Seeeduino V3 uses FTDI USB to Serial chip which is supported by Ubuntu and other GNU/Linux since many versions. We checked in Ubuntu 14.04 and it works.
If you use sudo to start arduino application as suggested, it must work without even adding user to dialout group.
- Reconnect the Seeeduino V3
2)Use lsusb to check FTDI chip is listed (this ensures that the USB cable is fine.
3)check if the new COM port is listed in /dev/ folder as ttyUSB*
4)Start Arduino in Sudo mode and select the appropriate port.
P.S: Sorry for delayed reply. This solution must help other users as well.