Polystichum aculeatum
Lobed shield fern
The lobed shield fern ( Polystichum aculeatum, also Glanzschildfarn or Thorny shield fern ) is a fern species that is typical of canyon woods and scree slope forests in Central Europe.
Description
The fronds of the fern are evergreen bipinnate 30 -90cm long, rarely longer. In outline they are lanceolate to linear. Their reason is clearly narrowed. The petiole makes less than one-third of the total length.
The rather crude leaf blade is on the top glossy dark green, occupied on the underside paler and sparsely with small chaff shed. The pinnules (ie the second-order pinna ) sit and are easy sichelig curved forward. Characteristic is the lowest pinnules, which is significantly greater than all others, usually a half to twice as large.
Fronds of young plants are often simply pinnate, making them similar to those of Lance Schildfarns because of the forward bending of the pinnules.
Overall, the fern in the habit, however, is highly variable.
Distribution and habitat requirements
The lobed shield fern is found in the mountains and mountain ranges of Europe and the Caucasus and the northern Indian Himalayas. Finds from China, Japan or North America seem doubtful and most other species have now been assigned.
It is the most common Central European shield fern - type and is absent-minded on humus-rich, rocky and humid mountain and ravine forests, both on lime and lime-free on the ground. In the Alps, he does not rise above the tree line.
Others
The lobed shield fern can form with the lance shield fern Polystichum hybrids x illyricum.