Introduction

^{(Photo = Gymoncalycium mihanovichii flower, Mike Keeling)}

When sepals and petals seem alike, or grade into one another, you’ve got tepals.

The Details

Cacti have tepals, which  are petal-like and sepal-like parts. Tepals are the outer parts of a flower, but  the inner tepals look like petals and the outer tepals are where the sepals should be. Usually there is no set number of tepals–a flower might have 40 and the next flower on the same plant might have 43. Other plants have a set number of petals and sepals. For instance, mustard flowers always have four petals and four sepals, no more and no less.

Additional Reading: Flower Parts

Outer tepals are pink and green–half petal and half sepal, Scott Nelson, 2011

Cactus flower bud with tepals, RatDog Ace

Cactus flower with tepals, BoopQ

Cactus flowers with tepals, the outer ones almost seem like sepals, Jack Haslek

Cactus flower with tepals, the outer ones look almost like sepals, Omar Lanz

Cactus flower bud with tepals, David

Cactus flower with tepals, Melissa Bowersock