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- Title
<E1>GIgantonoclea</E1>: an enigmatic Permian plant from North China.
- Authors
Zi-Qiang, Wang; Wang Zi-Qiang
- Abstract
<E1>Gigantonoclea</E1>is a distinctive and enigmatic plant from the Permian of North China proper, with an unusual frond architecture and a pollen organ and vascular structure which are unique; it demonstrates a sudden rise and a rapid extinction. This paper reviews previous work on Asian gigantopterids and describes new material from the Upper Permian of Shanxi Province, including a new type of pollen organ (<E1>Jiaochengia lagrelii</E1>) and two new species of frond (<E1>Gigantonoclea crenata</E1><E1>G. pubescens</E1>).<E1>Jiaochengia</E1>shows opposite, dissected and rather modified microsporophylls, laxly aggregating into an independent organ, which is markedly different from '<E1>Gigantotheca</E1>' from Fujian. This presents evidence of heterogeneity among Asian gigantopterids and partly supports a relationship with the Carboniferous Callistophytales.<E1>Jiaochengia</E1>sporangia have what may be the first record of a waxy covering on the outer surface of a fossil plant, which is interpreted to have functioned to repel water, to protect against fungal attack and to scatter light. According to Hickey's rule, the venation of true<E1>Gigantonoclea</E1>fronds consists of three orders of main veins (rachis, midvein and secondary veins) and two orders of anastomosing veins (tertiary veins and veinlets). Certain putative '<E1>Gigantonoclea</E1>' species from South China and some peripheral areas of North China do not have this type of venation and are thus excluded from the genus. Frond dimorphism is common among gigantopterids in both North and South China and can be compared with the amphibious variation from submerged to emergent leaves in extant aquatic plants.<E1>G. pubescens</E1>has a thick, bi-layered adaxial cuticle with an indumentum covering with dense papillae and trichomes bases, and deeply sunken, papillate stomata, suggesting that it favoured more arid conditions. An observed gradient from pubescent to glabrate or even glabrous gigantopterid c...
- Subjects
CHINA; SHANXI Sheng (China); EXTINCT plants; FOLIAR diagnosis; PALEONTOLOGY
- Publication
Palaeontology, 1999, Vol 42, Issue 2, p329
- ISSN
0031-0239
- Publication type
Article
- DOI
10.1111/1475-4983.00076