The plant body in phaeophyceae is usually attached to the substratum by a

The plant body  of phaeophyceae is usually attached to substratum by a holdfast and has a stalk (stipe) and leaf like photosynthetic part called frond or lamina, so brown algae are known as leafy algae. 

Pili and Fimbriae are also surface structures of the bacteria. They do not have a role in motility.  They are known to help bacteria to attach to rocks in streams and also to the host tissues. 

True roots are found in pteridophytes, gymnosperms and angiosperms