Table 1.

Comparison of fleshy ovule/seed structures in genera of Taxaceae

Fleshy structure (aril)	Austrotaxus, Pseudotaxus, Taxus (APT group)	Amentotaxus, Cephalotaxus, Torreya (ACT group)
Attachment	Aril free, cup-like (not strongly fused to the ovule)	Aril strongly fused to the ovule
Early development and growth	Development initiated by two lateral primordia with mostly apical growth; subsequently a ring primordium is formed (Austrotaxus unknown)	In Amentotaxus and Cephalotaxus, growth commences with a ring primordium, and is intercalary (though there are few data on Amentotaxus). In Torreya, an initial distal growth phase forms two free distal lobes; subsequently a ring primordium is formed, with an intercalary growth phase.
Epidermis	Papillate	Non-papillate
Anatomy	Internal tissues lacking large intercellular spaces	Internal tissues with several large, vertical intercellular spaces
Vasculature	Absent	In Torreya, two vascular strands are present; in Amentotaxus absent; in Cephalotaxus they are probably absent (based on images in Mundry, 2000)