Sex in the Grass

I was poking though old posts recently, spotted a minor typo in this one, thought, "what the heck," and corrected it.  That's when I made an important discovery: Blogger moved the post to the current date (from late June 2014 when originally posted), so that it went to the top of the blog.  Now I've learned my lesson, but will add this preamble and bump it once more, now that grasses are again coming into glorious flower

Okay: really "sex among the grasses" would have been more accurate--but would it have gotten your attention?

The grasses in my neighborhood are all hot-to-trot right about now, and that gives me the chance to talk about a pet peeve: the way people use the term "flower."  

A great many people are unaware of most flowering plants because they only notice flowers that are large and showy.  But showiness is just that: a bid to attract attention.  --just not ours.  

Showy flowers are in the business of attracting pollinators, to overcome one of the key disadvantages of the rooted life: an inability to go out dating.  For any sexual reproduction, sperm from the male must get to the egg of the female.  For most animals this is not a problem: they can move.  For plants it is a biggie.

Most plants overcome this problem by enclosing their sperm in a pollen grain, and then having some way to get this pollen grain from the male part (stamen) a longish distance to the female part (pistil) of the flower on another plant.  Most flowering plants do this with the help of animals recruited for the purpose.  These animal "chaperones"* are informed  of a plant's randy status with colors or odors, and  bribed with nectar or the like to be the go-between.  In a typically mutually beneficial arrangement, the animal (whether bee, bat, bird, etc) gets a reward for delivering the pollen to the receptive stigma of a flower on another plant, and then Baby is on the way.  Of course, it's helpful if you and your Honey are in the mood at the same time: hence flowering seasons.    More people should blush at the sight of blatant sex all around them.

Of course, the contented beetles are a good clue, but

how else can you tell that the swamp dogwood above is insect-pollinated, 

but the pignut hickory below is not?

Not all plants use animals as go-betweens.  Some prefer to let their love waft on the wind.  Among these are conifers, of course; the sperm-bearing pollen that pines coat all surfaces with at this time of year is the detritus of a veritable orgy.  But some flowering plants are also wind-pollinated: familiar oaks and maples release pollen from small, inconspicuous flowers with tiny, dull-colored petals because they have no need to attract animals.  One downside of this habit--at least for many of us--is seasonal allergies.  

 A few wind-pollinated trees: Norway maple, scarlet oak, and paper birch.

 

 The grasses go these trees one better: they don't even have petals.  For grasses, in particular, wind pollination makes sense: grasses typically live in in dense stands in which likely sexual partners are close by, so a little breeze is all that's required to complete the tryst. 

A few grasses from my neighborhood.

*In an old and jocular sense, and rather the opposite of what their parents intended.

Spring 4a

Five of the trees I follow have been changing all through June.

Black Oak with acorns begun last season and maturing this season (on woody twig), and tiny new acorns in their first year (on green twig).  (Both second and first years occur in the 1st & 3rd photos.)

River birch with expanding leaves and maturing fruits on May 30th, maturing leaves and fruits on June 5th, and shedding and shed, winged seeds on June 16th (3), and the "spikes" remaining after seed drop. plus a portrait, on the 19th (2).

White pine with male cones nearly ready on May 23, and just beginning to shed pollen on the 30th. Spent male cones and young female cones (hanging from branches right of middle) on June 5th (2); and shed male cones and growing female cones on the 16th (3).

 

The sugar maple on the corner still had its rather meager stock of samaras on June 13th.  By the 16th (2) many had fallen.  Fewer were visible on the 19th (3) and 22nd (2).

 

 Basswood finally flowers.  Flowers beginning to open on the 13th, huge bud mortality shown by fallen bracts, but remaining flowers in full bloom on the 16th (3), and 19th (3).  Finally, on the 22nd, two trees nearer to home finally began to bloom (2).

 

 

Mark the solstice--literally

I've given up--for now, at least--the idea of making a shadow calendar that would mark the passage of the seasons as a shadow moves from one solar noon to the next.  But simply marking solstices or  equinoxes is simplicity itself.  Try it yourself, tomorrow!

Theoretically, you could find the position of the sun at solar noon on any particular day, choose an object to cast the shadow, and measure the angle to see where that shadow would fall.  But it's far, far easier to simply wait for the event in question, find a convenient shadow, and mark where it falls.  

You could do such a mark at sunrise, sunset, or solar noon.  Sunsets and sunrises change direction as the seasons pass (really!*), while solar noon marks the greatest height the sun reaches on a given day.  (All three of these things also vary in time.)  Since trees and buildings block our view of sunrises and sunsets around here, solar noon makes the best target, and it's what I marked. 

Your first job is to find out the time of solar noon tomorrow--the day of the summer solstice.  Go to NOAA's solar calculator.  Enter enter your latitude and longitude, OR) move the nearest orange pin on the map to your location.  I like to put the pin right on my house, but for practical purposes that's overkill: a few miles either way won't matter.  (The sun moves [okay, the earth turns] one degree of longitude every four minutes.  At my latitude of 42 degrees north, a degree of longitude is forty-five or so miles.)  Change the date to June 21.  Click the box for daylight savings time, then click Save.  You now know the times of sunrise and sunset, and the time of solar noon.  (Other check boxes will make lines on the map showing directions of sunrise and set, and the current position of the sun.)  WRITE DOWN THE TIME OF SOLAR NOON.  

As I write, the NOAA solar calculator page keeps timing out--probably swamped with interest so close to the solstice.  Keep trying!

Notice that, not only is it not at noon, it's also not at one o'clock, as you'd expect with daylight savings time.  Here, solar noon comes at 12:45pm, EDT right now.  Part of the reason is that time zones are about fifteen degrees of longitude (one hour of time) wide.  Only those in the east-west center of the time zone could reasonably expect noon to be on the hour.  (Since we in eastern Massachusetts are east of the center of the eastern time zone, solar noon always falls before clock noon.)  The rest of the difference is more subtle, and also causes the time of solar noon to vary by a minute or more from day to day, and tens of minutes from season to season. 

On Sunday go outdoors half-an-hour or so before the time of solar noon.  You need to scope out a good shadow.  The shadow ought best be pointed, and should be cast by a something permanent at some distance away (say, ten or twenty feet away).  I used a corner of the roof, whose gutter casts an angled shadow.  As the sun continues to move westward, that shadow will move eastward, so you need to make sure it will still fall in a convenient place at solar noon.  (In the event it doesn't, you may want to find a back-up shadow.)  

Marked yesterday, when it was sunny.  (Two days before the solstice is close enough

in my book.)  The shadow of the roof corner will just cover this rock tomorrow.

Added 6/22: A cloud blocked the sun right at solar noon on 6/22, but a minute 

later the shadow appeared.  In that minute, the shadow had already advanced

an inch to the right.  (The roof casting the shadow is about 20 feet away.)

That's pretty much it.  Just figure out how you can mark the location of this shadow when solar noon arrives.  This shadow falls on the ground right now, which I marked by pushing a little stone into the ground at the point of the shadow with my foot.  At the equinoxes, on the other hand, that shadow falls on the side of the house, and I marked it in indelible marker.  

Henceforward, every summer solstice (usually about June 21st) that shadow will appear in exactly the same place.  If you're lucky enough that that same shadow will fall on the same surface at the equinoxes and winter solstice (a very tall order), you will be able to mark those the same way.  Then you could watch the sun's noontime progress between those marks, as the earth makes its stately, tilted way around the sun season year after year.  

This was a few days after the fall equinox.  (The shadow has passed, 

since solar noon was ten or fifteen minutes before.

To summarize:
1. Enter your location in the NOAA solar calculator site (not forgetting daylight savings) and find the time of solar noon for June 21.
2. Go out safely before solar noon on the 21st and find a convenient shadow.
3. At solar noon, mark the location of that shadow. If it's cloudy, do it tomorrow!  (Close enough!)


* You can see from the figure below that the sun rises and sets south of east and west in the fall and winter, but north of east and west in the spring and summer.  Curiously, the paths of the sun across the sky are always parallel to each other.  The figure is approximately correct for mid-northern latitudes like those here in New England.