In Search of Something Green (and Native)

Posted on January 13, 2016 by elizabeth

American holly (Ilex opaca) on the Cabin John Trail

After two weeks battling a sinus infection, I finally felt well enough to go for a hike. Well, more of a walk. As I’ve written before, the Cabin John Trail is treacherous: an over-used trail with poor footing in many places. But, I almost always find something worthwhile, if I take the time to poke around and really look at things.

And so it was yesterday. I knew I’d find a lot of Christmas fern, but went with the goal of finding something else – and I did, after scrambling about in a dryish seasonal watercourse. Look for a post about that fern in another few days.

After that I went to a section I call Erica Alley. It’s a very rocky slope with a high concentration of mountain laurel (Kalmia latifolia), and big stands of rock polypody. There I found several small stands of spotted wintergreen (Chimaphila maculata, another ericaceous plant), which thrills me because I failed to find it near Carderock this year. And then, poking about, I found something completely new. And something old that required re-inspection.

I don’t carry ID books with me. Whenever I have a book, I end up plopping my butt down and reading for 20 minutes. I’m too easily distracted by “dictionary syndrome”. So I take pictures, but often fail to get the right pictures for a definitive ID. At least I’ve narrowed them down to the correct genus. Perhaps if the weather’s good today I’ll go out again, this time with the ID books, dammit.

If you see a middle-aged woman reading a book on the Cabin John Trail, say hi.

Many Little Feet

Posted on January 7, 2016 by elizabeth

Common or rock polypody, American wall fern, rockcap fern
Polypodium virginianum

a small stand on the Cabin John trail

This little fern is no less charming for being incredibly common. It’s found throughout most of the eastern US and Canada except for parts of the deep south. Although short (the fronds are usually about twelve inches long), the rhizomes will form massive colonies in suitable habitat, which consists of all sorts of rock outcroppings and rocky soils in moist shade.

an itty-bitty specimen at Carderock; it doesn’t have much soil to grow in!

It’s also an easy fern to identify, especially at this time of year, since it’s evergreen.

new fronds in late April along the Cabin John trail

Ebony Spleenwort

Posted on December 30, 2015 by elizabeth

Asplenium platyneuron
new fronds with croziers, May 2015

The day after my last post, I went to Hoyles Mill Conservation Park (in the Little Seneca Creek watershed, near Boyds), hoping to find some evergreen ferns. There was a nice stand of Christmas fern along a bank:

Looking closer I saw a second species: ebony spleenwort. It’s the smaller, lighter-colored fronds on the left in this picture:

At twelve to twenty inches tall, ebony spleenwort is one of the larger members of its genus. It’s wide-ranging, from Quebec south and west as far as Arizona, and can be found in a variety of habitats. Look for it on embankments, rock outcroppings that have a little soil, even old stone fences. It’s listed as special concern in Maine and exploitably vulnerable in New York.

a specimen near C&O Canal lock 8, August 2015

The name “asplenium” is from the Latin, meaning “without spleen”. The specific epithet “platyneuron” can be translated as “flat-nerved”.

underside of a pinna on a fertile frond, showing indusia and sporangia

Several other evergreen ferns can be found in the Maryland Piedmont; I’ll be posting about them in the coming weeks.

Oh, Christmas Fern

Posted on December 25, 2015 by elizabeth

Polystichum acrostichoides
Dryopteridaceae (wood fern family)

specimen showing sterile and fertile fronds; pardon the boot!
——>

If you’ve been walking around the woods during this freakishly warm season, you’ve probably seen Christmas fern, a widespread evergreen fern of moist to dry woodlands that’s found all over the eastern part of North America. It’s a lovely plant for the garden, with glossy dark fronds adding winter interest, and a tidy, clump-forming habit.

young frond in July

Christmas fern stands about two feet tall, and is easily identified (especially in winter). Each pinna has a distinctive upward-pointing lobe near the base, variously described as a thumb, or toe, or ear. (The technical term is auricle, meaning ear-shaped lobe.)

The fertile fronds have a distinctive shape, with the sori-bearing pinna becoming shorter, narrower, and more widely spaced on the upper portion of the fronds:

sori on underside

crozier in July

ps: please refer to my posts about fern terminology and fertile fronds for definitions of some of the jargon

Fertile Fronds (More About Ferns)

Posted on August 7, 2015 by elizabeth

fertile fronds of purple cliffbrake (Pellaea atropurpurea)

So if ferns aren’t flowering plants, how do they reproduce? The answer is fairly technical, and detailed descriptions are only a search away. Here’s a good one. A short answer is: they produce spores rather than seeds. (Although, as with seed plants, there are vegetative means of reproduction as well.)

Spores generally, but not always, form on the underside of a frond. Not all fronds are fertile (that is, spore-bearing). If you look on the back of a fern frond and see lots of little dots, you’re looking at a fertile frond.

The spores are contained within structures called sporangia. The sporangia, in turn, are often (but not always) clustered together in structures called sori (singluar sorus), which are the small dots that you can see with the naked eye. Sometimes the sorus will be covered by a flap of tissue called an indusium (plural indusia).

Noting the characteristics of the sori – how they’re shaped, how they’re placed on the pinnae – can be an important step in identifying the species of fern.

And now, the meat of this post, which I’ve written in part because this stuff is fascinating, but mostly because I’ve been having fun taking “studio” pictures.

the reverse side of purple-stem cliffbrake; in the lead-in photo, the white margins on the pinnae are a clue that the fronds are fertile (an unusual characteristic)

linear sori along the midveins of the pinnae on ebony spleenwort (Asplenium platyneuron); some indusia are also visible near the rachis

orbicular sori along the margins of the pinnae of common polypody (Polypodium virginianum)

marginal woodfern (Dryopteris marginalis)

closeup of marginal woodfern

the unusual fertile frond of rattlesnake fern (Botrypus virginianus)

linear sori scattered along the frond of walking fern (Asplenium rhizophyllum)

blunt-lobed cliff fern (Woodsia obtusa)

masses of sori on christmas fern (Polystichum acrostichoides)

Elizabeth's Wildflower Blog

hunting in the Maryland piedmont (mostly)

Tag Archives: ferns