6LoWPAN or ZigBee better?

Hi, Can a Galileo running the Contiki OS (which supports 6LoWPAN) use XBee (Series 1) and connect to the Internet directly without requiring a Gateway device... but I guess Meshing won't be supported.. Or is it preferable to use XBee Series 2 (which uses ZigBee instead of 6LoWPAN in layer 3) connected to the Galileo and use a Gateway device? Without ZigBee all nodes will be able to communicate only with the central coordinator, am I right?