monopetalous

A shrub with monopetalous, stillated, purple flowers, growing in tufts.
The History of Sumatra|William Marsden
They are monopetalous, small, white, stellated in six points.
The History of Sumatra|William Marsden
Trifolium with a monopetalous flower, of a white colour, (T. pratense).
Lachesis Lapponica|Carl von Linn
The pistil is also very curiously formed, as the style and stigma have the appearance of a gaping monopetalous corolla.
Botany for Ladies|Jane Loudon

This was the case with a poppy, which had become monopetalous by the union of its petals.
The Variation of Animals and Plants Under Domestication, Volume II (of 2)|Charles Darwin

British Dictionary definitions for monopetalous

monopetalous

/ (ˌmɒnəʊˈpɛtələs) /

adjective

(of flowers) having only one petal

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