Bell, C. Ritchie <br/><br/>
Plant variation and classification 
by C. Ritchie Bell ; drawings by Susan Carlton Smith 
 - London  MacMillan  1964 
 - vi, 135 p. : ill. ; 22 cm. 
 - Fundamentals of botany series .
<br/><br/>p. 121-125. 
<br/><br/><label>LCCN: </label>67-014787 //r85 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Botany--Classification<br/>Botany--Variation