Gigantopterids †

Ecology & Form

• Possible vine or upright plant

• Grew in wetlands as well as arid conditions

• Known mostly from compression and impression fossils 

• They were among the most striking and important plants of the Cathaysian flora of Sino-Malaya, also called Gigantopteris flora (Wang, 1999)

Stem

• Woody stems with spines

• Wood contains vessel elements similar to gnetophytes and angiosperms

 Aculeovinea yunguiensis †

• • These stems are woody and vessel-less with a sparganum cortex and prickles

  • Stems were probably connected to Gigantopteris guizhouensis leaves

 Vasovinea tianii †

• A permineralized eustelic stem for the Late Permian of China

• Eustelic with 5-9 wedge-shaped mesarch segments, each with wood with vessels

• Prickles, trichomes, and compound hooks are found along stems suggesting a climbing habit

Leaves

• Large bilaterally symmetrical leaves in mature plants (Giganopteris, Gigantopteridium, Cathaysiopteris, Zeilleropteris, Gigantonoclea)

  • Dichotomous venation is known in some; 

  • Reticulate venation found in others with anastomosing higher-order veins 

• Some leaves are compound fronds; mature leaves may have been simple

• Oleanane found in leaves (similar to angiosperms)

• Earliest evidence of foliar nyctinasty has been documented in gigantopterid leaves (Feng et al., 2023)

  • Symmetrical insect damage indicates folding of the leaves, probably during the night

Gigantopteris nicotianaefolia † (type species) 

• Leaves from Permian of South China (Yan, 1983)

• Leaves up to 50 cm long with an entire margin (Glasspoll et al., 2004)

  • Pinnate venation with 4 orders of veins which give rise to "large, polygonal meshes with finer veinlets anastomosing to form meshes and blind endings" (Taylor et al., 2009)

Gigantopteris guizhouensis †

• Permineralized simple leaves from the Late Permian of southeast China (Li & Tian 1990)

• Stomata are paracytic with uniseriate trichomes on the abaxial surface

• Many secretory cavities are within the mesophyll of the leaf

• Prickles are found along the abaxial midrib

Gigantopteridium americana †

• Leaves from Permian of North America (White, 1912)

Gigantopteridium marginervum †

• Leaves from Middle Permian of China (Yao & Liu, 2004)

• Amphistomic leaves (both sides of leaf) with cyclocytic stomata

• Subsidiary cells on abaxial (lower) surface have papillae

• Subsidiary cells on adaxial (upper) surface lack papillae and are heavily cutinized

Cathaysiopteris †

• Leaves from the Permian of Asia

• Forked and pinnately-compound leaves up to 20 cm in length with a sinuous margin and pinnate veins with three orders of venation 

• The tertiary veins are closely-spaced and the meshes are long and narrow (Mamay et al., 1986)

Zeilleropteris †

• Leaves from the Permian of Asia

• Dichotomously-divided leaves over 30 cm in length and up to 27 cm wide with four orders of venations

Gigantonoclea †

• Leaves from Asia and North America, which were possibly lianas (Li et al., 1994) or possibly aquatic, based on frond dimorphism (Wang, 1999)

• Leaves similar to Gigantopteris, but with a toothed margin and veins that are less complex

Delnortea abbottiae †

• Permineralized leaf from Early Permian of North America (Mamay et al., 1988)

• Simple, petiolate leaves mostly (3-5 cm) are oblong-elliptical with an entire to crenulate margin and a clasping base

• Sclerenchyma occurs on the enrolled leaf margin, which may aid in the structure of the leaf

• Venation is pinnate with four orders of veins; veins terminate at the margin