Style Position

A feature of primulas is their heterostyly nature. Almost all Primulas have a pin form (where the level of the stigma is above the anthers) and a thrum form (where the level of the stigma is below the anthers).

Thrum and Pin forms of Primula polyneura

 

Pin and thrum forms of Primula polyneura

As such, this wouldn’t then be something that would distinguish a species, but a few species are homostylous – that is the stigma and anthers are at the same level. There are long homostlye and short homostyle forms with the level of the stigma and anthers correspondingly high or low in the flower.

Homostyle Primula cuneifolia subsp. saxifragifolia

Homostyle Primula halleri

Examples of Primula homostyle species include: P. simensis, P. cuneifolia subsp. saxifragifolia, P. grandis, P. dumicola, P. klaveriana, P. septemloba, P. homogama, P. hookeri, prenantha, P. annulata. Some species can have heterostylous and homostylous forms including: P. obconica, P. chungensis, P. cockburniana, P. prolifera, P. halleri.