Journal archives for February 2022

February 15, 2022

Pin and thrum heteromorphy in Lycium exsertum

Some time ago @emaking introduced me to pin and thrum floral heteromorphy, in which either male or female flower parts in normally perfect flowers are alternately suppressed. Lycium exsertum and its cousin L. fremontii exhibit heterostyly; some of them are functionally dioecious. All flowers of an individual shrub are either:
1) Perfect - male and female parts well-developed
2) Pin flowers with short filaments, reduced anthers and a normal pistil producing functionally female flowers
3) Thrum flowers with short pistil length and anthers large and well-exserted resulting in functionally male flowers

I ran a short survey of the L. exsertum plants on my property, 33 plants, all in flower. Of those, 7 have perfect flowers, 12 have thrum flowers and 13 have pin flowers. Pin flower corollas were generally smaller than perfect and thrum flowers, both shorter and narrower. In addition there was one plant expressing poor development of both male and female parts, representing a fourth condition to add to the list above.

Posted on February 15, 2022 10:06 PM by stevejones stevejones | 1 comment | Leave a comment