Dryopteris dilatata

Broadleaf Dornfarn ( Dryopteris dilatata )

The Broadleaf Dornfarn ( Dryopteris dilatata, Syn: Dryopteris austriaca ) is a common flowering plant in the genus of worm fern ( Dryopteris ).

Description

The overhanging fronds of summer green fern are arranged in rosettes. They reach a length of up to 150 centimeters. The petiole is quite short, it is only half as long as the lamina and densely covered with light brown, dark brown in the middle of the shed. The leaves are pinnate three -to four- fold, from triangular to oval outline (name ) and is tapered. Its upper side is dark green. The square leaflets are cut very finely mucronate at the edge. The sporangia are sitting in two rows on the bottom of the spore-bearing fronds.

The Broadleaf Dornfarn is quite similar to the ordinary Dornfarn, especially when the fronds are young and still without sporangia. The best distinguishing feature of the scales on the petiole; they are the ordinary Dornfarn only light brown and do not have a dark brown midsection.

The Broadleaf Dornfarn has the chromosome number 2n = 164 It is allotetraploid. Two of his genomes derived from the fine Limb Dornfarn ( Dryopteris expansa ), the other two probably by the North American species Dryopteris intermedia.

Occurrence

The Broadleaf Dornfarn comes in damp, shady forests ago on mostly low lime, sandy rocky soils. It has its focus in high montane beech or spruce forests. Its total distribution includes the temperate latitudes of Europe, the mountainous areas of southern Europe, the Caucasus, extending over Siberia to Kamchatka, Sakhalin, North America.