Anthophyte clade
Angiosperms and their gymnosperm sister groups
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
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
Syndetocheilic stomata
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
└Anthophytes
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)