Pin (a, c, e, g) and thrum (b, d, f, h) pollen grains of Primula

P. allionii measurements detected in thrum (a) and pin (b) flowers

Forsythia - Trees and Shrubs Online

Evolution SpringerLink

a–f. Scanning electron micrograph (SEM) images of acetolysed pollen

Biological Flora of the British Isles: Primula vulgaris Huds. (P. acaulis (L.) Hill) - Jacquemyn - 2009 - Journal of Ecology - Wiley Online Library

Pollen grains on, and pollen tube growth within a LSstigma and pistil

IJMS, Free Full-Text

Long stigma flower hi-res stock photography and images - Page 6 - Alamy

IJMS, Free Full-Text

Plants, Free Full-Text

Hypericum aegypticum - Wikipedia

Distribution of pollen grains in the bill of a Copper-rumped

Pin-eyed and Thrum-eyed Primrose Sheffield city nature diary by Penny Philcox

Bloom of the Week - The Heterostyly Supergene Identified