Flowers with petals: this character, as it is used here, requires a small explanation. We call 'petals' any element of the corolla lying below the stamens which is brightly coloured (i.e. not green nor brownish) and which serves to attract pollinator insects, including tepals and sometimes petaloid sepals:


Flowers without petals: this character includes flowers which are usually pollinated by wind and lack a well-developed corolla, or which have inconspicuous, usually greenish or brownish petals.

Some examples: Amaranthus:

Atriplex

all species of the Poaceae family:

all species of the Cyperaceae family:

all species of the Urticaceae family:

the species of the genus Euphorbia:

the species of the genus Juncus:

all species of Gymnosperms:

the willows (genus Salix):

other woody plants of different families:


The species of Plantago, whose flowers have membranous, brownish to whitish tepals, can be reached by selecting both the option 'flowers with petals' and the option 'flowers without petals'