Annona rigida

Annona rigida is a species of plant in the family Annonaceae. It is native to Brazil and Colombia. Robert Elias Fries, the Swedish botanist who first formally described the species, named it after its rigid (rigidus in Latin) leaves.

Description
It is a bush. Its rigid, oblong, yellow-green leaves are 12-20 by 3-5 centimeters, hairless and have pointed tips. Its solitary flowers are on thick, rigid pedicels that are 0.5-1 centimeter long with a 3-5 millimeter oval bract near their base. Its oval to triangular sepals are 4-5 millimeters long, recurved and come to a point at their tip. It has two rows of petals. The oval, wrinkled, warty outer petals are 3 by 2 centimeters. The outer petals have margins that touch but are not fused. The outer surface of the inner petals is covered in dense woolly hairs. Its stamen are 5 millimeters long. Its immature fruit are round with a diameter of 2–3.5 centimeters and covered in conical projections. Its flowers have numerous carpels.

Reproductive biology
The pollen of A. rigida is shed as permanent tetrads.

Distribution and habitat
It grows in the Amazon rainforest.