Dictionary.com
Thesaurus.com

monosepalous

American  
[mon-uh-sep-uh-luhs] / ˌmɒn əˈsɛp ə ləs /

adjective

Botany.
  1. gamosepalous.

  2. having only one sepal, as a calyx.


monosepalous British  
/ ˌmɒnəʊˈsɛpələs /

adjective

  1. (of flowers) having only one sepal

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of monosepalous

First recorded in 1820–30; mono- + -sepalous