Waiting for Fruit

On my neighborhood walks I find myself looking down at strategic moments for fallen fruit.  Tracking the seasonal changes in different trees (aka phenology), involves noting the dates of first leafing out, flowering, fruiting, and maturing and falling of fruits and seeds, then coloring of leaves, and finally leaf fall.  When I can, I check on fruit by looking at the trees themselves, but sometimes this doesn't work.  Some of the trees are simply too tall, with too few lower branches to see clearly.  In some cases, trees bear no fruit, which can lead to some frustration while staring aloft with binoculars.  The lack of flowers or fruit in the youngish pignut hickory in the woods would have kept me guessing for a long time, if not for the flowering and fruiting of a larger neighbor with low branches. 

I was embarrassed to miss a lot of these changes in the big white ash in my yard: it leafed out late in the spring, and I waited a long time for it to show flowers, but saw none.  Only later looking on line did I discover that white ash leafs out and flowers simultaneously--the flowers are small, and the tree very tall with no low branches.  Since all I can see from the ground is leaves, I can only assume it flowered and the fruit is maturing; I will watch for the slender, one-winged fruit on the ground in fall.  

 Crown of sixty-odd-foot white ash catches the sun's last rays.  Other photos are close-ups of the crown, most taken on a tripod, at zoom of 3.6X, and uploaded at full resolution.  Can you find any of the fruits?

I've even attempted to get a look at the ash by telescope: here I'm shooting through

the eyepiece of a four-inch reflecting telescope.  Still nothing.

Several kinds of oaks do this to me routinely.  Female oak flowers are in small and and inconspicuous clusters, but fortunately the male are in drooping catkins that are more visible.  On the other hand, an acorn an inch or less across is hard to spot in a fifty-foot tree.  There are enough scarlet oaks that some have low enough branches for me to watch, but red oaks are much scarcer, and I know of only one indisputable black oak on my neighborhood ramblings.  Both white oaks in my back yard are tall: more staring at the ground.

Red oaks I watch.  The last, on the mound, is actually a cluster of several separate trees;

two of these have small branches at eye level, but these branches did not bear flowers.

The only black oak I've seen in the neighborhood has some low branches, but I would have to 

trespass to get a really good look.  One day soon I'll talk to the landowner.

I was delighted to discover, early in the summer after high winds, a fallen twig that proved that a sugar maple I watch was female; I had concluded that all the sugar maples in my neighborhood were male, since I'd seen no keys (double-winged fruits).  Their invisibly sparse fruiting contrasts with the prolific Norway maples, which often bear so heavily that the tree changes color as the keys mature.  So far, the only way I know there are probably still keys up there somewhere is finding one fallen on the ground, the embryos killed by insects.  Confusing things further, it seems that sugar maples are sometimes bisexual.  So there may be more "females" yet, though with few enough keys that they have not yet declared themselves to me.

 

Fallen sugar maple twig.  The keys have an almost square shape,

unlike the nearly straight keys of Norway maples, or the V-shaped keys of red maples.

Aha! must still be some up there somewhere.

 

Most of the fallen keys I've encountered lately have had both embryos eaten by insects, 

but this one seems to have one seed intact.  I wonder if it would grow?

For all these reasons, I spend as much or more time looking at the ground under such trees as looking at the trees themselves.

Take the time to watch a flower become a fruit

It's well worth it.  It will cement in your consciousness the connection between flower and fruit.  And since every flowering plant is a little different, you learn a little more with each one you watch.

 

Flowers have a great variety of forms, but we have to start somewhere!

Image: Amer. Museum of Natural History 

(http://www.amnh.org/learn/biodiversity_counts/ident_help/Parts_Plants/parts_of_flower.htm) 

The fruit--a closed container around the seeds--is what sets flowering plants apart from other plant groups such as conifers, ferns, etc.  The fruit develops from the ovary (containg ovules that will become seeds) at the base of the pistil (female part) of the flower.  Along the way, most other flower parts, such as stamens (male) and petals fall off.  (Some parts may remain: the five little triangles at the end of an apple are the sepals that originally covered the apple flower bud.)

Fruits come in tremendous variety.

The "seeds" (really fruits) of grasses in many cases look much like the flowers, such as the deertongue grass (Panicum clandestinum) in my "prairie garden."

The shape of other fruits can be hard to predict from the flower.  Here is the red maple (Acer rubrum) I watched in the spring.  The first photo is male flowers, the rest are female flowers/fruits of increasing age.

 

 

 

 

 

Often you can see several stages at the same time, in flowers of different ages on the same or neighboring plants. 

Here is common milkweed (Asclepias syriaca) in my "prairie garden."

Plainly only a few flowers in each cluster produce pods; the rest die or their pods are aborted.

In the fall each pod will mature and split open to release hundreds of flat seeds, 

each floating on the wind below a spray of silken fibers.

Sometimes you can see a gradual process so that the end result is predictable.  Pokeweed* is an annual weed that produces dark, juicy berries that begin as tiny, berry-shaped ovaries.  (In flowering plants, the ovary is the base of the pistil--i.e. female flower part--and contains the ovules that will become seeds.  I think botanists borrowed the term by analogy from animal anatomy.)

The ovary shows at the center of the open flower.  It looks like a miniature berry.

Some flowers can be hard to "catch in the act" of becoming fruits, such as dandelion and Queen-Ann's-Lace, which close up and transforms "in secret."

 

Dandelion (Taraxicum officinale) flower at left, closed at right, open once more with mature fruit in center.

Image from http://www.washingtonpost.com/wp-srv/special/metro/urban-jungle/pages/110419.html

 

The flower cluster of Queen Ann's Lace or Wild Carrot (Daucus carota) closes to form

 a "bird's nest," before making the bristly little fruits you can just make out in bottom photo.

Look at a few kinds of flowers in your neighborhood.  Visit them every few days and watch them change!


*Pokeweed, Phytolacca americana, is the only plant I know that is sometimes listed as poisonous, yet appears in old cookbook recipes for "pokeberry pie."