Weakley Flora to the Rescue! (With a Primer on Using Botanical Keys)

upper stpem, leaves, and inflorescence

upper stem, leaves, and inflorescence

The day after writing the previous post, I returned to Serpentine Barrens Conservation Park armed with a 10X lens, a small knife, a ruler, a notebook, and most important, a printout of page 1126 of the Flora of the Southern and Mid-Atlantic States by Alan S. Weakley, determined to key out my unknown goldenrod species.

Success! I keyed it out in the field, but collected a sample to photograph at home with the macro lens.

If you’re interested in how botanical keys work, keep reading. If you just want to know which species it is, skip to the end.

The first couplet in Weakley’s key reads:

1  Leaves with numerous slightly raised, pale, translucent, blister-like pustules; leaves transmit light when held up; plant glabrous………E. leptocephala
1  Leaves without pale pustules, or if present then leaves opaque and do not transmit light; plants glabrate to pubescent.

Glabrous is smooth, glabrate means “almost smooth”, and a pubescent area is covered in short hairs.

closeup of stem and leaf base showing hairs

closeup of stem and leaf base showing hairs

 

Have a look at this photo. Clearly the plant is hairy, so I chose the second line, which leads to this couplet:

 

 

 

2  Major veins on leaf underside 3-5 (if 3 then all 3 veins bold), leaves 5-12 mm wide; heads with 20-50 flowers.
2  Major veins on leaf underside 1-3 (-5) (if 3 or 5 then only the midvein bold), leaves <6 mm wide (-8 mm wide in E. gymnospermoides); heads with 10-20 flowers.

leaf base, underside

underside of leaf at base

In the field I measured the largest leaves that were still intact on the plant. (All the lower, presumably largest, leaves had turned brown and curled up and many had fallen off.) Most of them were in the 7-8 mm range. Every leaf I examined had five veins, though some were pretty hard to see. Given these facts, I chose the first line of couplet 2 (more about the flower heads later), which leads to

3  Leaves 3-6 (-8) mm wide, punctae on leaf upperside bold, flower heads 10-20 flowered………..E. gymnospermoides
3  Leaves 5-12 mm wide, punctae on leaf upperside obscure or not bold, flower heads 20-50 flowered.

Again based on leaf width, and the fact that the punctae (dots) were not bold, I chose the second line, which leads to

4  Leaf undersides, upper stems, and branches glabrate, often with villous hairs on midrib of leaf underside …………………E. graminifolia var. graminifolia 
4 Leaf undersides, upper stems, and branches copiously to moderately short villous
…. E. graminifolia var. nuttallii

Look at the first picture again; I’d call that copiously villous. (“Villous” means covered in soft hairs.)

flower heads (7/32" long)

flower heads (7/32″ long)

About the flowers… Remember that plants in the Asteraceae have composite flowers. That little thing next to the ruler in this picture, measuring only about five and a half millimeters long, is a flower head – a collection of flowers. At least, it was, as these had all turned to seed. I was able to cut some open and tease out the seeds. I didn’t count more than 20 in any single head, which suggests about 20 flowers (each flower produces one seed). But, they were minute, and I was working with a small knife and a 10X hand lens, so it’s quite likely my count was inaccurate. Since I couldn’t get a true count of flowers per head, I ignored that part of the key.

seeds

seeds

So there it is. My mystery grass-leaved goldenrod/goldentop is Euthamia graminifolia var. nuttallii.

Two Years Old

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Happy 2nd Birthday to my blog! I’m celebrating by changing the look. Also by upgrading the account. OK, actually it’s not celebrating; I’ve uploaded so many pictures that I ran out of space, so I had to upgrade.

young fronds of ebony spleenwort

 

I’m also celebrating by re-posting some favorite photos.  Enjoy.

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wild stonecrop

 

 

 

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partridgeberry

 

 

 

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flowering dogwood

 

 

 

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enchanter’s nightshade

 

 

 

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miterwort

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lopseed

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cranefly orchid

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purple-headed sneezeweed

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bee leaving goldenrod

 

 

Back to regular blog posts tomorrow!

Farewell for Now

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The weather’s getting colder [actually not, we’re having an unusual warm spell], the leaves are off the trees, the perennial wildflowers are dormant: the season is done. And so is this blog, for a little while. I’ll make an occasional post if I find something interesting or lovely while out and about, things like plants going to seed or nice landscapes. I’ll post the Three Views shots in early December. And probably some time in early March I’ll be out again looking for harbinger-of-spring to emerge, and the blog will re-emerge, too. Farewell for now!

 

above: bumblebee departing riverbank goldenrod

below: sunset on the Potomac near C&O Canal Lock 8, October 20

bottom: harbinger-of-spring last March

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Silverrod

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aka white goldenrod
Solidago bicolor
Asteraceae

This is one of only two species of Solidago that isn’t golden, though if you look closely you’ll see that the disk flowers are often pale yellow while the rays are white.

Confusingly, the other white flowering species is called upland white aster, but despite the common name is actually a goldenrod, Solidago ptarmicoides.

Silverrod is a plant of the eastern US and Canada that ranges as far west as Missouri, Quebec in the north, and south to the Gulf Coast (but not Florida).  It’s a low-grower, seldom exceeding two feet, and prefers drier soils in open woodlands.

I never have managed to get a really good picture of it, for some reason.

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Not Quite a Drought

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the narrow channel between Billy Goat B and Offutt Island; the river is really low – all the land in this picture should be underwater

After three weeks’ absence I eagerly hit the Billy Goat B trail yesterday, expecting to find a lot of asters and goldenrods.  What I actually found was a whole lot of nothing.

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that is one sad looking maple

OK, not really nothing, of course.  And although we are not yet officially in a drought, we are abnormally dry here.  As a result, the wildflower show is really muted.  Plants are going dormant early, their leaves wilted or brown (at least, I hope they’re going dormant, and not dying).  Many trees have lost their leaves already, and others’ leaves are turning brown

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this black walnut isn’t too happy, either

I saw plenty of white snakeroot, which is dominant at this time of year regardless of weather, a fair amount of wingstem, several different species of goldenrod, a few silverrods budding up, a few scattered asters, one plant in the genus Bidens, and that’s about it.

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look at all the brown plants behind this smooth aster

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that’s a sorry looking wingstem, but the bumblebee doesn’t seem to mind

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riverbank goldenrod says “what is drought?”

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calyces on bugleweed

Flower of the Day: Silver-rod

Soldago bicolor; Asteraceae (aster family)

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That’s right, another goldenrod.  Except this Solidago has white flowers (it’s the only one that does), therefore silver-rod.  I found it the morning after returning from Montreal, blossoms just opening on a few plants, but dozens more plants almost ready.  With any luck they won’t be finished blooming when I get back from my Nova Scotia trip… If they aren’t I’ll get some better pics and write a proper FotD post.