Nature Ramblers: Ramble Report June 1, 2023

Leader for today's Ramble: Connie Gray

Author of today’s Ramble report: Linda

Link to Don’s Facebook album for this Ramble. All the photos that appear in this report, unless otherwise credited, were taken by Don Hunter. Photos may be enlarged by clicking them with a mouse or tapping on your screen.

Number of Ramblers today: 30

Today's emphasis: Native ferns in the Dunson Native Flora Garden

Ramblers checking out Southern Shield Fern in the Shade Garden

Reading: Connie read a poem, possibly written by Roy Campbell, from “Our Ferns: Their Haunts, Habits and Folklore,” by Willard Nelson Clute, first published in 1901.

If you would see the lady fern
   In all her graceful power,
Go look for her where woodlarks learn
   Love-songs in a summer bower.
   *******************************
Go look for the pimpernel by day,
   For Silene’s flowers by night,
For the first loves to bask in the sunny ray,
   And the last wooes the moon’s soft light;
But day or night the lady fern
   May catch and charm your eye,
When the sun to gold her emeralds turn
   Or the moon lends her silvery dye.
But seek her not in early May
   For a Siblyl, then, she looks,
With wrinkled fronds that seem to say,
   ‘Shut up are my wizard books.’
Then search for her in the summer woods
   Where rills keep moist the ground,
Where foxgloves from their spotted hoods
   Shake pilfering insects round;
Fair are the tufts of meadowsweet
   That haply blossom nigh,
Fair are the whorls of violet
   Prunella shows hard by;
But not by burn, in wood or dale,
   Grows anything so fair
As the plumy crests of emerald pale
   Of the lady fern, when the sunbeams turn
To gold her delicate hair.

Show-and-Tell: Catherine brought a photo of a fawn taken shortly after its birth in her backyard Wednesday morning. She reported that it took 10-15 minutes for the labor and within the hour the fawn was standing and nursing. By late Thursday morning, the fawn and its mother had moved on.

Linda brought a flower from a Silky Camellia shrub growing near the Visitor Center; Barbara put it to lovely use, below.

Announcements/Interesting Things:

Jan Coyne sent this link to an article about "awe walks," "outdoor rambles designed to cultivate a sense of amazement.” She commented: “What we see on rambles may fall more into the category of “awwww” than awe, but I think we end up often enough in the latter. Nature Rambling: it’s good for you!”

Another link provided by Jan is a real eye-opener about the value of mosses.

Today’s Route: We left the arbor next to the Children’s Garden and walked down the sidewalk path through the Shade Garden, heading to the Dunson Native Flora Garden for the fern walk.

Four ferns planted in the Shade Garden are not native to the Georgia Piedmont: a close but unnamed look-alike of Mariana Maiden Fern, Autumn Fern, and Southern Shield Fern.

A native of east Asia, Autumn Fern, frond (left) and sori (right), is spreading rapidly throughout the southeast. Two short pieces, here and here, tell the story of this species’ journey from ornamental darling to invasive pest plant in just a few years.

Japanese Painted Fern is native to eastern Asia and, so far, is well behaved, i.e. it has not yet been reported to invade natural areas.

Southern Shield Fern is native to the southeastern Coastal Plain but has begun to spread aggressively throughout north Georgia as it has become a favorite in the nursery trade.

Ferns have two different growth patterns – clumps and patches – which are determined by the position of their rhizomes (underground stems). If the rhizome is erect, the fronds emerge from its tip in a clump, usually forming a vase- or fountain-like tuft of fronds. If the rhizome creeps along horizontally underground, the fronds will emerge from buds scattered along its length, forming a more or less scattered patch of fronds. Examples of clump-formers include Christmas Fern, Southern Lady Fern, and Cinnamon Fern. Patch-formers include New York Fern, Netted Chain Fern, and Sensitive Fern.

Clump of Christmas Fern (left) and patch of Netted Chain Fern (right)

One thing that makes ferns seem difficult to learn is the vocabulary that is unique to this group of plants. As most people do know, fern leaves are usually called fronds. Less well known is the term for the leaflets that make up the frond: a pinna is one leaflet, pinnae is the plural. The margins of a pinna may be shallowly scalloped or deeply lobed, but if the pinna is fully divided to the stalk, separated from adjacent pinnae, it is a subleaflet called a pinnule. These may even be subdivided further into pinnulules or -lets, but let’s stop there! It is the repeated division of the fern frond that people mean when they describe a plant as looking “ferny.”

Christmas Fern fronds are divided into pinnae that are shaped like Christmas stockings.

Royal Fern fronds are divided into pinnae (red outline) that are divided into pinnules (yellow outline).

Ferns reproduce by spores, not seeds. Spores are dust-like reproductive structures produced in sori (single: sorus). The sori are usually round or crescent-shaped and found on the lower surface of the fronds. But in many species sori may be found elsewhere such as the tips of fronds or in special, separate, fertile fronds.

Ebony Spleenwort's crescent-shaped sori are held on the lower surface of pinnae (left). Sensitive Fern's bead-like sori are produced on separate fronds (right).

Southern Lady Fern is a clump-forming fern found in moist forests throughout the southeast. Lower elevation plants have reddish stalks; mountain plants (above 3,500 feet or so) have green stalks. Both have been planted in the Dunson Garden..

Our first stop in the Dunson Garden was the Southern Lady Fern. On many fronds, the bottom pair of pinnae point downward from the stem “like little lady’s slippers.” Unlike many other ferns, Southern Lady Fern has hairless stalks because, you know, southern ladies shave their legs. (Some ramblers disagreed with this generalization.) This species is distinguished by the shape of its pinnae – they are about the same width for most of their length then abruptly taper to a point, a shape known to botanists as “acuminate.” The lobes of Southern Lady pinnae have finely toothed edges.

Southern Lady Fern pinnae abruptly taper to a point.

Southern Lady spores are produced in crescent-shaped sori on the undersides of the pinnae.

Christmas Fern is one of the most common ferns in Georgia, growing in a wide range of habitats from dry upland woods to streamside bottomlands. It can be identified by its evergreen fronds and pinnae shaped somewhat like Christmas stockings. Its leaf stalk is green with tan scales. Last year’s fronds will remain around the base of the plant till they disintegrate in late spring.

Christmas Fern's sori are clustered on pinnae at the tip of the frond.

Ebony Spleenwort, another common fern, looks like a small version of Christmas Fern except its leaf stalk is dark in color – glossy brown or black – and wiry. Ebony Spleenwortwill grow in poor, dry-ish acidic soils that most other ferns won't touch.

Ebony Spleenwort sori are crescent-shaped and located on the lower surface of pinnae.

Royal Fern occurs in sunny marshes and shady, wet areas along streams. Both its pinnae and pinnules are widely and regularly spaced. Spores are produced in tan, tassel-like clusters at the tips of the fronds (below).

Rattlesnake Fern has only one large, triangular sterile leaf per plant; it is held more or less horizontally at the top of the fern's stalk and is divided into several pairs of lacy, much divided pinnae. In mid-spring, a second and very different leaf rises from the same point at the top of the stalk – it is slender, tan, erect, and bears many round sori.

Sterile leaf of Rattlesnake Fern

Rattlesnake Fern with erect fertile leaf (left); close-up of sori on fertile leaf (right)

Georgia has two species of maidenhair ferns: Northern Maidenhair Fern and Southern Maidenhair Fern, occurring respectively in north and south Georgia (mostly). In both species, the pinnae are delicate and fan-shaped, with the sporangia tucked under small flaps of tissue along the edges of some pinnae. Both species grow only where soil moisture and pH are high.

Northern Maidenhair Fern has a broadly fan-shaped or semi-circular frond, with the soft, blue-green pinnae radiating out from the top of the black, wiry, erect stalk.

Southern Maidenhair Fern grows among the rocks lining the wash. In the wild, it is most often found growing on damp limestone. Its stems are black and glossy and the blade is typically drooping and oval in outline with many pale green pinnae.

Sensitive Fern frond

We stopped next at the Sensitive Fern patch beneath the double-trunked Tulip Tree. Individual fronds arise from an extensive network of underground rhizomes that form large patches. The fronds of Sensitive Fern are not fully divided into pinnae – they are, instead, deeply lobed with wings of tissue along the midvein connecting the lobes. The edges of the lobes are wavy or scalloped. Sensitive Fern grows in moist to very wet sites. Its name reflects its sensitivity to cold.

Sensitive Fern frond eaten by insects

A number of the fronds have been eaten by insects, unusual for a fern. The larvae of the sawfly Hemitaxonus dubitatus is known to eat Sensitive Fern leaves but this insect has not been documented in Georgia. Dale pointed out that sawflies aren't really flies -- they're Hymenopterans, related to wasps, bees, and ants.

Sensitive Fern spores are produced in separate fertile fronds that look nothing like the sterile fronds. Brown, bead-like sori are held on branches clustered at the top of an erect stalk and will open to release thousands of tiny spores. Fertile fronds are produced in the summer; today, we saw several fertile fronds from 2022 that had dried and persisted through the winter.

Netted Chain Fern is a near look-alike to Sensitive Fern and occupies the same wet habitats.

Netted Chain Fern is named for the chain-like pattern of small veins that line the midvein of every lobe. These are best seen on the lower leaf surface. Sensitive Fern lacks these chain-like veinlets.

Netted Chain Fern has a separate fertile frond as does Sensitive Fern. But Netted Chain Fern holds its sori in narrow chain-like links.

New York Fern is easily identified because the fronds are widest in the middle, narrowing at both ends, because...“New Yorkers burn their candles at both ends.” In the wild, this species forms large patches, often blanketing entire hillsides. Only one insect is known to feed on its fronds, the caterpillar of Pink-Shaded Fern Moth (Callopistria mollissima), a widespread species in the eastern U.S.

Broad Beech Ferns are a patch-forming fern with fronds scattered along widely creeping rhizomes. Its two lowest pinnae angle downward, creating the characteristic "fox-face."

Goldie's Wood Fern occurs in high-elevation boulderfields and nutrient-rich cove forests over mafic bedrock in north Georgia.

Marginal Wood Fern is a clump-forming fern found mostly in the mountains. It's considered evergreen because its fronds overwinter, spreading flat against the ground to maximize the amount of sunlight they can capture on short winter days. The overwintered fronds are pretty beat up by spring and disintegrate as new fronds begin to emerge.

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Marginal Wood Fern is named for the location of the sori which typically line the margins of the lobes of the pinnae.

The Cinnamon Fern population in Dunson is much diminished from past years, with only a few fronds so far this year.

Cinnamon Fern fronds are easily identified by the small patches of white or tan hairs at the base of the pinnae, aka “hairy armpits.”

Flowering plants and fungi are making the transition to summer in the Dunson Garden.

Fairy Finger fungi growing among the ferns.

Smooth Phlox draped with a Hog Peanut Vine, with a Daddy Longlegs in the center of the flower.

Black Cohosh is still going strong in Dunson.

Richard Eaton sent this message last week:

“While I was standing by the flowering Black Cohosh last Thursday, there wasn’t much discussion of the smell of the flowers, only that they didn’t smell very good. Someone near me said that she thought that they smelled like mothballs. That was interesting to me since I had spent a few years studying the bacterial metabolism of the usual component of mothballs, naphthalene.* So I took a sniff. The flowers did indeed have a mothball odor. However, it is more likely that the chemical causing the smell is indole which, when concentrated, smells similar to naphthalene and thus mothballs. Indole is best known as a product made by the bacterium, E. coli, which gives it the characteristic fecal odor. E. coli make indole from the amino acid, tryptophan, using the enzyme, tryptophanase. Possibly black cohosh has a similar ability.”

Further research on this topic brought Richard to this article, “Roses are Red, Violets are Blue, White Florals Smell Like Feces.”

*Eaton, R. W. and P. J. Chapman.1992. Bacterial metabolism of naphthalene: construction and use of recombinant bacteria to study ring cleavage of 1,2-dihydroxynaphthalene and subsequent reactions. Journal of Bacteriology 174:7542-7554. Link to this article.

SUMMARY OF OBSERVED SPECIES

Unnamed look-alike of Mariana Maiden Fern, Macrothelypteris torresiana

Rice Paper Plant Tetrapanax papyrifer

Southern Shield Fern Thelypteris kunthii

Autumn Fern Dryopteris erythrosora

Arborvitae "Fern" (a spikemoss) Selaginella braunii

Japanese Painted Fern Athyrium niponicum

Southern Lady Fern Athyrium asplenioides

Christmas Fern Polystichum acrostichoides

Royal Fern Osmunda regalis

Rattlesnake Fern Botrypus (Botrychium) virginianum

Southern Maidenhair Fern Adiantum capillus-veneris

Sensitive Fern Onoclea sensibilis

Netted Chain Fern Woodwardia areolata

New York Fern Thelypteris noveboracensis

Northern Maidenhair Fern Adiantum pedatum

Broad Beech Fern Phegopteris hexagonoptera

Fairy Fingers fungi Clavaria fragilis

Goldie’s Wood Fern Dryopteris goldieana

Cinnamon Fern Osmundastrum (Osmunda) cinnamomea

Marginal Wood Fern Dryopteris marginalis

Smooth Phlox Phlox glaberrima

Ground Nut Apios americana

Daddy Longlegs Family Opiliones

Black Cohosh Actaea racemosa

Thursday, June 1, 2023

Ramble Report June 1, 2023