Thesium humifusum is a species of hemiparasitic flowering plant in the family Santalaceae found in western Europe and north-western Africa, known as bastard-toadflax.
Within continental Europe, Thesium humifusum is found throughout France,[1] Spain[2] and Italy.[3] In the Netherlands, it is very rare, being now restricted to a single dune system near Katwijk aan Zee.[4] In Belgium, it can be found in coastal dunes in Flanders, and perhaps one site in Wallonia.[5] It is the only species of Thesium in Great Britain,[6] and is there considered 'scarce'.[7] Thesium humifusum may also occur in parts of North Africa.[8]
Thesium humifusum is a hemiparasitic plant that steals nutrients from hedge bedstraw (Galium album) or lady's bedstraw (Galium verum).[4] Although it can be abundant in appropriate habitats, its low growth habit and inconspicuous flowers mean that it is often overlooked.[7] In Great Britain, it is restricted to downlands over chalk or oolitic limestone in southern England.[9] Elsewhere, it may also grow in sand dune systems.[4]
Thesium humifusum usually grows flat along the ground, only occasionally producing more erect flowering stems. Its leaves are a yellowish green colour and are strap-shaped and up to 25 mm (1 in) long, with a single central vein. The flowers are also yellowish, and only 2–3 mm (0.08–0.1 in) long. They have five tepals, five stamens, and a single ovary with three ovules and one style.[6][4]
Thesium humifusum was first described by Augustin Pyramus de Candolle in the 1815 third edition of his Flore Française.[8] In English, it is known simply as 'bastard-toadflax'.[6]
Thesium humifusum is a species of hemiparasitic flowering plant in the family Santalaceae found in western Europe and north-western Africa, known as bastard-toadflax.
