Puccinellia maritima: A New Host for the Smut Fungus Ustilago striiformis

Abstract

The isolated island of North Rona, 70o km north-west of Cape Wrath, in the Outer Hebrides, has not been extensively studied from a botanical point of view. The common salt-marsh grass, Puccinellia maritima (Huds.), Parl. is known to grow there, in fair abundance, and recently a collection bearing smut-infected leaves has been received at Kew. The habit of the smut causing raised, longitudinal streaks, at first covered by the epidermis, but later splitting open to expose the dark-brown, powdery spore-mass appeared very reminiscent of the stripe-smut of grasses, Ustilago striiformis (Westend.) Niessl., and the presence of sub-globose, yellow-brown, warted spores I I-14 ptm diameter confirmed this diagnosis. Puccinellia maritima has not previously been recorded as a host for this species, even though the grass is generally distributed and often common around the shores of the British Isles, western coasts of Europe and elsewhere in the northern hemisphere (Clapham, Tutin & Warburg, 1962) and the smut itself is also common and widespread (Ainsworth & Sampson, 1950; Zundel, I953) occurring on a wide range of host grasses. In view of this, the comparatively extreme isolation of the locality makes this new host record all the more interesting. Though originally referred to Poa, Puccinellia maritima has also been referred by some authors to Glyceria, and it is interesting that its leaf smut should prove to be U. striiformis, found also on species of Poa, and not U. longissima (Sow. ex. Schlecht.) Meyen, common on Glyceria maxima (Hartm.) Holmb. and G. fluitans (L.) R. Br., which has much smaller and paler, smoothwalled spores. SCOTLAND. Outer Hebrides, North Rona, on Puccinellia maritima (Huds.) Parl., peaty soil in bird-colony, 30 Jun. 1976, 0. L. Gilbert & P. M. Holligan 8 (K).