32bit -current+XFCE+usb stick=no automount

-the user is a member of all the required groups.
-usb stick automounts correctly on my machine which the same version, kernel level etc.
#lsblk shows
root@hera:/home/prof# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 55.9G 0 disk
|-sda1 8:1 0 500M 0 part /
|-sda2 8:2 0 500M 0 part [SWAP]
|-sda3 8:3 0 8.3G 0 part /usr
|-sda4 8:4 0 1K 0 part
|-sda5 8:5 0 1.5G 0 part /opt
|-sda6 8:6 0 43G 0 part /home
|-sda7 8:7 0 750M 0 part /var
`-sda8 8:8 0 1.5G 0 part /tmp
sdb 8:16 1 7.2G 0 disk
`-sdb1 8:17 1 7.2G 0 part
sr0 11:0 1 1024M 0 rom

#lsusb shows
root@hera:/home/prof# lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 005: ID 090c:1000 Silicon Motion, Inc. - Taiwan (formerly Feiya Technology Corp.) Flash Drive
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

trying to mount gives
root@hera:/home/prof# mount /dev/sdb
mount: can't find /dev/sdb in /etc/fstab
root@hera:/home/prof# mount /dev/sdb1
mount: can't find /dev/sdb1 in /etc/fstab
root@hera:/home/prof#

I probably can't see this for looking at it. Clues happily read!