Some plants have really unusual features.  This edible crop and weed, purslane (Portulaca oleracea), has capsular fruits with a top that 'pops off', so that the seeds are then exposed to weather and wind.  This particular type of capsule is called circumscissile, and for this particular plant is could be that the part that is left below with the seeds functions as a splash cup.  I don't know, but it is not unlikely.  The little black seeds would then splash out of the cup when a raindrop hits the cup, and disperse further than just normal falling down out of the capsule. (Note to myself, research needed!)   

Splash cups are not that common, but also occur in the bird's-nest fungus. While looking up purslane I found out that one plant can produce more than 240 000 seeds per season.  Well, it is good it is edible then.

You can read more about purslane and this photo here. 

Photo credit (c) Arjo Vanderjagt on Flickr

Species: purslane (Portulaca oleracea, Portulacaceae)

Seeds Flying Away

Seeds Flying Away, a photo by Lauren Tucker Photography on Flickr.

A photo showing the very efficient fruit dispersal by wind of thistles, which are relatives of dandelions. Both are the sunflower family, Asteraceae.

In the news: Survival of agricultural weeds

A press release on ScienceDaily summarizes a new study comparing how long seeds from two species of weeds (Chenopodium and Amaranthus, Amaranthaceae) survive under conventional vs. organic farming:

Organic and conventional farming methods compete to eliminate weed seeds in soil

The answer: no strong conclusion either way, the result is mixed. Here is the original article: LINK (doi: http://dx.doi.org/10.1614/WS-D-10-00142.1)

Richard Mabey's book reviewed in NY Times

The book WEEDS: in Defense of Nature’s Most Unloved Plants by Richard Mabey is reviewed in New York Times today.  It is great review, but once again there is a common mistake in how evolution works by the writer of the review (and maybe also by Mabey, I am not sure since I haven't read the book yet):

"One can’t help being impressed by weeds’ ingenuity. They’ve grown hooks, burrs, spines, rib hairs and a sort of glue to move their seeds around."

Weeds haven't grown these things.  Plants that had these characters, evolved from genetic variation and mutations over a long time, became weeds because of them.  To become a weed is a secondary thing, not something that forces a plant in a certain evolutionary direction.  

It is interesting though how our weed project hits exactly the same notes as Mabey's book.  History, culture, biology, medicine, and the misunderstood weeds connecting it all.