622 PHARMACEUTICAL BOTANY 
Chief among these carnivorous plants are the sundews, fly- 
traps, pitcher-plants, bladderworts and butterworts. In each 
it is the leaves which have become modified for the purposes 
indicated. 
Dead 
Organisms 
“Bacterial . 
; Decay... 
Carbohydrates. 
Plant proteins 
Fats 
Products 
a 
Fic, 472.—The carbon cycle. (After Gager.) 
Intermediate 
Decomposition 
Tue SuNDEWS 
The sundews are curious, small, bog plants that are mainly 
members of the genus Drosera which comprises 84 species, occur- 
ring in tropical, warm temperate and cool temperate regions of 
both hemispheres. Each of these possesses a rosette of leaves 
that arise from a greatly reduced root system. The shape of the 
leaves varies depending upon the species, although it is fre- 
quently rotund, spatulate or filiform. The whole upper surface of 
the leaf-blade is covered with glandular tentacles often of a wine- 
red color. The glandular heads of these are covered with a 
viscid secretion that glistens in the sunlight like dewdrops, a 
phenomenon that accounts for the common name assigned to the 
members of this group. The tentacles in the central part of the 
leaf-blade are short and erect and their stalks are green. Toward 
the margin they become longer and more inclined outward and 
their stalks are of a wine-red to purple color. 
