seed morphology

The archive of the day is #germination

Click the gif to learn about the process of germination--in nature and in horticulture–including seed morphology, the soil seed bank, seed distribution by animals, seed processes like stratification and scarification, and seed dormancy strategies involving wildfires!

This is what a real geranium looks like

Those rows and rows of multi-coloured annual bedding plants that are called ‘geraniums’ in temperate-zone commercial nurseries are – botanically-speaking – actually from the genus Pelargonium.

The genus Geranium consists of 422 species that look more like the plant pictured above. Many of these are perennial, and have the common name “cranesbill,” referring to the morphology of their unique seed capsule and dispersal strategy.

flickr.com
Double embryo
By the Royal Tasmanian Botanical Gardens on Flikr: "Germinating seed of Euonymus cornutus with unusual double embryo. Double embryos are met very infrequently, in a variety of species, by seed bank workers. Usually however the "twins" lay alongside each other. Having embryos at polar opposites is very peculiar."

Dr. Wolfgang Stuppy comments: ‘Very interesting indeed! Multi-embryo seeds are encountered in Viscaceae but are the product of several developing seeds melting into each other, as far as I know. True polyembryony is however common in Citrus spp. Apomictic plant species may produce somatic embryos from cells of the nucellus and those may indeed develop contrapolar.’


More on polyembryony

kookabugger  asked:

Seed morphology is fantastic, some natives here in Australia require fire for the seed pods to open and germinate.

It’s the same in Canada! Many forests are dependent on fire for renewal: the Parks Department has started doing controlled burns in the last few decades to mimic these wild processes.

Pines (and other conifers) in the Northern Hemisphere often have cones that won’t open without the presence of heat: particularly pioneer species.

The seeds are stored in closed (“serotinous”) cones for many years until an environmental cue triggers the cones to open, releasing the seeds. The most common form of serotiny is pyriscence, in which a resin binds the cones shut until melted by a forest fire.

I’m reading that in the Southern hemisphere, it is most often occurring in the taxa ProteaceaeEucalyptus (Myrtaceae) and Erica (Ericaceae).