Public Is Invited

Spring 2012 Newsletter

Thursday, April 12, 7:00 PMSelby Hall, Rm 150,

Marietta CollegePresenter: Dr. Ed Michael

Dr. Michael, of WV University, will describeand discuss the life history of the turkey

vulture, a common bird of Ohio and much ofNorth America. His talk will include

identification of the turkey and black vulture,anatomy and reproduction, seasonal

movements, and a video illustrating feeding ofthis fascinating bird. (See note on page 2

about Dr. Michael’s latest book).

Thursday, May 10, 7:00 PMSelby Hall, Rm 150,

Marietta CollegePresenter: Tom O’Grady

Tom will be presenting recentinvestigations of Ohio’s extensivemound building showing that, like

ancient construction that has occurredaround the world, alignment of thesestructures may correspond with rising

and setting points of

celestial bodies.

Vultures-

Thursday, June 14, 6:30 PM Meet at the Hermann Fine Arts Center parking lot, 4th & Butler Leader: Brad Bond A trip to the Ohio River Islands National Wildlife Refuge Head- quarters in Williamstown. We’ll see what's in bloom as we look up-land and down below near the river. Milkweed will be in bloom with its fascinating entourage of aphids, caterpillars, butterflies and beetles. And we expect to see a lot of other fauna and foliage.

The Sun, Moon and Stars – Guidepostsfor Ancient Builders

Beauty inthe Eye of the Beholder

Along the Riparian Way

Marietta Natural History Society

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Page 2 Marietta Natural History Society Spring 2012

Suggestions, Comments orContributions for the MNHS

Newsletter?Send them to the Editor:

374-8778 spilatrs@marietta.edu

Dinner with the speakers

We will meet at 5:30 at the Levee House RestaurantCheck first with Marilyn (373-3372) or Elsa (373-5285). to be sure speaker will be there. Members should make their own reservations.

Marietta City Bird WalksCommune with nature to start your

Tuesdays, from 6:30 to7:30 AM Leader: Lynn Barnhart

April 17 at Kroger Wetlandmeet in Acme Street parking lotApril 24 at KrisMar Woods

meet in parking area on Hillcrest behind Tractor Supply

May 1 at Oak Grove Cemeterymeet at Wooster St. entranceMay 8 at Kroger Wetland

meet in Acme Street parking lotWear comfortable shoes and dress for the

weather. Binoculars would be useful but are not necessary.

DEATH VISITS CANAAN

. . . is the name Dr. Michael's latest book and he willhave some available for purchase by MNHSmembers on April 12.

In Death Visits Canaan we learn about the author'sdiscovery of a solitary gravestone in Canaan Valley. This rough, hand-carved stone shows the date ofdeath, December 5, 1880: making this the oldestdated object in Canaan Valley. Through exensiveresearch, Dr. Michael discovered the identity of thisnine-year old and the basic details of his family'sill-fated adventure in the Canaan wilderness. Thebest part of Dr. Michael's novel may be hisdescriptions of the mountains, forests, and wildlifeawaiting those families who ventured into the greatCanaan wilderness that existed as late as 1890.

Earth Day Celebration Saturday, April 21, 10 AM - 2 PM

Marietta Armory SquareThere will be hands-on activities, interactive displays,

environmental exhibits, green technologies (solar panels,wind turbines, hybrid cars), informational booths by localcolleges and environmental groups, recreational games

for children, and much more. Two contests will be held: aTrash-to-Art contest (anything goes!) and a Sweetgum

Tree Ball contest (create a decorative or practical way touse the multitude of sweetgum balls in the area.) Bring

your contest entries to Earth Day. Prizes will be awarded.Come join in this free fun for all!

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Recycled Paper 30% Post-Consumer

Venus Transit Visible this Spring On June 5 Venus canbe observed to cross the faceof the Sun – a Venus Transit.Only 3 such transits have occurred in the last 200 years (1874, 1882 and 2004), and the next transit to offer agood viewing opportunity will be in 2025. The transit path and local transit times are shown inthe diagram. Interior egress will begin at 6:20 PM, and thetransit will have progressed to about the midpoint ataround sunset. The initially straight chord, representingVenus' trajectory, is transformed to a curved path due to the rotation of the earth on its axis. For lots more information and resources check out . The site includes history, educational resources, links to regional viewing ‘events’, and guides for safe-viewing. You can purchase inexpensive solar shades through the web site.

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THE WONDER OF POLLEN by Paul Knoop -Naturalist and Environmental Educator

Living prior to the invention of the microscope wouldhave been frustrating. It is hard to imagine a time whenpeople were not aware of the presence or significance ofbacteria, viruses, fungus spores or plant and animalreproductive cells such as pollen and egg cells. Becausethese small living objects could not be seen, all sorts ofstrange ideas were conjured up to explain causes ofsickness, the origin of new plants and animals, orthe magical appearance of fungi. Today wehave the means to examine these smallparticles and determine just what part theyplay in the grand drama of life on theplanet. One drama being played out during thisearly spring season is the pollination offlowering plants. For plants to successfullyreproduce the male part of the plant (pollen) mustcome into contact with the female part of the plant (ovule).Consider the problem here. The female pistil (which leadsto the ovule) is pinhead size and must be hit by amicroscopic grain of pollen at exactly the right time. The

distance the pollen must travel may be afraction of an inch or miles. Moreover, theright kind of pollen grain must hit the rightkind of target. No other will do.

The sheer wonder of this process iseven heightened when one considersthat it is accomplished by incidentalagents. In our part of the world mostpollination is carried out by either

insects or wind. Insects, while collectingpollen and/or nectar for food inadvertently transfer pollengrains to pistils. The wind is indiscriminate and scattersuntold billions of pollen grains around the landscape. Thelaw of averages dictate that each little pin-head sized pistil,waiting for a particular type of pollen, will be hit. The wasteseems staggering and yet flowering plants cover thelandscape in infinite variety. The pollination by insects and wind also insurescross-pollination. In any living organism it is essential thatgenetic material be mixed throughout the population. Inplants, as in animals, this genetic material is housed instrange little microscopic ribbons of matter calledchromosomes. Some sets of chromosomes, complete with

all the characteristics of the plant, arelocked in the ovules. Other complete

sets are locked in the pollen grains.When arriving at the pistil thepollen grain will "germinate" andgrow a long tube which travelsdown the inside of the pistil to theovule. The result is a new plant

(seed) with all the characteristicsof two separate parent plants.

Looked at under a microscope,

pollen grains are exquisitelybeautiful. One botanist talksabout "pollen jewelry" as thesesmall bits of protoplasm take onthe shape of microscopic golfballs, footballs, canoes, helmets,dumbbells and sunbursts.

The outside cover of pollen - its sculpturedarmor - is practically indestructible and is often

preserved in peat bogs. One central Ohiopeat deposit 30 feet deep and 30,000 yearsold shows different kinds of pollen atdifferent levels. During a period 4,000 years

ago, this deposit shows a predominance ofprairie vegetation in Ohio. Evidently the

climate in eastern North America became drier,causing the eastern forests to recede.

Pollen is a curse to many people because it causes hayfever. Perhaps the most insidious pollen is that producedby the ragweed plant. This plant, which thrives inhuman-altered environments, has airborne pollen that isextremely irritating to the mucous membrane of eyes, noseand throat. When its pollen is being released in August andSeptember, the invisible pollen dust is found in every cubicyard of air over the ragweed belt. Yes, pollen can be troublesome to humans at times, butremember that life without it would be impossible. Our livesand the lives of all other animals depend upon thereproduction of plants, and pollen is a critical link in thatprocess.

Pollen Q and AWhat is the internalanatomy of a pollengrain? A pollen grain has arelatively simple structure,yet, from an evolutionarystandpoint, it is an entire plantreduced in size and complexity to twocells. The pollen grain contains two walls, and twocopies of the genetic information. One copy of theDNA is in the nucleus of the pollen grain cell, theother is present in a ‘generative cell’ -- actually a cell-within-a-cell, since the generative cell resides withinthe cytoplasm of the surrounding pollen grain. When the pollen grain germinates, a long tubegrows through which the nucleus andgenerative cell travel to the egg.

See Pollen Q & A, page 5

Page 5 Marietta Natural History Society Spring 2012

2011 Pollen Count (grains/m3) Summary fromDayton/Montgomery County Regional Air Pollution ControlAgency http://www.rapca.org/air_quality/pollen_mold.htm

Cont. From page 4

What happens during pollination? Pollination refers to the deposition of pollen (male) onthe female reproductive structure of flower, called the pistil. When a pollen grain lands on the pistil of a suitable flower,it produces a long tube that grows down the pistil’s

elongated ‘style’ toward the bulb-like ‘ovary’ atits base. Within the ovary reside the femaleeggs (called ovules), and fertilization occurswhen the pollen tube reaches the ovules.Following fertilization in a typical flower, theovary gives rise to the fruit and the ovules toseeds.

In flowering plants ‘double fertilization’occurs! The pollen tube delivers twocopies of the male plant’s geneticmaterial (each held in a structure called anucleus) to the ovule. One fertilizationprocess gives rise to the embryo of the

new plant, the other creates the foodstorage tissue of the seed called

endosperm. The ovary of a flower may contain a single ovule,which upon fertilization yields a single seed (suchas the single large seed of an avocado). If theflower contains many ovules, a fruit will beproduced containing many seeds (for example anorange, bell pepper, and cucumber)

What is the record holder for the longestpollen tube? Let’s ‘ear it for corn. The ‘silk’ of corn isactually the elongated style of a female pistil.After emerging the style elongates about 1 - 1½inches per day. Corn pollen need not land onthe tip of the silk for pollination to occur,nevertheless, the pollen tube may need togrow several inches to reach the ovule. Eachtassel (containing the male flowers)produces millions of pollen grains, and atypical corn ear (containing the female flowers)produces 750 - 1000 ovules. Although self-pollination does not usually occur, pollenproduction exceeds ovules by several thousand-fold.Inevitably many pollen grains will land on a style, but onlyone will eventually fertilize the ovule. In a large ear ofmodern hybrid corn, under good conditions as many as400 to 600 ovules will mature into kernels.

Why do pollen grains have such elaborately shapedouter walls? Some examples of pollen grain shapes are shown onpage 4; from top to bottom: dandelion, lily, pine, andamaranth. Pollen grains are so diverse in theirappearance that they have long been used as a tool forplant identification and taxonomic classification. Scientistsin the field of palynology can use pollen grains in soil and

lake sediments todetermine the types ofplants growing in an areain the past; and forforensic palynology, pollengrain analysis can yieldcritical evidence from acrime scene. But why dopollen grains have suchbeautifully patterned andsculpted surfaces? The answer may not beobvious or universal, leading to disagreement amongexperts. The most straightforward answer would be thatsurface features of pollen grains have evolved to enhancetheir transport to other flowers. For example, pollen grainsof some wind-transported conifers have extensions calledsacci that outwardly appear to aid in wind transport, butmay actually be a flotation device. Some studies havereported correlations between surface features andpollination by beetles, flies, bees, moths, or birds. Butthere is scant hard evidence showing how a particularsurface feature is coupled to a specific type of pollinator.

Why does pollen cause allergies? Certain broadleaf plants (“weeds”), grassesand trees produce pollen associated withallergies. Ragweed, curly dock, lambs quarters,

pigweed, plantain, sheep sorrel are some of the mostprolific broadleaf producers of pollen allergens. Generally, wind-pollinated species are the culprits

behind most types of pollen allergies. Allergies arise when a person’s immunesystem reacts abnormally to certain protein

constituents of pollen grains, acting as if theywere a pathogen of some sort.

The table below shows the annual ‘seasons’ for high levels of pollens from the different groupsas recorded in the Dayton area.

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The MNHS Missioni To foster awareness of and sensitivity to our environment and its biodiversityi To provide a place where people with these interests can gather for information and activityi To create a presence in our community representing these ideas

Marietta Natural History Society P.O. Box 983 Marietta, Ohio 45750 (740) 373-5285