Asplenium Trichomanes - Subspecies

Subspecies

Asplenium trichomanes has diploid, tetraploid and hexaploid cytotypes, which it has been argued should be recognised as distinct species. A triploid cytotype (a sterile hybrid between the diploid and tetraploid cytotype) is also known. Within these cytotypes several subspecies are recognised, including

• Asplenium trichomanes subsp. trichomanes prefers acidic rocks such as sandstone, basalt and granite. In Europe and North America it is most often found in mountainous areas and is commonest in the north. It is a delicate plant with a slender stipe and rachis and relatively few pinnae. Diploid.
• Asplenium trichomanes subsp. quadrivalens prefers calcareous rocks such as limestone and dolerite and often grows on the mortar in walls. It is commoner than A. t. subsp. trichomanes in much of Europe but is less widespread in North America, although it is present in southern North America where ssp. trichomanes is absent. Compared to the nominate subspecies it is stouter and has more pinnae which are more square in shape and have less of a stalk. The fronds tend to grow close to the rock while those of A. t. subsp. trichomanes tend to arch away. Tetraploid.
• Asplenium trichomanes subsp. pachyrachis (syn. Asplenium csikii) is mainly found on limestone rocks and walls. It is small and delicate, grows close to the rock and has a rigid, fragile stipe and rachis. Tetraploid.
• Asplenium trichomanes subsp. coriaceifolium (syn. Asplenium azomanes): Majorca, Spain, Morocco. Tetraploid.
• Asplenium trichomanes subsp. hastatum. Tetraploid.
• Asplenium trichomanes subsp. inexpectans. Diploid.
• Asplenium trichomanes subsp. maderense. Madeira, Azores. Hexaploid. Hexaploids also occur in Australia and New Zealand.
• Asplenium trichomanes nothosubsp. staufferi. Tetraploid (pachyrachis × quadrivalens).
• Asplenium trichomanes nothosubsp. barraraense. Tetraploid (coraceifolium × quadrivalens).
• Asplenium trichomanes nothosubsp. lovisianum. Tetraploid (hastatum × quadrivalens).
• Asplenium trichomanes nothosubsp. moravicum. Tetraploid (hastatum × pachyrachis).
• Asplenium trichomanes nothosubsp. melzeranum. Triploid (hastatum × inexpectans).
• Asplenium trichomanes nothosubsp. melzeri. Triploid (quadrivalens × inexpectans).
• Asplenium trichomanes nothosubsp. tadei-reichsteinii. Triploid (pachyrachis × inexpectans).
• Asplenium trichomanes nothosubsp. lusaticum. Triploid (trichomanes × quadrivalens).
• Asplenium trichomanes nothosubsp. malacitense. Triploid (coraceifolium × inexpectans).