Grass: Background Information
Cows of the dairy herd at Hawthorne Valley Farm graze all summer on the
pastures surrounding the vegetable gardens. When they return to the
barn twice a day for milking, they also deposit manure which then gets
collected, composted, and used as fertilizer in the vegetable fields
(here seen behind the cows).
(click image to enlarge)
Our pastures are composed of 30 to 50% grass, mixed with legumes and a variety of other plants, such as dandelions. Our
Photographic Guide to Common Pasture Grasses and Legumes
gives hints how to distinguish our common pasture and lawn grasses,
even if they are not in flower or fruit (please allow the file some
time to upload, it will get there, eventually...).
If you are interested in delving deeper into the world of grasses, we
recommend two excellent little books for starters. The old and tried
First Book of Grasses
by Agnes Chase offers wonderful line drawings (see below), which really
help one understand grass morphology and the often perplexing terms
used in grass identification. The not quite as old but equally tried
Grasses: An Identification Guide
by Lauren Brown is a handy compilation of our most common grasses,
sedges and other grass-like plants, with drawings and text that help
sharpen one's eye to the diversity of grasses. However, if one wishes
to delve deeper, there is no way to avoid the more technical botanical
literature.
Do grasses have flowers?
Well, yes! Although you need to look close in order to find them.
Grasses are wind pollinated, so they don't rely on animal pollinators.
They produce no nectar, now large and colorful flowers, and no
sophisticated parfumes associated with attracting insects or
hummingbirds. Instead, they produce lots and lots of pollen to ride on
the wind and hopefully find another grass flower of the same species to
pollinate...
Grass flowers are typically arranged in inflorescences.
(click image to enlarge)
On the left of this image (this and the following two line drawings are from the
First Book of Grasses),
you see an idealized branch of a typical non-grass "flowering" plant.
On the right, you see the corresponding parts of a typical grass
inflorescence.
Each grass inflorescence is composed of florets.
and finally, whithin each floret one finds a grass flower:
(click image to enlarge)
It is worth taking a magnifying glass and looking closely at a
flowering grass to see if you can distinguish the three yellow stamens
and the two feathery stigmas!
And how exactly do grasses grow???
Grasses have growth tissue (so-called meristem, indicated with red
circles in the picture above) at the very base of the plant, but also
at each node (where leaves emerge along the stalk). They can grow
simultaneously in all these meristematic areas.
When do grasses grow?
That depends: cold season grasses grow best in spring and fall, while warm season grasses grow best in the height of summer.
(click image to enlarge)
Consequently, in spring, you can find clumps of last year's stalks of
native warm season grasses (such as Little Bluestem) surrounded by
fresh growth of introduced cold season grasses (such as Kenntucky
Bluegrass, Orchard Grass, etc.).
In the summer, a clump of Little Bluestem is much less conspicuous.
A number of uncommon native butterflies are closely associated with Little Bluestem.
Every spring, we look for meadows, such as the one pictured below,
which have plenty of Little Bluestem and promise to be habitat for
these rare skippers which only fly for a few weeks in spring.
If you are the steward of a Little Bluestem meadow or know of one in
your neighborhood, we would love to hear about it and include it in our
spring butterfly surveys.
Bibliography
Chase, Agnes. 1937.
First Book of Grasses. The Structure of Grasses Explained for Beginners. Revised Edtition. Silveus, San Antonio, Texas.
Brown, Lauren. 1979.
Grasses. An Identification Guide. Houghton Mifflin Company, Boston.