suggested that internal leaf anatomy characters provide an unequivocal way of distinguishing between the two species. However, subsequent studies have shown this to be inconclusive (Smith & Ashton 2006). Smith & Ashton (2006) have suggested that stomatal shape may be of use to differentiate the two species, but more work is required (Jermy et al 2006).
Jermy, A.C.; Simpson, D.A.; Foley, M.J.Y.; Porter, M.S. (2007). Sedges of the British Isles, edn 3. Botanical Society of the British Isles.
Porley, R.D. (1999). Separation of Carex vulpina L. and Carex otrubae Podp. (Cyperaceae) using transverse leaf sections. Watsonia 22: 431–432.
Smith, C.; Ashton, P.A. (2006). Distinction between the sedges Carex vulpina L. and C. otrubae Podp. and the potential for identification of hybrids . Watsonia 26: 15–25.
