The Aster Family (part 4)

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Tragopogon (goatsbeard) species (I think)

 

 

Each floret of a composite family plant produces a single fruit (which contains a single seed) called a cypsela. In many texts and on-line sources, the term achene is used. The difference between the two is technical (it depends on the position of the ovary), and for years both were used rather loosely. While trying to make sense of this I tripped over an article in the Brazilian Journal of Botany, the poorly translated abstract for which reads

The worry about the indiscriminate use of the terms cypsela and achene for the fruits of Asteraceae has been frequently detached by specialists in this family. The present work was developed aiming to verify the existence of arguments to justify the adoption of a term against the other. After historical and anatomical analysis, we concluded that there is technical basis to consider cypsela and achene as different types of fruits. For Asteraceae, the correct is to call cypsela; achenes are only derived from superior ovaries, as in Plumbaginaceae.

At any rate, picture a single small seed with a tuft of hairs, like dandelions have.

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Erechtites hieracifolius (pilewort)

 

 

That’s pretty much it, unless there are barbs instead of hairs:

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Bidens bipinnata (Spanish needles); note the capitulum (flower head) with yellow ray and disk florets at top, another flower head showing the phyllaries in the middle, and the barbed cypsela at the lower right

 

 

next: lower classifications

Almost Done

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A few asters, goldenrods, and eupatoriums are hanging on, but mostly the wildflower show in the Potomac Gorge is done for the year.  That means it’s time to watch for other interesting things, like autumn leaves, the shapes of bare tree branches silhouetted against the sky, foggy sunrises and clear sunsets.  And seeds.  Like these seedpods of common milkweed (Asclepias syriaca) that were just opening on the riverbank near Lock 8 in mid-October.

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just opening, not puffed out yet

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forming little balloons

 

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freedom!

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milkweed in early June20150610-20150610-_DSC0089

Seeds

Call me a snob, but I’m just not interested in invasive alien plants.  I’d rather see a tiny, subtle native than a big, splashy exotic.  But there are times when they have their charms.

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Like when this yellow goat’s beard (Tragopogon pratensis)
went to seed.

June 7

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June 16

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photographed at Belmont Manor and Historic Park, Howard County, Maryland

More Seeds

Milkweed (Asclepias).  Didn’t see the plant in flower, so I can’t say which species.  October 28, Shenandoah National Park, parking lot at Riprap Hollow trailhead.

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closeup of seeds

 

 

 

 

 

 

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unripe pods not quite ready

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fly!  be free!

 

 

 

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I just love how they form little balloons as they’re getting ready to go…

 

 

 

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…and embrace the sky

Seeds

Flowers may be done blooming, but some plants are still beautiful.

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These three pictures are of fireweed (Chamerion angustifolium), which I found in Nova Scotia and New Brunswick this past September.  As you can see, it was already done flowering, but I couldn’t resist taking some close-up shots of the seeds.

Fireweed is in the evening primrose family (Onagraceae); it’s found in Canada and a few northern US states. 20140913-DSC_0186