My very own discovery: Grassy Tarplant has two different seed distribution strategies!

Well, I may not be the first to notice this but... it's always deeply satisfying to make your own discoveries, don't you find?

"What the heck are these little burr things?" I wondered.
I was out in my garden gathering seeds of a nice-enough local wild native called grassy tarplant - or tarweed - or gumplant - choose your favorite common name. It's unequivocally called Madia gracilis in the botanical world.

This is a very branching, bushy form of Madia, less than three feet tall. It's otherwise not that remarkable or garden worthy.

Flowers are small, but instead of being clustered at the top of a huge rather ugly vertical stem (like M. sativa), they are sprinkled along long slender branches (not evident in the photo above, but rather pretty en masse).

I think it'll be perfect for my North Forty, where the farther away the plant, the less garden worthy it has to be (and the more locally native). Hence my seed collecting.

As I was gathering, I noticed some sticky burs on the back of my gardening gloves. See photo at top!

I was puzzled. I hadn't been near any of the usual culprits - chervil or bedstraw etc - and these were a different shape. Finally it twigged - when I saw an extra ring of seeds on all the seed heads I was collecting from!

Yup - those sticking-out bits were sticking to my gloves.

"The "burrs" are actually the phyllary bracts." This I learned - and much more - from botanist John Dittes. He and other knowledgeable people also helped me come up with this plant's ID - I wasn't sure what species of Madia it was - on FaceBook's California Native Plant Society group.

I felt so full of the pleasure of personally discovering something! We can't all be Darwin, but if we are out in nature noticing, we'll all have the chance to make personal discoveries that probably feel as great to us as the discovery of Natural Selection did to him. Well - maybe not quite.
At last gleams of light have come, & I am almost convinced (quite contrary to opinion I started with) that species are not (it is like confessing to a murder) immutable ... I think I have found out (here's presumption!) the simple way by which species become exquisitely adapted to various ends ...  (from Darwin's diaries
Many of us lesser mortals know that in daisy type flowers, each flower head is composed of multiple individual flowers - ray flowers are the "petals" and disk flowers are the clustered centers. But this is the first time I'd noticed that ray flowers can have their own seeds - and that those seeds can have a different distribution strategy from the disk seeds.

Of course, this is a well known thing to botanists, as anyone who looks up the Big Book - The Jepson Manual - conveniently available online - can see. Here's a link to the page for Madia gracilis. It quite casually mentions the ray fruit and the disk fruit.

However, Jepson doesn't mention the burr-like nature of the phyllary bracts. Or talk about the distribution strategies the plant employs in producing two different types of fruits.

What the strategy of the solid little disk seeds is - I can only guess at. Does anybody know? I don't think they would get pooped out like the seeds of a soft fruit. Do they just fall down and gradually the cluster of plants gets larger and larger? I'd love to know.

Madia elegans

Now for those of us who are left feeling thirsty for a bit of pretty - here are two shots of Madia elegans, showy madia, grown in my garden from local wild a couple of years ago...

Madia elegans, showy madia. Still sticky but at least you get nice flowers!

Madia elegans, showy madia. 
If you want to grow Madia elegans, I recommend you prune it back once or twice before it flowers - otherwise it shoots up to a leggy six feet tall, in garden soil anyway!  

Madia seeds are a favorite of the California quail and mourning doves who visit my garden.

Native Americans in California used Madia seeds to make pinole. Interesting details here.

Madia gracilis ID photos

And for those sticking with this post to the very end -- here are a few photos of Madia gracilis in case you want to ID any of these plants yourself...


Diana Studer said…
something in common with our rain daisy. Dimorphotheca pluvialis. Which also has 2 sorts of seeds, flat 'discs' like coins, and why are there all these sticks in my seed packet?
Diana Studer said…
from PlantZAfrica - The seeds are interesting in that two different forms are produced. The ones we usually sow are flat, papery and fly away easily in the wind. They are formed in the center of the flower by the disk florets. The outer ray florets form seeds which looks like little thorns with thick coats. Under favorable conditions the papery seed of the disk florets germinate in abundance, while the seeds of the ray florets have delayed germination to protect the species against unpredictable conditions in their arid environment.
Country Mouse said…
Very interesting, Diana. I know of a few other plants with "back-up" strategies - grasses with seeds way down low in case the upper seeds get grazed off or burned off. Or as in your case - delayed germination, and again in your case - different means of distribution - wind vs I assume - getting stuck into animal fur. Something new to keep an eye out for now I know!
James Kempf said…
Hi Country Mouse,

Great post! It's always fun when you discover something interesting that Nature came up with.

Diana Studer said…
PS if Town Mouse is still reading along - I have 4 varieties of leaf for Cotyledon orbiculata on my July garden post. She inspired me to start a collection ...