Dwarf St. Johnswort - Hypericum mutilum
A pretty annual plant, up to a metre and a half tall, but generally much shorter, with stem first bent like a knee at the base and then erect, with many branches on the upper half.
Like nearly all the species belonging to this genus, the leaves are opposite, undivided, lanceolate and partly embrace the stem. However they lack the characteristic dark glands frequently found on other St. Johnsworts (Hypericum).
At the end of summer the stem and the leaves, previously a typical opaque green, turn a reddish colour and the plant is more easy to recognise than the others.
The small yellow flowers, carried in a corymb (an inflorescence where the individual flowers have stalks of different length but all end at the same height) open from June-July until September.
As its common Italian name (Iperico americano - American St. Johnswort) implies the plant is of north American origin and occurs in Italy as an occasional only in the province of Turin and a few wetlands of Lombardy and northern Tuscany.
Recently, a fascinating hypothesis had been proposed that Hypericum mutilum is autochthonous and distributed over both continents.
If this were proved true, the occurrence of the species at Lake Sibolla and the surrounding wetlands of Cerbaie and Bientina (at Tanali) would take on a greater importance, since in spite of its decline over the last twenty years, considerable populations can still be found.
