In the onrushing course of evolution, as flowering plants
gained a majority presence on land, the grassy clan adapted to nearly every
niche. With their growth point located near or below ground level - rather than
at the stem tip - they could more successfully recover from grazing, trampling,
fire, drought, and climate severities.
Three grassy plant families now present at Halibut Point are
closely enough related to be grouped together as Graminoids: the true grasses Poaceae,
the sedges Cyperaceae, and the rushes
Juncaceae.
If the plant before you has long narrow leaves with parallel
veins, very likely it's a Graminoid. If its stems are circular and hollow with
nodes swollen where leaves join the stems, think true grass-
Poaceae. If the stems are edgy and
probably triangular in cross section, think sedge-
Cyperaceae. If the stems are circular, solid, often wiry-looking,
with leaves that usually sheath the stems, think rush-
Juncaceae.
|
Calmagrostis canadensis, Canada blue joint |
Across the moister areas of the Halibut Point heath at this
moment a tall grass Canada blue joint is blooming with a cereal-looking
inflorescence.
|
Calmagrostis canadensis closeup |
It shows the kinds of features that have made grasses an
inseparable part of human civilization, the backbone of agriculture and
livestock pasturage. Wheat, corn, rice, all the cereal grains have their
origins as grasses. The
Poaceae sugar
cane and bamboo also make extensive contributions to mankind's economic life.
|
Danthonia spicata, Poverty grass |
Many grasses adapt to dry conditions by approaching dormancy
in hot weather, even to the extent of shedding their leaves once the flower
stalk is launched. A considerable portion of a grass plant's succulence is
stored protectively within the root system. People commonly prod their lawns into
mid-summer growth only by watering them regularly through the heat.
|
Setaria faberi, Chinese foxtail |
|
Setaria viridis, Green
foxtail |
There are upwards of thirty species of grasses to be found
at Halibut Point. Getting oriented to the distinctions can be daunting. A
friendly guide opens doors.
|
Chris Leahy reverses
his binoculars for a close look. |
When we took a tour together, ornithologist-field botanist
Chris Leahy demonstrated a resourceful way to magnify the details of a grass
flower.
Chris reads the flora along with other landscape features as
one picture. Scanning the plants at eye level he predicts terrain, soil
qualities and moisture. Looking down at ground characteristics he predicts
specific plants. Along with knowing 'jizz' - the general visual impression of
various plants - as well as the cycle of their seasonal development, and
pertinent historical factors, he is well prepared to name the Graminoids we
encounter without using identification keys. He narrates an ecological story.
|
Schizachyrium scoparium, Little bluestem |
Little bluestem is one of the native grasses that Chris
champions as a crucial constituent of the 'leaner'
habitats on Halibut Point. It tolerates hot, dry
soils with little fertility. It is the exclusive host (that is, food) for the
caterpillar stage of some species of butterflies.
|
A wet area with a
localized ecosystem |
Quarrying operations left scattered pits that have
naturalized into damp fens where we find Canada rush (
Juncus canadensis) Toad rush (
Juncus
bufonius),
Three-square sedge (Scirpus
americana), and Wool sedge (Scirpus cyperinus).
|
Juncus tenuis, Path rush |
|
Path rush seeds
developing |
Juncus tenuis seems
exceptional among local
Juncaceae in
its ability to adjust to both damp and dry areas. Tough and wiry it tolerates
foot traffic and contributes to the groundcover in compacted walkways throughout
Halibut Point, earning the name 'path rush.'
|
Juncus effusus, Soft rush |
The more statuesque
Juncus
effusus is a fiber of choice source for weaving baskets and mats, resulting
in the common name 'soft rush.'
|
Soft rush seeds
developing |
Circular stems, miniature lily-like flowers, and
nutty-looking seeds give rush plants a characteristic look.
|
Carex crinita, Fringed sedge |
Cyperaceae family
members like this Fringed sedge tend to have clumps of flat-leaved arching
foliage with 'edgy' flower stems that are triangular in cross-section.
|
Cyperus pseudovegetus, Marsh flatsedge |
Most of the
Cyperaceae
grow in wet areas where their architectural forms stand pleasingly above the
water surface.
|
Scirpus microcarpus, Barber-pole bulrush |
One of the more ornate
Cyperaceae,
Barber-pole bulrush, distinguishes itself with a colorful stem pattern.
|
Barber-pole bulrush in a water-retentive pocket |
It has established itself in a particularly fortunate
location for Halibut Point State Park visitors.