Introduction

Some of the most fascinating families of plants are the ones that have evolved their way to terrestrial life, paving the way for the vast diversity often taken for granted in terms of surviving in what was then a foreign environment.  Bryophytes include mosses, liverworts, and hornworts; nonvascular plants lacking seeds, still requiring a moist environment to reproduce. In contrast, this page will also cover the perplexing lichen, a symbiotic relationship between fungi and cyanobacteria or algae that exist as some of the most resilient and abundant organisms across a variety of surfaces on every continent. For this field trip, our class visited Duranceau Park near Hilliard, Ohio, alongside the Scioto River. This area is rich in limestone, existing on the glaciated western portion of the state. Braving a slight sprinkle and some mud, we were able to find a great number of vascular, nonvascular, and not even plants!


What Are Lichens?

Lichens often end up looked over, especially in consideration of the towering broadleaf trees or colorful sprays of wildflowers, yet, these organisms harbor not only beauty, but a fascinating ecological role and intricate anatomy. These organisms are the symbiotic relationship (in which both individuals benefit) between a fungus and usually algae but occasionally cyanobacteria. The majority of lichens belong to the group of fungus Ascomycetes that posses cup like spore producing apothecium. Lichens are so unique in that they do not resemble either of the members of their relationship, producing new chemicals neither can produce and living where neither can live alone. This family consists of the earliest form of succession in areas where no soil or suitable substrate is present, growing on rocks and other impervious surfaces. They allow for areas to later be colonized by plants. This versatile lifestyle makes them abundant and widely distributed, second only to bacteria.

Anatomy

 

The anatomy of lichens are particularly interesting due to the existence of two organisms intertwined. Within lichens, fungi act as the farmers of the products of photosynthesis conducted by algae or cyanobacteria, where the nutrient absorbing hyphae of the fungus wraps around algal cells. The structure of the organism itself comes from the tightly packed hyphae. For instance, the anatomy of a foliose lichen is depicted to the right. The outer surfaces present in the upper and lower cortexes are made of compressed cells, while the area between them is composed of loose hyphae from the fungus. Between the hyphal medulla and upper cortex lies the algal cells where photosynthesis takes place. Rhizines anchor a lichen to the surface they grow upon, with a variety of complexities from simple to branched. Lichens can also reproduce sexually through spores or asexually through a form of fragmentation.

 

 

Morphology

Lichens occur in three distinct forms: crustose, foliose, and fruticose. Crustose lichens are similar to a thin crust on the surface they grow on, tightly adhered and often in a circular pattern. Their upper cortex is hard and dense, followed by a thin algal layer and medulla that is directly on the substrate. Crustose lichens lack a lower cortex or rhizines making it near impossible to remove them whole from the substrate.

Foliose lichens posses leafy growth from the outer margin consisting of lobed leaf like structures. The anatomy of these lichens is described above with the upper and lower cortexes, algal layer, loose medulla, and rhizomes. Foliose lichens can be attached flat against a substrate or curled away at the edges.

Finally, fruticose lichens appear as tiny branches and leaves or hanging vines. They are usually long and thin while being round or flat in their branching sections. Unlike foliose lichens, fruticose lichens lack a definite top and bottom and can even have a hollow center. A family of fruticose lichens named cladoniform posses a crustose thallus and an upright fruiting structure called a podetium. Unfortunately, we were unable to locate a fruticose lichen on our field trip, so this page will only feature crustose and foliose lichens.

A foliose lichen growing on a fallen branch

Ecology

Throughout evolutionary and historical time, lichens have played a large role in many niches and human uses. Animals have relied on these organisms for food, shelter, and camouflage particularly common in arthropods. Birds often utilize lichen to forage in, such as the White Breasted Nuthatch or Black-and-white warbler, while others will use the symbiote to construct nests as does the Northern Parula warbler. Ruby-throated hummingbirds will use lichen as a protective and camouflaged outer coating to their nests. Many amphibians, reptiles, and arthropods have evolved crypsis camouflage to blend in with lichen covered rocks or bark. Some species are reliant on a particular type of lichen, such as the Reindeer Lichen present from Ohio up into the Arctic circle. During the long winters in the Arctic, this lichen is the primary food source for Reindeer of which the ecosystem and native peoples rely on.

In terms of human uses, native groups have utilized lichens for dyes, decoration, and even food in troubled times. Certain poisonous lichens were used to tip weapons used for hunting. Some varieties are anti-bacterial and are used medicinally or for products such as deodorant.

https://www.fs.fed.us/wildflowers/beauty/lichens/didyouknow.shtml#:~:text=Other%20lichens%2C%20like%20Usnea%2C%20are,salves%2C%20extracts%2C%20and%20perfumes.

 


Lichen Field Identifications

While at Duranceau park, we were able to spot a variety of incredible lichen species. Here are the IDs and information about a few!

Common Button Lichen

Buellia stillingiana

Note the black apothecia

This crustose lichen is tightly adhered to the rock

This species of lichen is crustose, living on the surface of rocks and trees in light shade and occasionally on other lichens to which it adhered strongly. The vegetative tissue or thallus is a pale gray sometimes sporting cracks. The apothecia are always present and are black, circular dots resembling buttons. This species is very common in the Eastern US. This individual was found on what was likely decorative limestone rocks placed along the road entering the park.

 

 

 

 

 

 

Rough Speckled Shield Lichen

Punctelia rudecta

This lichen was surrounded by individuals of its kind and sunburst lichen

Rough Speckled Shield lichen is a fairly large, brightly colored foliose lichen that typically grows on trees in light shade but is also found on rocks. The center of the thallium has dense clusters of isidia for asexual propagation. The body itself is a dusty greenish teal with broad, rounded lobes and a brown undersurface that can peel up from the substrate. The tips of the lobes have white spots known as psuedocyphellae where hyphae from the medulla break through the cortex. This species is relatively common and found in every county in Ohio. It has been used as a dye that creates a magenta color.

Almost the entire trunk of this buckeye was coated in lichen

Hooded Sunburst Lichen

Xanthomendoza fallax

The sunburst lichen coats the limestone fence next to a Bloodroot plant

Another incredible looking foliose lichen, this one with a mustard yellow adorning its crowded and narrow lobes. The Hooded Sunburst Lichen is small and usually combines individuals on non-acidic bark or alkaline rock in full sun such as limestone as the individual we found was on. The asexual powdery buds of soredia burst from the slits on the edges of the thallus. This lichen is more likely to be spotted in the limey glaciated western Ohio.

 

 

 

 

 

 

 

 

 

 

 

Common Stippleback Lichen

Dermatocarpon muhlenbergii

This lichen was found on dry rock surrounded by patches of moss

The Common Stippleback Lichen is a foliose lichen that grows to be about an inch in diameter rooted at a single point. The thallus is round, leathery, and varying shades of gray that can become a dull green when wet. The underside is brown while the surface is littered with raised dark brown dots that are the mouths of sexual, spore producing perithecia. Once spores are released, they must pair with the correct algae species to form a stippleback. This lichen grows on dry alkaline rock in full shade, as this specimen was found on dry limestone in a small ravine. The species is found across the US.

 


Bryophyte Spotlight

Bryophytes are a group of non-vascular plants that evolved to survive on land, but are seedless, still requiring water in order to reproduce with flagellated sperm. Moisture is required for their survival as they are unable to transport nutrients through the phloem or xylem that makes up vascular bundles in other land plant lineages. They instead absorb nutrients through the air and on their surface, lacking roots to extract from the substrate. These plants are unique in that they consist of primarily gametophyte, making up the visible green leafy portion one associates the plant with. Bryophytes produce spores in structures that grow out of the gametophyte, often tall thin stalks with a capsule that produces the spores. The bryophytes include mosses, liverworts, and hornworts, two of which will be featured on this page!

Porella Liverwort

Porella navicularis

This liverwort was tucked away in large patches of moss on the rock

This liverwort was a great find, tucked away in a rocky, moss covered ravine that was freshly wet from rain. When young, these liverworts form thick mats, but as they age they jut out from the rocks or trees they are rooted on. They are usually 2-3 times pinnate. The margins are toothed and ovule to ovate in shape. They are a dull green-yellow color and can be identified chemically turning violet when exposed to iodine potassium-iodide.

https://fieldguide.mt.gov/%5C/speciesDetail.aspx?elcode=NBHEP2Q0H0

Obtuse-Leaf Tortula Moss

Tortula obtusifolia

Note the orange stalks of sporangia

The intricate foliage and bright sporangia of this moss jut out from the base of a limestone rock on the side of the road at Duranceau park. When moist, the leaves of this moss open up into angular tufts that are oblong to ovate-lanceolate. Through a microscope, the leaf cells are square and covered with papillae and differentiated base cells. Individual plants are autoicous posessing both male and female structures. It prefers calcium rich substrates and is found throughout the middle of Ohio.

(https://ohiomosslichen.org/moss-tortula-obtusifolia/


A Note on Chinquapin Oak

Chinquapin Oak (Quercus muehlenbergii) is a notable tree, preferential to the limey substrate of glaciated western Ohio where this individual was found. They very closely resemble Chestnut Oak but differ slightly with thinner leaves posessing 8-13 pairs of sharp lobes and gray, flaky bark. It is a species of white oak as noted by the lack of bristle tipped leaves. Chestnut Oak typically prefers the acidic soil seen in eastern Ohio, making it easier to differentiate the two based on location.

Flaky bark. The acorns mature in one season and are sweet

Simple, alternate, oval to elliptical shaped leaves

 

 

 

 

 

 

 

 

 

 

 

 

 


Other Trip Highlights

A family of geese along the Scioto River

Plitt’s Rock Shield Lichen (Xanthoparmelia plittii)

Lemon Lichen (Candelaria concolor) amongst moss and other lichens

Bottlebrush Frost Lichen (Physconia leucoleiptes) alongside sunburst lichen

The small ravine we found the liverwort and common stippleback lichen within

A carpet of Claopodium crispifolium moss

Anomodon moss (Anomodon attenuatus)

Moss covered limestone

Tufts of mosss

Bark blanketed in barebottom sunburst lichen (Xanthomendoza weberi)

A closer look at the sunburst lichen

A view up the ravine

Blue Ash (Fraxinus quadrangulata)

Note the opposite pinnate leaves

Canada Moonseed (Menispermum canadense) a highly poisonous vine

Woodland Stonecrop (Sedum ternatum) displaying succulence

Twinleaf (Jeffersonia diphylla)

The capsule fruit of Twinleaf, the flower usually blooms for only a day

The calciphile Hackberry (Celtis occidentalis)

Black Haw (Viburnum prunifolium) berries

Bladdernut (Staphylea trifolia) with opposite trifoliate leaves and a capsule nut

Norway Maple (Acer platanoides)

Eastern Redbud (Cercis canadensis) with grapevine

Pink galls most likely caused by insects on a Red Elm (Ulmus rubra)

European Buckthorn (Rhamnus cathartica)

A field of Mayapples (Podophyllum peltatum)

False Solomon’s Seal (Maianthemum racemosum) in bloom

Blooming Largeleaf Waterleaf (Hydrophyllum macrophyllum)

 


References

Information on the trees and woody shrubs was sourced from Peterson’s Guide to Trees and Shrubs (1986) by George A. Petrides. Identification and information on lichens was found in the Common Lichens of Ohio Field Guide (2015, OH DOW) by Ray Showman. All other sources have been cited, but we can’t forget the vast amount that Dr. Klips contributes in the field.