The taxonomy of Lotus corniculatus L. sensu lato

Roberts, Ian Murray (1984) The taxonomy of Lotus corniculatus L. sensu lato. MSc(R) thesis, University of Glasgow.

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Abstract

Plant material corresponding.to L. corniculatus s.1. was collected from a number of sites in the British Isles, continental Europe, North America and New Zealand, and grown in experimental plots. Various morphological features were examined and the plants identified as L. corniculatus s.s., L. uliginosus and L. tenuis according to published descriptions. Two forms of L. corniculatus were recognised; those with all stems decumbent and those with any or all stems ascending or erect. The range of variability in the characters most frequently used for identification was determined. The standard deviation of these characters for each population was compared. A number of characters: hairiness, shape and length of calyx teeth, stem length, leaflet shape, and leaflet epidermal cells showed a wide range of variation and considerable overlap between species. However, the characters of appearance of calyx teeth in bud, presence of rhizomes, seed length and number of flowers per inflorescence showed some discontinuity, proving of most value for discriminating between species. Other characters: hollowness of stems, prominence of leaf veins and leaflet length: breadth ratio were found to be indicative of species but were not consistently reliable. Transplantation of plants from various wild habitats into more or less uniform conditions showed that under cultivation significant changes take place in leaflet length and leaflet length: breadth ratio. Morphological differences between the two forms of L. corniculatus were often found to be greater than between the erect form of L. corniculatus and L. uliginosus. In some cases difficulty was experienced in distinguishing these two species in the field. Chromosome counts confirmed the number of chromosomes in L. corniculatus as 24 and in L. tenuis and L. uliginosus as 12. It is proposed that sufficient distinction exists between the two forms of L. corniculatus in Britain to warrant their having sub-species status. It is suggested that appropriate nomenclature for the erect form is sub-species vulgaris Koch and the decumbent form sub-species arvensis Pers., following work by MacDonald (1946). The descriptions are as follows: L. corniculatus L. ssp vulgaris Koch Plants varying in form from haying some, but not all, stems decumbent to ascending or erect. Stems (2) 25-50 (60) cm, usually solid at base but frequently becoming hollow. Internodes long 15-38cm. Peduncles (2) 3-10 (13) cm. Leaves glabrous or hairy, ovate or obovate aften mucronate, 8-21mm long, usually more than twice as long as wide, veins usually absent or scarcely apparent. Inflorescence 3-8 flowered. Calyx teeth erect in bud. Underground stems absent. (2n = 24). L. corniculatus L. ssp arvensis Pers. Plants with all stems decumbent, low and spreading. Stems (5) 10- 25 (35) cm, usually sol id. Internodes short 5-13cm. Peduncles erect (1) 2-7 (9) cm. Leaves globous or hairy, ovate or obovate (3) 5-12 (15) mm long, usually less than half as long as wide, veins usually absent. Inflorescence 1-6 flowered. Calyx teeth erect in bud. Root stock short and thick, often woody with underground stems. (2n=24). Existing cultivars have been identified as the erect form of L. corniculatus. They show much morphological similarity with no ability to propagate themselves by rhizomatous growth. A range of unexploited sources of genetic material exists which could be used for the establishment of a breeding programme to improve the agronomic potential of indigenous L. corniculatus.

Item Type: Thesis (MSc(R))
Qualification Level: Masters
Additional Information: Adviser: Gareth Williams
Keywords: Botany
Date of Award: 1984
Depositing User: Enlighten Team
Unique ID: glathesis:1984-71620
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 10 May 2019 14:04
Last Modified: 10 May 2019 14:04
URI: http://theses.gla.ac.uk/id/eprint/71620

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