Ramble Report July 7 2016

Today's Ramble was lead by Dale Hoyt.

All the photos in this post are compliments of Rosemary Woodel, except where noted.

Today's post was written by Dale Hoyt.

Twenty-two Ramblers met on a cool summer morning.

Today's reading:  

Dale read an excerpt from Edwin Way Teale's Circle of the Seasons entitled The Measure of an Enthusiasm. (Teale was probably the most popular nature writer in the mid-twentieth century (before Rachel Carson). He won a Pulitzer Prize for his travel book, North With the Spring, as well as the John Burroughs medal for distinguished nature writing.)

The measure of an enthusiasm must be taken between interesting events. It is between bites that the lukewarm angler loses heart. It is between birds that the mildly interested watcher gives up. The true devotee possesses an enthusiasm that burns so fiercely it carries him over the uneventful between times when nothing is happening.

Rambler leaving: Today was Molly Longstreth's last Ramble with us. She is moving to Arkansas. If you would like to stay in touch with her she can be contacted at this address.

Today's route: We took the mulched path down to the Dunson Native Flora Garden; slowly walked through the DNFG and returned to the parking lot via the road and the cement walkway.

Dunson Native Flora Garden: Our focus today was on the ferns in the DNFG, but we also took note of other plants and animals.

Fern structures

Linda gave us a quick overview of the terminology used to describe fern structures. Here's a brief summary:

stipe	the part of the stem from the ground to the first "leaves"
blade	the part of the frond that is "leafy"
frond	the entire stipe and blade
rachis	the part of the stem within the blade
pinna (pl.: pinnae)	a "leaflet" attached to the rachis
pinnule	a subdivision of a pinna
pinnate	the blade is divided into a number of pinnae, each attached to the rachis at a single point
pinnatifid	the pinnae are broadly attached to the rachis
sporangium (pl.: sporangia)	a microscopic structure that produces spores
sorus (pl.: sori)	a collection of sporangia, often brown, but may be black, green or yellow, depending on spore color

Beech buds

Developing buds of American Beech

In the fall the American Beech tree has uniquely shaped buds found at twig tips and leaf bases. They are long, cigar shaped and have sharply pointed ends. These buds are now beginning to form. At present they are only about 1/16 inch long, but already have the pointed tip. When mature they will be approximately 1/4 to 1/2 inch in length.

Spores and Seeds

Ferns and mosses can reproduce two ways: asexually and sexually. Sexual reproduction produces spores, which are the dispersal phase of the fern or moss life cycle. In this way spores are like the seeds of flowering plants – they enable the plant's offspring to find suitable habitats a long distance from the parent plant. But there the similarity ends; spores are on their own whereas seeds have been provided with a head start in life. Each seed contains an embryonic plant in a state of suspended animation. The seed also contains a food supply to help the young plant get established before it can start an independent life. Spores have none of these. They are single cells and when they germinate they must immediately begin to make their own food supply through photosynthesis. The seed has the luxury of that pre-packaged food supply. It's embryo can sink a root into the soil using that food source as its energy supply. The shoot part of the embryo can wait until the root is established before it starts to grow and make more food for itself and its root. Spores and seeds represent two different reproductive strategies: either 1) produce a small number of offspring, each endowed with a packet of food, or, 2) produce an enormous number of propagules, none of which have anything to tide them over or help them get established. A flowering plant may produce hundreds or thousands of seeds, but a fern produces millions or billions of spores.

"Fern balls"

Some Ramblers spotted a ball-shaped structure at the end of a Christmas fern frond. It appeared as though the terminal third of the frond was rolled up, forming a roughly spherical ball. This is not the first time a Rambler group has seen this. Two years ago Ramblers saw several of them, both here in the SBGG and elsewhere. The story of what makes these curious structures is told here.

Fern herbivory

Whenever you look at a fern you should be impressed with what you don't see. You almost never see signs of it being fed upon. This immunity from attack by herbivorous insects is due to the presence of toxic chemicals in fern tissues. In ferns as well as many other plants these substances are a major defense against being eaten. But they are expensive to make so plants often don't produce them until they are needed. This makes the fresh leaf susceptible to attack. In the case of the Fern ball caterpillar they feed on their first ball for a while and then leave, seeking out another frond where they construct a second ball and commence feeding again. It is not known for certain, but it could be that the fern tissue becoming more distasteful as a result of the caterpillar feeding, requiring it to move to a new host plant.

Seed dispersal by ants

Seeds inside this trillium seed capsule are dispersed by ants

Many of the plants that flower early in the spring produce seeds that are adapted to dispersal by ants. Each seed has an energy-rich "handle," called an elaiosome, that ants avidly seek out (see Linda's book, p. 44, for a photo of Trillium elaiosomes). The foraging ant carries the seed back to its nest where the elaiosome is stripped off and fed to other members of the nest, the queen and the developing larvae. The seed is then discarded, either carried out of the nest and dropped with the bodies of dead ants and waste material or placed inside the nest in special latrine areas. In either case the seed has a rich environment in which to germinate and grow. Additionally, many seeds must have the elaiosome removed in order to germinate. In this way such plants can slowly spread over the landscape, one ant hill at a time.

We saw two plants today that depend on ants for their seed dispersal: the Large Flowered Heartleaf, a type of wild ginger, and a Trillium with a developing fruit that has not opened yet. The Heartleaf was surrounded by a large number of young plants. Perhaps it was located very close to an ant nest and its seeds didn't get carried very far.

Fruits

Jack-in-the-pulpit with developing fruits, each with a single seed

Painted buckeye fruits

Mayapple fruit

Goldenseal ripe fruits

Fruits are the packages that contain the seeds of flowering plants. There is great variation in the packaging as well as in the number of seeds in the package. In some plants the fruit consists only of the pistil and its contained seed or seeds. In others there are additional parts derived from other tissues of the flower. Today we saw the developing or mature fruits of several plants that flowered earlier this spring: Jack-in-the-pulpit, Painted buckeye, Mayapple, Trillium and Goldenseal.

Jack in the Pulpit

We saw several Jack-in-the-Pulpit plants with developing fruits today. The story of how these plants can change sex, switching from male to female and back, can be found here. Each small green sphere is the fruit of a single flower and contains one seed. The fruit will develop an intense red color when ripe. which attracts birds.

Goldenseal

The fruits were abundant on June 9 this year, but today we only saw one plant with its bright red berries. Like the Jack-in-the-pulpit, the red berries appeal to birds that digest the pulp and later pass the seed.

Painted Buckeye

You may remember earlier this spring that many of the shrubby buckeyes in the DNFG bore racemes of yellowish-green flowers. Now some of those flowers have produced fruit, but many of the plants have none. George wanted to know why. Not all the buckeyes produced flowers this year. Trees and shrubs often don't flower when they are young and even the shrubs that arise as root suckers won't flower until they have aged a few years. Other factors affect the amount of fruit set. When pollinators are not abundant or are ineffective in pollen transfer fruit set is limited. There could be only a few flowers with functional pistils, as in the case of Bottlebrush buckeye. I haven't been able to find any information about the Painted buckeye to indicate if they are similar to the Bottlebrush in being limited by the number of complete or perfect flowers (Complete or perfect flowers have both stamens and pistils.) To answer this question we'll need to carefully examine the flowers when they bloom next spring.

The fruit contains a single seed within a relatively thin shell. Squirrels (and, perhaps, Chipmunks) eat buckeyes, but for other mammals (humans, livestock) they are poisonous.

Trillium

The Trillium seed pod or capsule will split open when ripe, liberating its contained seeds with their elaiosomes. (See the discussion of Ants and seeds, above, and also see Linda's book, p. 44, for a photo of Trillium elaiosomes). Trilliums are just one of many plants with ant-dispersed seeds.

Mayapple

The Mayapple fruit is the only part of the plant that is edible and then only when ripe. The ripe fruit is pale greenish-white. It is consumed by Box turtles without harm and they are probably the major dispersal agent for the seeds. One of the compounds derived from the plant, podophylline, has been used in cancer chemotherapy.

Hibiscus flowers

Hibiscus flower; stamens with dark anthers surround the style;
5 branched stigmas project forward on end of style.

There are two Hibiscus currently flowering in the DNFG, H. moscheutos and H. coccinea. These plants exhibit the characteristic flower structure of the Mallow family – the long, projecting pistil and the stamens that completely surround the pistil style nearly up to the end where the stigmas are. The nectar glands of the flower are at the base of the petals. This seems like an unlikely arrangement to assist in pollination because small insects that come to feed on the nectar would not come in contact with the stigmas very often. But these flowers can easily be pollinated by humming birds whose heads would contact the anthers and stigma while they imbibe nectar. Also, surprisingly, a recent study showed that small bees transmitted pollen to the stigmas, but mostly when they tumbled around while fighting each other. Bees that entered the flower alone were ineffective as pollinators. Video of bee visiting a Hibiscus flower. (Watch the first 15-20 seconds; you will see a bee fly into the blossom, bumping into the stigma. It spends the rest of the video nectaring and then gathering pollen from the anthers.)

Other blooming flowers at the bottom of the DNFG that were attractive to pollinators are Scarlet bee balm and Smooth Coneflower. The Rattlesnake master is not yet blooming, but we saw it blooming two weeks ago in another part of the garden and it was covered with bees and wasps.

Ferns

I confess I had difficulty identifying the ferns from their photographs, so I'm going to include only those that I am confident of. All the ferns we looked at today are in the List of Observed Species at the bottom of this post.

Christmas fern fertile frond (undersurface); sterile fronds in background

Broad Beech fern; 2 basal pinnae point in a different direction

Sensitive fern

Scouring Rush

Scouring rushes are planted near the deer fence at the bottom of the Dunson Garden. We saw them as we walked up the road on our way back to the Arbor. The common name refers to its use by early travelers to scrub out pans after cooking. The plant has a high silica content that makes it good for scrubbing out dirty objects. Another common name for the genus Equisetum is "Horsetail" and refers to the appearance of the other species. They have a ring of thread-like leaves arising from each joint of the stem, making the entire plant resemble a horse's tail. But the Scouring rush lacks these leaves and doesn't resemble a horsetail in any way, shape or form. In the recent past horsetails were thought to be an evolutionary lineage independent of ferns, but more recent DNA sequence analysis suggests that they really should be included with the ferns.

Passion Vine

Climbing up the fence near the Scouring Rush was a Purple Passion-flower, unfortunately not in bloom. (The flowers only open for a single day.) It had two fruits the size of large eggs and many people think these are the origin of another common name for this plant: Maypop, because if a child stomps on the fruit it may pop. It turns out that this is an example of "folk etymology." The real origin of the name, was revealed in Who Named the Daisy? Who Named the Rose?, by Mary Durant, 1976, Dodd, Mead & Co., NY.

. . . often known by the charming nickname of maypop, but not because it blooms in May. Maypop is the anglicization of the Indian maracock, as the Virginian tribes called it, the name having made its way from the Tupi Indians of South America, up through the Arawak and Carib tribes, and into North America. In the original Tupi, the name was maraca-cui-iba -- the "rattle fruit" – because of the gourd-like fruits whose seeds rattle when the fruit is dried.

The "passion" part of the name does not refer to any aphrodisiac property. It is a reference to the passion of Christ. Early Jesuit missionaries to Brazil in their efforts to convert the native people to Christianity made up symbolic biblical references for the flower parts; e.g., the ten sepals and petals represented the 10 faithful disciples, the three styles the three nails, etc.

The juice of a commercial species of passion flower, Passiflora edulis, is widely used as a flavoring in beverages and ice cream in Latin America. Avis also reports that passion flower tea is an anxiety-reducer.

Syrphid fly – Yellowjacket queen mimic

Hover fly wasp mimic

Not everyone was around when we encountered a fly that mimics a Yellowjacket wasp. Unfortunately, it flew away and Rosemary was only able to get a quick snapshot when it rested briefly on a wind-blown leaf.

Sulphur shelf fungus

Sulphur shelf fungus

This fungus is also known as "Chicken of the woods."  The common name refers to its edibility. It also is a wood-decaying fungus, rotting the wood of its host tree and ultimately weakening it. I'm uncertain about which species of Sulphur shelf this is. The Mushroom Expert website lists two similar species that infect oaks: Laetiporus sulphureus and L. cincinnatus. The fruiting body of the first is typically seen high up in the tree, the second rots the roots and is seen at the base of the tree, so this one could be L. cincinnatus.

List of Observed Species

Common Name	Scientific Name
Flowering plants
American Beech	Fagus grandifolia
Large-Flowered Heart leaf	Hexastylis shuttleworthii
Jack in the Pulpit with fruit	Arisaema triphyllum
Painted Buckeye with fruits	Aesculus sylvatica
Goldenseal	Hydrastis canadensis
Trillium	Trillium sp.
May apple	Podophyllum peltatum
Rose Mallow	Hibiscus moscheutos
Scarlet Rose Mallow	Hibiscus coccineus
Scarlet Bee Balm	Monarda didyma
Rattlesnake master	Eryngium yuccafolia
Smooth Purple Coneflower	Echinacea laevigata
Purple Passion-flower	Passiflora incarnata
Ferns
Wood fern	Thelypteris sp.
Christmas fern	Polystichum acrostichoides
Southern Maidenhair fern	Adiantum capillus-veneris
Ebony Spleenwort	Asplenium platyneuron
New York fern	Parathelypteris noveboracensis
Northern Maidenhair fern	Adiantum pedatum
Goldie's wood fern	Dryopteris goldiana
Cinnamon fern	Osmundastrum cinnamomea
Netted Chain fern	Lorinseria areolata
Broad Beech fern	Phegopteris hexagonoptera
Royal fern	Osmunda spectabilis (= O. regalis)
Scouring Rush	Equisetum hyemale
Animals
Syrphid fly	Diptera: Syrphidae
Fungi
Sulfur shelf fungus	Laetiporus sulphureus or L. cincinnatus