Ecology And Growth Habit Of Laveineopteris: A Gymnosperm from the Late Carboniferous Tropical Rain Forests

Cyclopterid leaves were borne on the same Late Carboniferous medullosalean plants that bore the pinnate fronds currently known as Laveineopteris. They were morphologically and anatomically different from the pinnate foliage, and presumably were also physiologically different. The cyclopterids are here interpreted as having been shade leaves and the pinnate foliage sun leaves. The juvenile Laveineopteris plant probably consisted of a monopole sapling bearing only cyclopterid leaves, which optimized growth in canopy shade conditions. On reaching the canopy level, the plant produced a crown of pinnate sun leaves. Cyclopterids were also borne epiphyllously in the proximal parts of the pinnate fronds; this may have represented a transitional light–level between canopy and subcanopy conditions. Thus, in this reconstruction, the cyclopterid leaves were complementary to the pinnate foliage of the adult Laveineopteris plant, and played a key role in its growth habit and ecology.