Dating dispersal and radiation in the gymnosperm gnetum Webcam pornochat

Molecular phylogenies based on nuclear and plastid sequences from most of the species indicate hybridization among some of the Southeast Asian species.

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This was the first known instance of horizontal gene transfer between higher plants; it only affects an Asian clade of Gnetum; and molecular clock reasoning suggests that it happened only about 2 to 5 million years ago.

Won and Renner (2003) revealed the startling news of horizontal gene transfer of mitochondrial DNA from Petunia to Gnetum.

Both male and female megastrobili terminal or lateral, sometimes arranged in dense, cauliflorous clusters on old stems. Gnetum arboreum Foxworthy is restricted to a small portion of Luzon, Philippines (Markgraf 1930, in Carlquist 1996b).

Leaves opposite, petiolate, without stipules, simple, elliptic, with pinnate veins and entire margins; usually with drip tips. microcarpum Blume, Gnetum montanum Markgraf, and Gnetum ula Brongniart.

The female strobilus bears a droplet of sugary, sticky fluid that in time retracts into the strobilus, carrying any captured pollen grains to the nucellus.

This unusual mechanism works best in high humidity settings and has been suggested as one reason why Gnetum is restricted to rainforest habitats.

Unlike other gymnosperms, they possess vessel elements in the xylem.

Some species have been proposed to have been the first plants to be insect-pollinated as their fossils occur in association with extinct pollinating scorpionflies.

Relationships among Gnetales and the other seed plant lineages are still unresolved, and we therefore used differently resolved topologies, including one that contained a basal polytomy among gymnosperms.

For a small set of Gnetales exemplars (n = 13) in which rbc L and mat K satisfied the clock assumption, we also obtained time estimates from a strict clock, calibrated with one outgroup fossil.

Living gymnosperms represent the survivors of ancient seed plant lineages whose fossil record reaches back 270 million years.

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