TY  - BOOK
AU  - Clausen,Jens
TI  - stages in the evolution of plant species / 
U1  - 581.38 CLA 
PY  - 1967///.
CY  - New York : 
PB  - Hafner Publishing Company, 
KW  - Evolution - plants
KW  - Planten
KW  - Soortvorming
ER  -