Plants perennial; rhizomatous. Culms to 38 cm. Sheaths closed for 1/3-3/4 of their length; ligules membranous, acute to truncate, lacerate; blades flat or folded, glabrous. Inflorescences partly open panicles; branches stiff, glabrous, lower branches sometimes reflexed. Spikelets with 2-4 florets, somewhat flattened. Glumes subequal, ovate, membranous, acute; calluses with scant, stiff hairs; lemmas ovate, membranous to subcoriaceous, 1(3)-veined, apices truncate and lacerate-dentate; paleas 2-keeled, glabrous; anthers indehiscent; lodicules 2, membranous. Caryopses apparently absent.

×Arctodupontia is a sterile hybrid between the two monotypic genera Dupontia and Arctophila. It is intermediate between the two parents.

1.   ×Arctodupontia scleroclada (Rupr.) Tzvelev

Culms 13-25(38) cm. Ligules 2-4 mm; blades 2-6 cm long, 1.5-4 mm wide. Panicles 4-7 cm, partly or completely exserted. Spikelets 3.5-7 mm. Glumes 3-6 mm; lower glumes 1-veined; upper glumes 1(3)-veined; lemmas 3-5 mm, paleas about as long as the lemmas; anthers to about 2 mm. 2n = unknown.

×Arctodupontia scleroclada is known from Mansfield Island in northern Hudson Bay and one location in Russia. Plants that are morphologically intermediate between the two parents are not uncommon. The hybrids differ from their parents in being sterile (as indicated by their indehiscent anthers) and in having lemmas with truncate, lacerate to dentate apices, whereas Dupontia has lemmas with acute to acuminate apices with a midvein sometimes excurrent, and Arctophila has lemmas with obtuse, entire apices.