Pteridium Pteridium, (L.) Kuhn

1. P. aquilinurn (L.) Kuhn in Decken, Reis. Ost. Afr. Bot. 3 (3): 11 (1879)

( Pteris aquilina L. ).

Leaves 40-400 cm, ovate-triangular, more or less woolly on the lower surface, glabrous or almost so on the upper; margins glabrous; petiole tomentose at base, becoming glabrous above; pinnules shortly acuminate to obtuse, usually almost at right angles to the costa. Indusium cibate. 2/7= 104. Almost throughout Europe; mainly on mountains in the south. All except Is Fa Sb.

A cosmopolitan species with several geographical races, not all of which are well defined. Most European plants are placed by Tryon in var. typicum , but var. latiusculum Underw. , which has the indusium glabrous and the pinnules at an oblique angle to the costa, is widely distributed in N. and C. Europe. P. aquilinurn subsp. brevipes (Tausch.) Wulf , FI. Tour. 1: 20 (1927) is found in the Caucasus and extends to Krym, and has leaves coriaceous and thickly lanate beneath; its relationship to the main European populations needs further investigation.