Holcus lanatus L.

Publisher Website
Google Scholar
Abstract
Yorkshire fog (H. lanatus) is distributed throughout the British Isles and is frequent on most soil types. Its distribution in Europe lies almost completely within the area bounded by the January isotherm -2[degree]C (28.4[degree]F), and the July isotherm 26.7[degree]C (80[degree]F). The alti-tudinal range of H. lanatus in the British Isles approximates 2000 ft. (610 m), but is reported to reach 4920 ft. (1500 m) on the Continent of Europe. Plants are perennial and caespitose, but colonization is possible as a result of extension from rooting at the shoot nodes. All parts are softly hairy. The veins of the sheaths and the glumes show varying intensities of purple coloration, but plants devoid of anthocyanin are found. Panicle shoots can grow up to 70 cm in favoured habitats. The spikelet has 2 florets, the lower hermaphrodite but the upper is normally male. The lemma of the latter has a hooked awn which is usually enclosed within the glumes. Anthesis is at its maximum during June/ July, and in good weather occurs twice a day; 6a. m. and 1 p. m. G.M.T. (Aberystwyth). Anthers are exserted from both florets of the spikelet almost simultaneously. The species is wind pollinated, and sets seed freely. Self-compatibility although possible in some plants, is not very successful. The caryopses from cross-pollination may become viable within 9 days of fertilization. Seeds which have become incorporated in the top 7 in. (18 cm) of undisturbed swards retain their vitality even after being buried for many years. Seeds stored in the laboratory showed 5% viability after 12 years. H. lanatus is a diploid, 2n=14, and plants may have up to 2 accessory B-chromosomes, while 2 pairs of chromosomes show secondary constrictions. Natural hybrids with H. mollis have been reported, and artificial hybrids with the different chromosome races of H. mollis have been produced. H. lanatus appears to be im-mune to yellow dwarf virus.

This publication has 0 references indexed in Scilit: