Wang, Xin , Stevenson, Dennis , Li, Nan .
Doubt on the foliar nature of Cycad megasporophylls.
"Alles ist Blatt" is a widely-adopted concept since Goethe and remains an influential idea in botany until today. It appears logical that many female parts of gymnosperms are called megasporophylls, although most of them demonstrate little resemblance to a foliar configuration. Their lack of resemblance to foliar parts casts doubt on the long-assumed foliar nature of megasporophylls. Among all gymnosperms, cycads megasporophylls demonstrate by far the greatest overall resemblance to foliar organs. Therefore, any doubt of the foliar nature of cycad megasporophylls is hinged with the valid existence of megasporophylls of seed plants as a whole. Our observation on the megasporophylls of the Cycadales indicates that their megasporophylls can be better interpreted as a metamorphosed shoot or branch rather than a leaf as proposed by Meeuse (1963). This interpretation will make all ovule-bearing parts of seed plants (including Cycadales, Ginkgoales, Coniferales, Gnetales, and Angiosperms) metamorphosed branches and sheds new light on the systematics of seed plants.
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Link to a monography on early angiosperms
1 - Nanjing Institute Of Geology And Palaeontology, 39 Beijing Dong Road, Nanjing, N/A, 210008, China
2 - THE NY BOTANICAL GARDEN, 2900 SOUTHERN BLVD, BRONX, NY, 10458-5126, USA, 718/817-8632
3 - The Fairy Lake Botanical Garden, Shenzhen, Guangdong, 518004, China
seed plant phylogeny.
Presentation Type: Oral Paper:Papers for Sections
Location: Union A/Hyatt
Date: Tuesday, July 10th, 2012
Time: 3:00 PM