Leaves that Close at Night, by Amy

It all started when I went out to look at a special wild tree, called a Palo Verde tree, near our home.  It was about two weeks ago, and I went in the late afternoon.  Usually the leaves on this little tree look like this: wide open, tiny leaves that reach to the sunlight.

Palo Verde leaves in sunlight

But on that afternoon, they looked like this: folded up against each other.

Palo Verde leaves in shade

 They were in the shade, as the sun was beginning to set; and I remembered that I had seen them half-closed on another day when I visited in the afternoon.  You can see it again in this picture.

Palo Verde leaves in shade

It was a fascinating question: do leaves close at night?  Do they close in the shade?

I asked some friends on my garden blog, and the answer was "Yes!"  Some leaves close at night, just as some flowers close at night.  Botanists call this "nyctinasty".  (Botanists are the scientists that study plants.)  They don't know yet what advantage it gives for the plant.

Although no one seems to know why it happens, botanists do know how it happens.  At the base of the leaves there are miniscule cell structures that contain extra water.  As this water is pumped in and out of the cells, the leaves open or fold.  The cells act as little hinges.

It is most common in plants from the pea and bean family, called the Legume family.  This is actually a very large group which includes many plants we don't think of as peas or beans!  Here in the desert there are several very fine plants that are Legumes.  The wild Palo Verde tree is a Legume.  So is my beautiful young Fairy Duster shrub.  Its leaves also close in the shade and at night, like this...

Fairy Duster leaves in afternoon shade

Fairy Duster leaves in afternoon shade

I wondered whether plants from northern climates close their leaves as well.  I learned that they do.  Even some garden beans close their leaves at night.

I went out to look at my young sweet pea plants.  Although I am growing them in my desert garden, they are originally from cooler climates, so I thought I would like to see what they were doing in the evening.

Sure enough, some of their leaves were folded!  But I am not sure yet whether these are folded for night, or just because they are young!

Sweet pea leaves in afternoon shade

The Sparrow Flies South

Under the porch a Sparrow sits.

The Sparrow Flies South

North, up in the northlands, the year is growing old.

The sweet white snow is falling, and the wicked ice and cold.

Out in frosty hay-fields, the hay sits wound in bales.

Overhead the wide-winged goose, last in phalanx, sails.

Now geese are plump and water-tight, and do not fear the chill.

But under the porch a sparrow sits, fluffed out and feeling ill.

"What shall I do?  The leaves are brown that once were green and light,

And all the sun has seeped away that kept us warm and bright.

"All morning-time, I've found three seeds that rattled in the winds;

The rest are deep beneath the snow, or eaten by my friends."

A little sunbeam slid its way, down cloud, down roof, down porch;

It sat upon the chilly step and flickered like a torch.

"Oh listen, Little Bird!" it cried, and danced, and waved, and shone.

"It is not time to linger here, all fretful and alone.

Down South, down west, in Southlands, the sun is still aglow;

The earth is warm for sparrow-feet, there is no icy snow.

"In gardens by warm wall-sides, a thousand seed-heads nod,

And newly planted crop-fields hold seeds beneath the sod.

And other small brown bird-wings go flicking up and down,

While tuneful voices singing, go winging through the town."

The little sparrow perked his head, and through his fluff and cold

Sat hearing all the sunbeam said, the stories that he told.

"You say," he asked, "there is a place this frightful winter storm

Finds just too far to wander, where it is bright and warm?"

The sunbeam waved and nodded.  For a moment even he

Was just too cold to speak, though he wanted to agree.

The tiny bird sat thinking, and then at last he said,

"I know which way is southward; and West, the sun is red."

He took the sunbeam on his wing; it quivered, still alight,

Upon his feathers as he flew; he kept it on his right.

Beneath his left wing, though it chilled, he took an eastward gust,

A tiny breeze that wished to reach the desert and the dust.

All day, all night, all day he flapped, with tired wings he flew,

Until earth changed from white to tan and sky from gray to blue.

"This is the desert," said the beam, "this is my favorite spot

Where other sunbeams dance all day, and make it clear and hot."

The little bird looked down and saw the cracked and barren ground.

He didn't see a single tree or stem of grass around.

"This is my favorite place to blow!"  The gust of wind laughed loud;

He dropped to play with grains of sand, and made a dusty cloud.

"Keep flying west!  Keep flying west!" the sunbeam urged the bird;

And then the ray danced upward, assured the sparrow heard.

Do you know who's in your garden at the very glimpse of dawn?

It is the little sparrow - see his feathers brown and fawn.

See him dance among the seed-heads; he is no more fluffed and cold,

He is full of song and merriment, he is plump and brown and bold.

He has promised very soberly to only glean the weeds.

But sometimes he can make mistakes, and eats the garden seeds.

Still, think how happy he must be to find among the leaves

There's still a flower blooming - or to dangle from the eaves!

He patters on the tile and he chirps along the straw,

And he shakes the brittle seed-pods with an eager, tiny claw.

If you ask him how he came here, as he hops along the walk,

He will say a sunbeam told him.  But just how do sunbeams talk?

As he hops along the walk...

Poetry and Pictures made for Ian, Karina and Lewis by Sarah