A smut fungus of Gagea spp. (G. lutea and G. bohemica in GB&I), visible as lesions/pustules on leaves and stems, up to 10 mm in length, that later split to release a dark black-brown powdery mass of spores.
Sori 1-5(-10) mm long, dark blackish-olive-brown ellipsoidal or fusiform pustules on leaves of Gagea lutea in GB&I, initially covered by the epidermis, but then rupturing longitudinally to expose a blackish brown, powdery spore mass. Spores variable in shape and size; subglobose, ovoid, irregular, subpolyhedral or elongate; sometimes with an acute tip or short pedicel; 10.5-19(-24) µm x 9.5-15 µm, yellowish to reddish brown; wall 0.5-1.5 µm thick, apparently one-layered, nearly to finely smooth, moderately densely punctate-verruculose, but dots not affecting the spore profile. Sterile cells few, solitary or in groups of 2-4, subglobose, ellipsoidal, slightly irregular, rarely elongated, collapsed in old specimens, 11-20 µm long, usually of the same colour as the spores; wall 1.5-3(-4) µm thick, one-layered, smooth (but rough under high magnification SEM). Infection systemic, appearing on the same host plant year after year.
Description based on Vánky (2013). For external images see the Bioimages website.
Not formally assessed. Classed as Vulnerable / D2 in GB&I in the provisional Red Data List of Threatened British Fungi (Evans et al., 2006).
The rust Uromyces gageae produces scattered sori on leaves of Gagea lutea, which are roundish to elliptical, 1-3 mm long, covered by a lead-coloured epidermis that splits longitudinally to expose teliospores 26-40 x 18-28 µm. U. gageae is also of conservation interest, and has been preliminarily classed as Vulnerable / D2 (Evans et al., 2006). A similar further species of rust, Uromyces acutatus, has been reported once from Gagea lutea in GB&NI, although more typically found on G. arvensis and Allium sphaerocephalon.
When not in flower, leaves of Gagea lutea could be mistaken for those of Hyacinthoides non-scripta (English bluebell), which is associated with a number of rusts, especially Uromyces muscari. However, sori of that species are considerably smaller than those of Vankya ornithogali, appearing as ovoid- to diamond-shaped clusters of minute pustules.
In GB&I in association with living leaves of Gagea lutea and G. bohemica, and possibly other members of Gagea if present. Originally described from numerous members of Gagea but only two specimens of V. ornithogali have been DNA-barcoded at present, and so could potentially represent a cryptic species complex. Does not occur on Ornithogalum, despite previous records: these are almost certainly either misidentifications of smut or host, or referring to host species later transferred to Gagea (Vánky, 2009).
Scattered throughout England and Wales, mostly encountered in eastern and northern England. Currently reported from VC23 Oxfordshire, VC43 Radnorshire, VC63 SW Yorkshire, VC64 MW Yorkshire and VC66 Durham.
Most likely to be associated with long-established, large host populations, since teliospores overwinter in the soil. Gagea lutea prefers moist, calcareous, shady habitats, e.g. woods, hedgerows, limestone pavements, pastures, riverbanks and stream banks. Mainly lowland.