[1] : The Collaborative International Dictionary of English v.0.48

clematis \clem"atis\ kle^m".ati^s, n. nl., fr. gr.
   klhmati`s brushwood, also from its long, lithe branches
   clematis. fr. klh^ma twig, shoot, fr. kla^n to break off.
   bot.
   a genus of flowering plants, of many species, mostly
   climbers, having feathery styles, which greatly enlarge in
   the fruit; -- called also virgin's bower.
   1913 webster
see also:
virgin's bower 

[2] : WordNet (r) 2.0

clematis
     n : any of various ornamental climbing plants of the genus
         clematis usually having showy flowers

Clematis >> C Words
Clematis, definition of term: Clematis
clematis_pag1.html