Partition tables / Output of parted

[Stefan Malte Schumacher <s.schumacher@netcologne.de>]

Hello

I have created multiple filesystems with btrfs, in all cases directly
on the devices themself without creating partitions beforehand.  Now,
if I open the disks containing the multi-device filesystem in parted
it outputs the partion table as loop and shows one partition with
btrfs which covers the whole disk. Opening the disk with the
single-device fileystem in parted shows a partion table, type unknown
and no partition on the disk itself. 

I am unsure how to interpret this output. Two possible explanations
come to mind: a) Btrfs does create partitions, but only if a filesystem spans
multiple devices or b) the output of parted is faulty and no actual
partition is created in both cases. 

Could someone elaborate on this question or just point out where I can
find documentation on this issue?

Yours sincerely
Stefan