Taxonomy

  • Ferns with large rhizomes covered in fleshy stipules
  • Thick petioles bear large, bipinnate blades that are articulated by swollen bases
  • Leaves are usually 5-6m long and 3m wide
  • The pinnules are elliptic, with free venation and small dentation at the apex
Morphology
  • Giant ferns to 7m tall
  • Rhizomes massive, globose, erect, radially arranged, to 150cm tall and to 100cm wide
  • Stipules 10cm wide when dry (to about 20 cm when fresh), densely long-scaly above, triangular-keeled, the edges irregularly erose
  • Leaves bipinnate, up to 5-7m long, petiole up to 2m long, up to 6 cm wide, the swollen base to 15cm wide, without nodes
  • Blades up to 4m long and up to 3m wide, deltoid-elliptic, bright green above, slightly glaucous or lighter green below, with up to 25 (sub-)alternating pinna pairs
  • Pinnae with up to 50 pairs of (sub)alternating pinnules, the pinnules occasionally forked or with a minute basal lobe (up to 1cm long)
  • Largest lateral pinnules linear to ovate-lanceolate, 7-13 times longer than wide, 9-17 x 0.9-1.8cm, 13-15 x 3-3.8cm in young plants, widest below or at the middle, apices acute to acuminate, bases obtuse-truncate (or cordate), margins entire with a serrulate apex
  • Terminal pinnae linear to ovate-lanceolate, similar to the lateral, 8-13(-16) x 0.9-2(-4)cm, widest below the middle, margins serrulate at apex
  • Veins variable, some simple, usually paired at base or forked occasionally twice forked, 8-16 veins per cm
  • Sori in two-rowed clumps of 9-14, and these placed on the veins in a submarginal row; juveniles forming the first pair of pinnae when plant is 4cm tall, bipinnate leaves appear when the plants are larger than 40cm, only adult plants (> 3m long) make fertile leaves
Diagnostic description

Angiopteris is a complex genus and the differences between the species with giant rhizomes and bipinnate leaves are poorly understood, because herbarium material is always fragmentary.

It is of intermediate size. A. lygodiifolia is much smaller (leaves to 3m) and A. teijsmanniana is much larger (leaves to 9m). A. fokiensis has warty petioles, and A. angustifolia has a different shape of the stipules.

Evolution

Angiopteris is sister to Marattia s.s, which forms a clade sister to Christensenia. These are sister to a clade uniting Eupodium and Ptisana.

Within Angiopteris, A. evecta is not well-resolved in the latest phylogenies, but the A. evecta complex is sister to the subgenus Archangiopteris.

Lookalikes

Of the bipinnate Angiopteris species, this species resembles:

  • A. angustifolia
  • A. lygodiifolia
  • A. fokiensis
  • A. madagascariensis
  • A. chauliodonta
  • A. teijsmanniana