TY  - BOOK
AU  - Clausen, Jens
TI  - Stages in the Evolution of Plant Speecies
U1  - 580 
PY  - 1951///
CY  - New York
PB  - Cornell University Press
KW  - General Stack
KW  - EVOLUTION OF PLANT SPEECIES
KW  - PLANTS
KW  - Botany
ER  -