14.07 ×PUCCIPHIPPSIA Tzvelev
Stephen J. Darbyshire

Plants perennial; cespitose. Culms to 23 cm. Sheaths closed for 1/3–2/3 their length, glabrous; auricles absent; ligules membranous; blades flat or folded, glabrous. Inflorescences compact panicles. Spikelets laterally compressed, with (1)2–3(4) florets; rachillas prolonged beyond the base of the distal floret; disarticulation above the glumes. Glumes usually 2, occasionally 1, unequal, membranous, hyaline, acute to obtuse; lemmas unawned; paleas 2-veined, veins spiculose; anthers indehiscent. Caryopses absent.

×Pucciphippsia consists of hybrids between Puccinellia and Phippsia. Two different hybrids are known. Only one, ×Pucciphippsia vacillans, grows in the Flora region. Pucciphippsia czukczorum Tzvelev is currently known only from the Chukotsk Peninsula in northeastern Russia, although its parents, Puccinellia wrightii and Phippsia algida, have both been found in Alaska on the Seward Peninsula, and in Greenland on the Hayes Peninsula and in the Ammassalik region. Both hybrids are completely sterile, as is indicated by their indehiscent anthers and lack of caryopses. They differ from Puccinellia in having small, compact panicles, and from Phippsia in usually having more than one floret per spikelet.

SELECTED REFERENCE Hedberg, O. 1962. The genesis of Puccinellia vacillans. Bot. Tidsskr. 58:157–167.

1. ×Pucciphippsia vacillans (Th. Fr.) Tzvelev

Culms 7–15(23) cm, erect, glabrous. Sheaths closed for 1/3–2/3 their length; ligules 0.5–2.7 mm, apices entire, truncate, rounded or acuminate; blades 1.5–6(8) cm long, 1.5–3 mm wide. Panicles 1.5–4.5 cm long, 1–2 cm wide; branches smooth; primary branches 1.3–14 mm, erect to ascending. Spikelets 2–3.5 mm, pedicellate; rachillas glabrous or pubescent, internodes 0.2–2.2 mm, prolonged beyond the uppermost floret. Glumes glabrous; lower glumes 0.4–0.8 mm, (0)1-veined, occasionally absent; upper glumes 0.5–1.4 mm, 1–3-veined, obtuse; lemmas 1.8–2.6 mm, (1)3-veined, pilose basally, particularly on the veins, apices entire or erose, truncate to acute; paleas 1.5–2.5 mm; anthers 1–3, 0.5–1 mm. 2n = 21.

×Pucciphippsia vacillans is a sterile hybrid between Puccinellia vahliana and Phippsia algida. It grows in damp, open habitats such as wet meadows, wet tundra, pond margins, and imperfectly drained areas in silt, till, and moss. It is currently known in North America from Axel Hedberg, Bathurst, Cornwallis, Ellesmere, Devon, and Baffin islands in arctic Nunavut, and from Midgaardsormen, Greenland. Outside North America, it is found on Svalbard and Novaya Zemlya islands, where both parents are also present.