Lolium arundinaceum, commonly known as tall fescue, is a cool-season, perennial C3 grass species native to Europe and introduced to North America and other parts of the world. It naturally occurs in grasslands and coastal marshes. Tall fescue is grown in a range of cultivars, widely used for livestock forage, in lawns and recreational areas as turf, and occasionally for managing soil erosion. Most publications have used the names Festuca arundinacea or, more recently, Schedonorus arundinaceus for this species, but DNA studies appear to have settled a long debate that it should be included within the genus Lolium instead.
Description Tall fescue is a long-lived tuft-forming perennial with erect to spreading hollow flowering stems up to about 165 cm (5 ft 5 in) tall (exceptionally up to 200 cm) which are hairless (glabrous), including the leaf sheaths, but with a short (1.5 mm) ligule and slightly hairy (ciliate) pointed auricles that can wrap slightly around the stem. The leaf blade is flat, up to about 10 mm wide, and also glabrous, but rough on both sides and the margins. The tillers (non-flowering stems) are typically shorter but otherwise similar to the culms. The leaves have prominent veins running parallel the entire length of the blade. Emerging leaves are rolled in the bud (convolute vernation). Note that most grasses are folded not rolled, which make this a key identification feature on tall fescue. Flowering typically occurs from early June until late August, with an erect to slightly nodding open panicle up to about 40 cm (1 ft 4 in) long. The branches are normally in pairs, each of which has 3-18 spikelets, which are 9–15 mm long and comprise 4-8 bisexual florets and two short, unequal glumes. The lower glume has only 1 nerve whereas the upper one has 3. The lemmas typically have a short (3 mm) awn arising just below the tip. Each floret has 3 stamens with anthers about 3–4 mm long. The fruit is a nut or caryopsis with the seed tightly enclosed by the hardened lemma and palea.
Taxonomy Tall fescue was first described (as Festuca arundinacea) by the German naturalist Johann Christian Daniel von Schreber in 1771. Its inclusion within the genus Festuca was due to the similarity of the flowers and inflorescences. However, there has been much debate since 1898 about its relationship to the genus Lolium, largely because of hybridization with Lolium perenne (species in separate genera are far less likely to form hybrids than those within the same genus). Recent DNA studies have shown that it should indeed be considered a ryegrass (Lolium) rather than a fescue (Festuca) because these species are more closely related to each other, despite the fact that ryegrasses have inflorescences of spikes rather than panicles. Its chromosome number is 2n = 42.
Distribution and status
Tall fescue is native to Europe, West Asia and North Africa. It was introduced to North and South America, Australia and Southeast Asia. It is widespread in the United States. Occurs in fields, meadows, waste areas and pastures. The cultivated species has become a common sight in California grasslands and habitats, such as the California coastal prairie plant community, since its introduction this species has been a topic of debate.
Habitat and ecology In its native European environment, tall fescue is found in damp grasslands, river banks, and coastal areas. The British National Vegetation Classification lists it as a minor component in a range of grassland types, but it is particularly characteristic of its own MG12 Festuca arundinacea community, which is a tussocky type of pasture that occurs in brackish grazing marshes around the south and west coasts. This vegetation type is also home to some uncommon plants such as parsley water-dropwort and slender spike-rush. Tall fescue is also found in a number of salt marsh and maritime cliff communities. In New Zealand, where it is introduced, the species is particularly prolific in salt marshes, where it is often dominant. Native to Europe, tall fescue has established itself in introduced regions like North America, where it thrives in habitats such as grasslands, wetlands, riparian corridors, and marshy landscapes. Its Ellenberg values in Britain are L = 8, F = 6, R = 7, N = 6, and S = 1, which show that it favours damp, brightly sunny places with neutral soils and moderate fertility, and that it can occur in slightly brackish situations.
Endophyte association Tall fescue can be found growing in most soils of the southeast including marginal, acidic, and poorly drained soils and in areas of low fertility, and where stresses occur due to drought and overgrazing. These beneficial attributes are now known to be due in part to a symbiotic association with the fungus Epichloë coenophiala,(formerly Neotyphodium coenophialum). This association between tall fescue and the fungal endophyte is a mutualistic symbiotic relationship (both symbionts derive benefits from it). The fungus remains completely intercellular, growing between the cells of the aboveground parts of its grass host. The fungus is asexual, and is transmitted to new generations of tall fescue only through seed, a mode known as vertical transmission. Thus in nature, the fungus does not live outside the plant. Viability of the fungus in seeds is limited; typically, after a year or two of seed storage the fungal endophyte mycelium has died, and seeds germinated will result in plants that are endophyte-free. The tall fescue–endophyte symbiosis confers a competitive advantage to the plant. Endophyte-infected tall fescue compared to endophyte-free tall fescue deters herbivory by insects and mammals, bestows drought resistance, and disease resistance. In return for shelter, seed transmission, and nutrients the endophyte produces secondary metabolites. These metabolites, namely alkaloids, are responsible for increased plant fitness. Alkaloids in endophytic tall fescue include 1-aminopyrrolizidines (lolines), ergot alkaloids (clavines, lysergic acids, and derivative alkaloids), and the pyrrolopyrazine, peramine.
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