Conifers can produce multiseriate rays if the rays contain resin canals, and Gnetales
are all characterized by multiseriate rays.
, Cambridge University Press, London, UK, 1929.
Keywords: Chhidru Formation, Palynomorphs, Monocolpate, Sulcate, Gymnosperms, Peltasperms, Gnetales
, Medullosales and Ephedralels.
Xylem hydraulic and photosynthetic function of Gnetum (Gnetales
) species from Papua New Guinea.
Phylogenetic relationships in Ephedra (Gnetales
): evidence from nuclear and choloplast DNA sequence data.
Several previously mentioned studies have used various gymnosperm groups (particularly the Gnetales
) as outgroup.
Conifers and most members of the Gnetales
(i.e., Ephedra and Welwitschia) express both prefertilization and postfertilization provisioning of embryo-nourishing tissues of the female gametophyte (Martens 1971; Singh 1978; Haig and Westoby 1989).
Pollen chambers are known from the earliest fossils of Gnetales
(Rothwell & Stockey, 2013).
Structure and function of female and bisexual organ complexes in Gnetales
. The International Journal of Plant Sciences 157: S113-S125.
Orbicules are omnipresent in Gnetales
: Ephedra (El-Ghazaly & Rowley, 1997; Doores et al., 2007), Gnetum (Camiel, 1966), and Welwitschia (Zavada & Gabarayeva, 1991).
What Brown most importantly recognized, albeit in a somewhat circumlocutious way, was that in cycads, conifers and Gnetales
, among extant seed plants, the ovules receive pollen directly, whereas in flowering plants the ovule, being enclosed within a carpel, cannot receive pollen, that being the function of the stigma.
Rudall is doubtful that the monocot cambium is equivalent to secondary thickening meristematic activity in non-monocot angiosperms and Gnetales
, and indeed, it is not.