Luzula wahlenbergii, commonly known as Wahlenberg's woodrush, Piper's wood rush^[2] or Reindeer Wood-rush,^[3] is a perennial species of plant in the genus Luzula of the Juncaceae (rush) family.^[1]

Luzula wahlenbergii is in the Diprophyllatae section of the genus Luzula of the Juncaceae (rush) family.^[4] L. wahlenbergii was first formally described by the Austro-Russian botanist Franz Josef Ruprecht in 1845.^[1]

With regards to the etymology of the binomial: the generic name Luzula could come from the Italian lucciola ("to shine, sparkle") or the Latin luzulae or luxulae, from lux ("light"), inspired by the way the plant's hairs sparkle when wet with dew.^[5] Another etymology sometimes given is that it does derive from lucciola but that this meant a midsummerfield, or from the Latin luculus, meaning a small place; the same source also states that this name was applied by Luigi Anguillara (an Italian botanist) in 1561.^[6] The second part of the binomial, wahlenbergii is in tribute to the Sweedish botanist Göran Wahlenberg, who studied the flora of the northenmost areas of Sweeden.^[3]

Luzula wahlenbergii is a perennial and herbaceous plant around 15–35cm high in a loosely caespitose fashion.^[1] The stem has 1–2 cauline leaves which are flat, as well basal leaves which are 5–10 cm × 3–5 mm in size; the upper leaves of L. wahlenbergii are smaller, sized at 3–5 cm × 2–4 mm.^[1] The leaf margins of L. wahlenbergii are papillose-serrulate with an acutely-shaped leaf tip.^[1]

The inflorescence of Luzula wahlenbergii is lax, and could be described as a 'nodding panicle', having 10-30 flowers which are 4 cm in length and 3 cm in width - these flowers are pedunculated and borne singly in 2–3 clusters.^[1] The bracteoles of L. wahlenbergii are fimbriate-ciliate near their apex and up to 2.0 mm long, whilst the lower bract is 4−10 mm long.^[1] L. wahlenbergii has equal tepals which are 2.0–2.8 mm long, entire, brown and acuminate, along with six stamens and anthers which are 0.4–0.6 mm long.^[1] L. wahlenbergii has a style and stigma 0.5 mm long and c.1 mm long respectively, the plant also has equaling filaments.^[1]

The seed capsule of Luzula wahlenbergii is ellipsoidal, subacuminate with exceeding tepals; the seed capsule is 2.0–2.4 × 1.1–1.5 mm in size and segments are brown in colour.^[1] The dark, castaneous brown seeds of L. wahlenbergii are 1.2–1.4 × c. 0.7 mm in size, narrowly ellipsoidal, lack an appendage and have a base which is fibrilate.^[1]

Luzula wahlenbergii has a relatively wide distribution, growing across Arctic Eurasia, far-east Russia (including Transbaikal), Alaska, Greenland, Canada and the mountains of Scandanavia. ^[1]

Luzula wahlenbergii is an arctic-alpine plant,^[1] and grows in mainly moist habitats. These include but are not limited to:wet grasslands, mossy tundra,^[1] the shores of lakes, alluvial rivers or gneissic seashore and alpine creeks.^[7]