These two relaxed days of searching for tiny treasures not only yield some great photos, but provide ample opportunities for expanding knowledge too. And as a special bonus, such quiet pursuits also serve to refresh the spirit. A lifetime puttering through these mountains daily would never lack stimulating interests for the mind or soothing balm for the soul.
Dr. Ken McFarland and his wife Linda drive up Sunday afternoon to walk Injun Creek and examine mosses. Ken leads hikes on this trail during the Spring Wildflower Pilgrimage demonstrating the finer points (pun intended) of several of the common mosses in the park. There are also liverworts and even one hornwort on the trail as well. Under his tutelage, I closely view these tiny plants through a hand lens and take notes with the intent to photograph them in the following days.
Mosses, liverworts, and hornworts are collectively referred to as bryophytes. They do not possess water-transporting tissues in the same manner as other plants and are considered “non-vascular.” Absorbing needed water through leaf tissue, a moist habitat is often critical to the survival and reproduction of many of these species. Sometimes just a single cell layer thick, they can change color and curl in dry conditions, but at the first touch of moisture, they green up, unfurl, and are ready to resume vital processes such as photosynthesis.
Droughty summers aside, the Smokies provide an ideal habitat for these plants. Mossy logs, rocks, and trailsides abound here thanks to high annual rainfall and plenty of seeps, springs, and streams. There are a few distinguishing characteristics of mosses. Typical moss leaves have a midrib, taper to a single point, and are arranged spirally around the stem. Leafy liverwort leaves lack a midrib, are either rounded or lobed with two or more points, and align in two distinct rows along the stem. Liverworts can also produce thin, flat tissue called a thallus rather than a leafy stem. Hornworts are similar in appearance to a thallus liverwort, but with the aid of a hand lens a single chloroplast is visible in each cell.
Two genera of mosses, Hypnum and Thuidium, are often called “log mosses” as they can be found carpeting old downed trees. Thuidium, the fern moss, is decompound –the leaves branch multiple times to give it a delicate, feathery look. Thuidium delicatulum is by far the most common of the three species found in the Southern Appalachians.
Robust clumps of Atrichum moss are commonly found in moist shady areas. The spirally arranged leaves splay out from erect stems in a starry fashion. The darker midrib is easily detectable with wavy-edged translucent leaf tissue to either side.
Mnium has broad, nearly transparent leaves with tiny teeth and a midrib that projects into a point at the leaf tip. Some shoots lie flat, others stand erect in little rosettes. Rhodobryum roseum is a distinctive moss that also grows in rosettes.
A species found on rock, soil, and tree bases throughout Eastern North America is Bryoandersonia illecebra. Ken describes the drooping, round leafy shoots as cat tails, which give populations a shaggy look. The long, tapering leaf tips are transparent with a spiral twist. It is quite common, almost weedy.
Leafy liverworts can be found on tree bark and downed logs as well as streams and seeps. The green growth that first colonizes a decorticated (without bark) log is usually a leafy liverwort, Norwellia. From a distance it looks to be a smooth, solid coating like algae, but close inspection reveals fine strands with tiny curved, double pointed leaves. Mosses arrive later in the next successional wave of life on the log.
Another really cool leafy liverwort is Trichocolea tomentella. It is pale green and many-branched with something of a puffed, fuzzy look thanks to leaves that are made up of numerous tiny, hair-like filaments. It is found close to streams.
There are two easily recognizable, large thallus liverworts in the park. In streams and other wet areas look for Conocephalum salebrosum with its scaly looking polygonal pattern. There will often be large patches of it. Dumortiera hirsuta has a dark green, smooth thallus and in spring produces slightly elevated, hairy discs to protect the sporophytes.
While photographing the liverworts, I notice a small white spider on a nearby leaf. She is camera shy at first, trotting from one side of the leaf to the other as I attempt to take her picture. She finally relents. It is a White Micrathena (Micrathena mitrata) related to the gray, big-butt Spiny Micrathena Mary and I kept running into on Old Settlers. It has two small projections on its back. Along the Plemmons Cemetery trail, I find a few of the gray, big-butt spiders and several of these smaller White Micrathena with their webs stretched between the shrubs.