I'm trying to learn a bit about lichens. Goal: be able to name the very common ones on sight, and gain sufficient facility to run an unknown through the keys. It's great fun and is going quite well, thanks mainly to gracious assistance provided by uber-friendly lichenologist members of OMLA, the Ohio Moss and Lichen Association. If you have an interest in lichens, join the club!

A well-known distinction, and the starting point for lichen identification, is the overall growth form, of which there are three main types: fruticose, foliose, and crustose  (i.e.,  shrubby, leafy, and crusty).

FRUTICOSE lichens are stalked, pendant, or shrubby, with no clearly distinguishable upper and lower surface. The quintessential fruticose lichens in Ohio belong to the genus Cladonia. Most Cladonia species begin development as a scaly (squamulose) primary thallus. ("Thallus" is the general term for a relatively featureless body, the kind had by a fungus, algae, or even some plants, wherein specialized intricate organs are lacking.) Later on, a hollow upright structure, the "podetium" develops. Podetia, depending upon the species, may be pointed, clubbed, or topped by cups and, depending on the species, may bear spore-producting apothecia.

Here are two cladonias seen recently. The first is "peg lichen," C. polycarpoides. This species has fairly long primary squamules that persist after the podetia have formed. Each podetium ends in a large brown apothecium. Peg lichen is common on soil in old fields and roadside banks.


Wand lichen, Cladonia rei, is a cup-forming fruticose lichen that produces apothecia at the tips of numerous proliferations of the cup margins, resembling a little star, giving the overall impression of a magic wand. The primary squamules (not visible in the photo below because it focuses on the upper parts) are small and sparse.


FOLIOSE lichens have a more or less "leafy" growth form, distinctly dorsiventral, and varying in the degree of attachement to the substrate, from completely adnate to only centrally attached (umbilicate). Foliose lichens seem to be especially common on tree trunks, comprising most of the ones on this hardwood at Dawes Arboretum in Licking County, Ohio.


CRUSTOSE lichens are in contact with the substratum at all points and lack a lower tissue layer (the cortex) had by the other lichen types. Crustose lichens cannot be removed intact without removing a portion of the substrate as well. Here's the very unremoved substrate of a couple of crustose lichens noted recently at the OSU-Marion campus.

Nearby, a community of mosses and liverworts occupies a decorticated log.


Nearby, an American sycamore proclaims "Trespassing Violators will be Ted." That doesn't make any sense. Who's Ted?

Snow trillium (Trillium nivale, Liliaceae, the lily family) is our smallest, earliest, and cutest trillium.

A couple of small annual weeds are exceedingly common and abundant in disturbed open ground, including agricultural land adjacent to Terradise Nature preserve in Marion, Ohio. They're flowering now. How is that possible? Don't flowering plants need time to grow from seed? Yes, they do. And the way these plants accomplish the feat is by being "winter annuals." The seeds of these winter annuals germinate in fall or winter, grow during autumn and also during winter warm spells, remaining dormant but alive when it's really frigid. Come spring, and "ta-da!!," flowers, then fruits, releasing seeds that wait until cool weather to sprout, avoiding summer drought (the adverse season).

 

Excepting oddities like skunk cabbage and various flowering trees that are oblivious to pollinators (e.g., silver maple, see below), our earliest wildflower is one aptly dubbed "harbinger of spring," Erigenia bulbosa (Apiaceae, the carrot family). The species may be fairly frequent in our deciduous forests, but is easily overlooked because it protudes only a mini-bit above the leafy ground.