About Lotus berthelotii Masf.
Lotus berthelotii is an evergreen prostrate shrub or subshrub. It reaches 20 cm (7.9 in) in height and has a creeping or trailing growth habit. Its leaves are split into 3 to 5 slender leaflets; each leaflet measures 1 to 2 cm long and 1 mm wide, and is densely covered with fine silvery hairs. The species produces orange-red to red flowers, which grow on short stalks, are shaped like upward-facing beaks, and are slender overall, measuring 2 to 4 cm long and 5 to 8 mm broad.
The flowers of Lotus berthelotii and some other Canary Island species appear adapted for bird pollination. It was once thought that the original pollinators of these plants (and other genera including Isoplexis and Canarina) were sunbirds that had gone extinct on the Canary Islands, which explained why these plants are rare and classified as endangered, a view supported by early 1954 and 1984 research by Vogel and colleagues. More recent work has shown that these plants are adequately pollinated by non-specialist flower-visiting birds, particularly the Canary Islands chiffchaff Phylloscopus canariensis. The plants even have specific adaptations to infrequent pollination by these birds, such as longer flower lifespans. However, a cultivated population studied by Ollerton et al. (2008) produced no fruit even though the plants received large amounts of pollen on their stigmas. This lack of fruit may be because the studied population was a single self-incompatible clonal genotype. It is unknown whether this is true of all cultivated L. berthelotii plants, but this could have important implications for the species' conservation if it is extinct in the wild.
Lotus berthelotii is grown as an ornamental plant, valued for its needle-like silvery foliage and red flowers. It is used in traditional gardens, in container pots, and in drought-tolerant water-conserving gardens. It has received the Royal Horticultural Society's Award of Garden Merit. A golden orange-flowered cultivar is also grown. This species cannot tolerate freezing temperatures, so it requires winter protection under glass in cold temperate climates. It needs a sheltered location in full sun.
