windows - Why when I retrieve the list of partitions it only gives me one result?

When I type
sudo fdisk -l

it just gives me 1 partition (I have 2 partitions for Ubuntu and Windows 7).

See the full result:

Disk /dev/sda: 320.1 GB, 320071851520 bytes
255 heads, 63 sectors/track, 38913 cylinders, total 625140335 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x2b15104e


Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048   625137663   312567808    7  HPFS/NTFS/exFAT

I think this is the Windows 7 partition.

Note: I installed Ubuntu using the Wubi installer for Windows.