gallers on Glyceria

1a On above-ground parts => 2

1b Root hairs variously swollen, usually bottle- or club-shaped; each containing a rotund, hollow, multipartite spore ball. G. fluitans: Sorosphaerula radicalis

2a On culms and leaves => 3

2b Whitish, at surface yellowish or brownish patches, which envelope a large area of the upper part of stem, of which further development is stunted. Node of stem rarely swollen, encircled by fungus stroma, yellowish when mature; several nodes may be affected; flowering stunted; stroma contains narrow asci and filamentous spores. G. striata, Glyceria sp.: Epichloë glyceriae

2c On inflorescences or flowers. Spikelets elongated; flowers ± greened, bleached if strongly infected. G. fluitans: Aceria tenuis

3a Malformations caused by fungi => 4

3b Leaf blade rolled, irregularly curved and twisted; caused by a dull green to reddish, 2 mm long aphid. G. declinata, fluitans, maxima, notata, striata: Sipha glyceriae

3c Yellow-red midge larvae living under leaf sheaths. G. maxima: Octodiplosis glyceriae

4a Fungus, usually completely pervading many shoots, sporulates mainly all around the internodes of the at least initially excessively elongated, non-flowering shoots. G. fluitans: Tranzscheliella hypodytes

4b The infestation usually affects all shoots of infected plant, in which sterile culms often grow initially rigidly erect and bear stunted, pale-green leaves. The smut sori extend over the complete length of the leaf blades in several parallel stripes. G. arundinacea, declinata, fluitans, lithuanica, maxima, nemoralis, notate: Ustilago filiformis

4c Long conspicuous stripes on chlorotic leaf tissue caused by rust fungus. Glyceria spp.: Puccinia striiformis

= In similar sori on G. fluitans, notata: Ustilago davisii, differing from U. longissima by its larger spores (8–14 x 6–12 μm)

= Another smut fungus, sporadically occurring on Glyceria, distinguished by its spores clustered in balls, belongs to the Urocystis agropyri species complex