| # Festuca of North America |

S.G. Aiken, M.J. Dallwitz, C.L. McJannet, and L.L. Consaul

### Lolium perenne L.

PERENNIAL RYE GRASS, ENGLISH RYE GRASS.

Sp. Pl.: 83. 1753.

Habit. Plants yellowish green, (30–)40–70(–90) cm high, densely tufted, tiller bases stiffly erect or not stiffly erect, bases purplish, horizontal rooting stems absent. Vegetative shoots arising outside, or breaking through the base of existing sheaths.

Vegetative morphology. Sheaths glabrous, not conspicuous at the base of the plant, remaining entire, not conspicuously splitting between the veins, open more than half their length. Collars glabrous. Auricles present, claw-like (often tapering to a narrow point). Auricular cilia absent. Ligules 1–2 mm long, without cilia. Leaf blades (5–)15–25 cm long, more or less lax. Adaxial blade surfaces glabrous or with trichomes, abaxial blade surfaces glabrous. Leaf blades flat (or loosely rolled), 2–4 mm wide. Veins 10–20. Adaxial to abaxial sclerenchyma strands absent. Abaxial sclerenchyma poorly developed, in broad bands or continuous. Ribs relatively well defined. Uppermost culm leaf sheaths not inflated. Flag leaf blades 4–8 cm long. Culm nodes never exposed or becoming exposed, 1 or 2 (when visible).

Floral morphology. Inflorescence spicate, (8–)10–20(–25) cm long. Rachis internodes cuneate in cross section. Spikelets alternating on opposite sides of the rachis. Spikelet edges fitting into the rachis. Spikelets (5–)7–15(–20) mm long, 3–5 mm wide. Proliferating spikelets absent. Florets 5–11. First glumes absent (present only in the uppermost spikelet of an inflorescence). Glumes glabrous, margins not ciliate. First glume 5–10 mm long (if present), veins 2–3. Second glume as long as the first lemma, or almost as long (often longer), (4–)6–10(–12) mm long (nearly as long as the spikelet), veins 2–3. Rachilla internodes 0.5–0.8 mm long, glabrous, or nearly so. Lemma callus not elongated. Lemma (4–)5–7 mm long, with 5 distinct veins in dorsal view (2–4 veins less prominent), glabrous; apex entire or apically cleft. Lemma awn 0–0.2 mm long. Lemma and palea becoming indurate. Palea 5–7(–10) mm long, glabrous between the keels (scabrous on veins). Lodicules without marginal teeth, glabrous, 0.4–0.7 mm long. Anthers 2.9–3.4 mm long. Ovary apex glabrous. Caryopsis 3–4 mm long.

Cytology. 2n = 14, or 42.

Habitat and distribution. Introduced; naturalized, cultivated crop.

Classification. Lolium L.

Notes. Data entered for classification studies.

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations with detailed captions, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa. See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Aiken, S.G., Dallwitz, M.J., McJannet, C.L. and Consaul, L.L. 1996 onwards. Festuca of North America: descriptions, illustrations, identification, and information retrieval. Version: 14th February 2019. delta-intkey.com’. Aiken, Dallwitz, McJannet, and Consaul (1997) should also be cited (see References).

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