Lotus
Sponsor
Kindly sponsored by a member of the International Dendrology Society.
Credits
Julian Sutton (2023)
Recommended citation
Sutton, J. (2023), 'Lotus' from the website Trees and Shrubs Online (treesandshrubsonline.
Family
- Fabaceae
Very roughly 125 species of herbaceous perennials, annuals and (rarely) shrubs, native to Europe, Africa, Asia and Australia. Leaves pinnate or palmate, usually sessile, with (3–)5(–9) more or less sessile leaflets, the lower 2 often stipule-like; true stipules absent, or reduced to small dark glands. Inflorescence an axillary, stalked, 1– to many-flowered umbel; peduncle with a bract usually represented by a conspicuous leaf with 1–3(–5) leaflets; bracts beneath individual flowers usually highly reduced or absent. Calyx bell- or trumpet-shaped; 5 teeth sometimes connate into 2 lips. Corolla with 5 lobes (banner, 2 wings, 2 forming the more or less beaked keel). 9 stamens united by their filaments to form a tube, the 10th free. Fruit a linear to ovoid many-seeded legume, almost always longitudinally dehiscent. (Wei, Kramina & Sokoloff 2010; Cullen et al. 2011).
We include Lotus on the fringes of our project since this essentially herbaceous genus includes a few subshrubs which have often been placed in Dorycnium. These produce annual herbaceous stems from a slowly lengthening woody framework. They originate in the Mediterranean Basin, and suit sunny, well-drained positions in milder parts of our area. Like most other peas they have nitrogen-fixing root nodules and are well suited to nutrient-poor soils.
The sub-shrubby species of interest here were included within Linnaeus’s (1753) concept of Lotus, but through the 20th century they were usually segregated into Dorycnium, with an effectively capitate inflorescence and short, thick fruits, following a revision by Rikli (1902). The morphological grounds for this were sometimes questioned, and as molecular studies became available it was clear that Dorycnium nested within Lotus (Kramina et al. 2016 and references therein), although relationships within Lotus are still far from clear.
We discuss the well known, often silvery-leaved L. hirsutus, and the rarely grown L. dorycnium which sits at the heart of a complex of poorly understood forms. Among other Lotus species, L. berthelotii Masf. is an orange-red flowered prostrate subshrub from Tenerife; it is too tender to be grown outside in our area year-round so is not included here, but is often used in summer bedding and hanging baskets. The familiar European L. corniculatus L. is an entirely herbaceous perennial; listed surprisingly often by British nurseries, it perhaps looks its best in flower-rich lawns on poor, light soils.
