Last week brought us to western Ohio where we learned about calciphiles, or lime-loving plant species, and this week as promised our adventures led us straight in the opposite direction to Deep Woods Preserve in Eastern Ohio’s Hocking County. As you may recall from last week’s post (and the first sentence of this post) some plants have special substrate preferences. Jane Fortsyth’s article didn’t stop at the lime-lovers, and the first part of our trip recap dives into their equal and opposite: the sandstone-loving acidophiles.
Substrate-Associated Plants
Chestnut Oak (Quercus montana)
You may think you recognize this tree from last week’s scouting but don’t be deceived. While very similar to the Chinquapin Oak over in Battelle Darby, this Chestnut Oak exhibits lobes that are much more shallow and rounded/wavy as opposed to the sharper Chinquapin margin. The leaves have a leathery texture and like other oaks, they have alternate arrangement and simple complexion. A wonderful addition to the page as well as a great start for our acidophile list.
Sourwood (Oxydendrum arboreum)
No, this species doesn’t have an attitude problem, its name actually comes from the taste of its leaves, which many of us on the hike opted into sampling! While not quite lemony nor citrusy in flavor, I would try it again, if not for any reason other than to have an excuse to safely eat another leaf straight from the source and feel at one with my primitive ancestors. I also think that some kind of tea or herbal drink would be fantastic with these leaves. Its leaves have an elliptical shape a slight toothing/serrate margin, and an alternate arrangement. Perhaps the tart flavor has ties to being an acidophile, but the chemistry of that is a little beyond this blog page.
Eastern Hemlock (Tsuga canadensis)
The Eastern Hemlock pictured above is our third and final focal species for the acidophiles, but last most certainly doesn’t mean least as these trees dominated certain areas of our trek. When we came across any of these pockets of trees, it felt like a whole new environment largely because of their barren understory. That’s thanks to how great the Eastern Hemlock is at blocking out the sun, in addition to preferring cool most areas like in steep ravines. The ground level plants don’t stand much of a chance when it comes to these acidophiles.
Ferns
Arguably one of the most distinct plant families, the fern has many quirky characteristics that help a novice botanist identify who exactly they’ve found (species wise that is). To help with some of these confusing terms and subtle difference I’ve gone ahead and complied a short list of three friendly ferns that were observed on this week’s outing.
Christmas Fern (Polystichum acrostichoides)
Somebody startup Mariah Carey’s seasonal hit (and then immediately pause it because we’ve still got 3 months until Christmas). This festive fern has a frond type that is holodimorphic and a frond dissection type that is twice pinnate. The alliteration combined with new vocabulary might make that sentence both confusing and a sort of tongue twister, so don’t worry because a deeper explanation approaches! Frond type is all about the birds and the bees but for ferns (firds and the fees?). The future of a fern comes from its sporangia which can be found in one of three styles; holodimorphic, hemidimorphic, and monomorphic. Those words are big and scary but all they really mean are ‘separate fertile/sterile parts’, ‘separate fertile/sterile leaves’, or ‘no difference in fertile/sterile location’. So that’s half the battle, the other half is frond dissection type, which is similar to leaf arrangement but for ferns. They can be pinnate, pinnatifid, or pinnate-pinnatifid. The same way pinnately compound leaves on a tree have an extra degree of branching that’s how pinnate works with ferns. Pinnatifid is when the fern looks like the leaves are all separated, but a closer look at their bases actually reveals that they aren’t quite each a single leaflet. Pinnate-pinnatifid is the combination of these two effects, and in addition to those three groupings you can also have bipinnate fern frond dissection types, so the possibilities get more numerous than you may initially think! Back to what I said before now that your brains have grown three sizes with all that new info, holodimorphic and twice pinnate. The sori of these ferns are on the end leaflets of fertile fronds (and for sterile fronds…well they’re sterile). Take special note that the leaflets are in fact separated at their bases!
New York Fern (Thelypteris noveboracensis)
This fern might be named for a different state (or was it named after the city? I guess we’ll never know) but it’s found in states other than New York. Luckily for us Ohio is one of those states, and as you can see above this fern looks a little different than the holiday oriented starting species (I think different in a cooler way). The frond dissection type is pinnate-pinnatifid meaning it’s got branching leaves made of almost separate leaflets, but this is a great example from the explanations above. And you don’t need to look for any fertile or sterile uniqueness because this fern is monomorphic, so it’s sori (gametophytes) are found on the undersides of the plant with no special leaflets or plant type.
Cinnamon Fern (Osmundastrum cinnamomeum)
Our final fern is a bit of a trickster as if you’re not looking closely you may incorrectly categorize its frond/dissection type. The leaves are almost fully divided, but not quite making this…(you should know by now) pinnate-pinnatifid! And these ferns keep the reproductive parts on entirely separate plant parts, so its holodimorphic just like our Christmas Fern.
The Appalachian Gametophyte
Vittaria appalachiana, also known as the Appalachian Gametophyte, is one of the few fern species that is found exclusively as a vegetative reproducing gametophyte. Its range is limited to the eastern United State plateau and Appalachian Mountains, often close to water such as the moist outcrops we found our specimen. As you may know (or may be about to learn) the fern life cycle consists of two main components, the long-lived sporophyte phase and the typically short-lived gametophyte phase. The astonishingly interesting thing about Appalachian Gametophyte is it lacks a mature sporophyte counterpart (at least as far as modern science has been able to find, but maybe that’s where the next generation of botanist enthusiasts come in!). You’ve probably heard that some other species are able to clone themselves or reproduce asexually (none of that sperm and egg grossness). The Appalachian Gametophyte can undergo this same process with a few special cells called gemmae. These gemmae can’t be dispersed very far, but that hasn’t stopped this fern species from finding cozy places to start a sizable congregation of replicates! The gemmae in question are much larger than the typical spore, so blowing away in the breeze isn’t quite as easy. While it does still happen albeit only short distances, the other two ways of dispersal are via water and potentially by animals. A 1995 article by Kimmerer and Young documents slug dispersal of some bryophytes, so we should all give them (the slugs) a round of applause for doing their part and helping spread the love and the gemmae.
Some more evidence for these limited dispersal capabilities include the species absence in regions north of the last glacial boundary. It’s not that the species can’t survive this far north as transplant studies have shown this to be the case. Hypothetically ideal locations like disturbed roadsides and tunnels within the species range are uncolonized even though in nearby substrates the species will flourish. Because of the geologic history of the area and the plant’s distribution it fits perfectly into the framework that the sporophyte did exist sometime before the last ice age, but afterwards lost the ability to create mature functioning ones. These spores explain the current wide range that the Appalachian Gametophyte occupies, as without them their current form utilizing gemmae only would not be capable of this sized range. It’s very unlikely that today’s populations (like the one we found above) are currently being sustained by long-distance dispersal from some tropical sporophyte source. Allozyme studies (which allow for a multitude of genetic tests) confirm that the DNA makeup of the species isn’t consistent with this theory, as well as the simple fact that the sporophyte hasn’t been observed yet. Combine that with the dispersal range of the current populations and it’s quickly apparent that the dispersal method of these plants is limited by their larger gemmae, thus limiting any significant growth of their range.
Invasive Species
It wouldn’t be a walk through the park (or rather woods) without discussing some of those pesky annoying invasive species, and today I present to you the barberry (Berberis), which can be easily identified by its spine at the base of each leaf. If it’s unwelcoming spines aren’t enough of a reason to dislike this non-native species, it’s also recently been linked to higher tick populations which nobody likes (what with diseases like Lyme’s and Rocky Mountain spotted fever). This pesky plant made its way to North America from European settlers during the 1600s, although it does have a ‘common’ and a ‘Japanese’ variety. In addition to being unfriendly to botanists that touch and friendly to ticks in general, the common barberry can host a deadly fungus that causes black stem rust disease in grain plants. Due to these many reasons, if you see a patch of this species growing you can help the native species by either physically removing them or chemically applying herbicide to the plant itself, but do mind that you don’t accidentally damage surrounding foliage that should be left alone (https://ohioline.osu.edu/factsheet/anr-0106).
Troubled Tree
(photo credits not attributed to me for these nasty adelgids; https://dec.ny.gov/nature/animals-fish-plants/insects-and-other-species/hemlock-woolly-adelgid)
Two for one, we’re looking at the Eastern Hemlock again in this very same blog page! Although this section’s highlight is a little more somber as the Eastern Hemlock is currently under threat by the hemlock wolly adelgid. The aphid-like insect is native to Asia and invasive here in North America. This parasite eats the hard-working tree’s starches, and ultimately can lead to tree death (tree murder?!) over a few years. As we discussed previously the Eastern Hemlock makes great canopy cover that provide numerous other species an ideal habitat to call home which makes the loss of this species a dangerous outcome with many unknown consequences. There are some methods of control and prevention, but anything to rescue/’cure’ an already infected tree is economically inefficient and reserved for special trees (I’ve still yet to figure out exactly what classifies a special tree other than “ornamental and high value’). Thankfully there are some alternative remedies including some predator insect species (Laricobius nigrinus and Sasajiscymnus tsugae are species of beetle and Leucopis argenticollis and Leucopis piniperda are species of silverflies). These biological controls are giving the wolly adelgid a taste of their own medicine and hopefully saving an iconic acidophile in the process. (https://dec.ny.gov/nature/animals-fish-plants/insects-and-other-species/hemlock-woolly-adelgid)
Are you guys out of breath? Because I sure am, but that might be due to the change in altitude hiking out in Hocking County. Either way, I must bid you adieu and farewell until the next adventure! Happy hunting fellow botanists!