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Angiosperms and their gymnosperm sister groups
Angiosperms and their gymnosperm sister groups
Diversity
Diversity
The proposed anthophyte clade includes the glossopterids, pentoxylales, bennettitaleans, gnetophytes, caytoniales, and angiosperms (Doyle & Donoghue, 1987)
This is a debated clade, and molecular studies tend not to support the anthophyte clade hypothesis
Many research articles have rejected the inclusion of gnetophytes in this clade (Goremykin et al., 1996; Chaw et al., 1997; Hansen et al., 1999; Qiu et al., 1999; Samigullin et al., 1999; Chaw et al., 2000; Sanderson et al., 2000; Magallon & Sanderson, 2002; Hajibabaei et al., 2006)
Although some research that includes fossil taxa possibly supports the Gnetales in the Anthophyte clade (Rothwell et al., 2009)
Features
Features
Synapomorphies for the anthophyte clade include:
Scalariform pitting in secondary xylem
Once-pinnate microsporophylls
Single ovule per cupule
Derived non-saccate pollen with granular exine structure
Guard cell mother cell gives rise to a pair of guard cells
One or more pairs of subsidiary cells
Aggregate reproductive structures into flower-like structures
Commonly bisexual
Classification
Classification
└Anthophytes
Geologic Age
Geologic Age
Middle Triassic - present
Above: Anthophyte clade, with representatives: cross-section of a stem of the Pentoxylon (left), Nilssonia, a Bennettitalean leaf (middle), and the flower of an angiosperm, Akebia (right)
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