AUTUMN: FALL COLORS AND SEEDLINGS
early November
In Arcata summer isn't very hot, but it is warm and dry
compared to winter, which is cooler and wetter. Warmth in the
summer, wet in the winter. Plants grow best when they have both
warmth and wet, so in Arcata the in between seasons, autumn and
spring are important.
The first rains of autumn come while the soil is still warm,
so some plants grow then. Some seeds sprout and grow a little in fall,
sit and wait through the cold winter, and grow fast in
the spring. These seedlings are taking a chance of being eaten
by snails or by winter sparrows or of being killed by early
frosts, but they get the head start on spring growth.
SEEDLINGS
Look for seedlings in the Arb, including among the mowed
grass. Here you can find cut-leaf geranium (not a native plant),
the youngest with just its 2 "seed leaves" (=cotyledons), the next
older with one true leaf between the cotyledons, the next older with
two true leaves. The meadowfoam in the Coastal Prairie produces lots
of seeds that sprout now too. Grass seeds sprout in the fall.
A seedling grass is a very fine (like a hair) single blade. A
single, stout blade is a new leaf coming up from already
established underground stems or roots. California poppy
seedlings are distinctively gray, even at the very smallest, with
two, slender, forked leaves. Look for them on and around the
Coastal Prairie and Oak Woodland.
When you see the two cotyledons, as in the geranium and
meadowfoam, you know you are looking at a dicot
(=dicotyledon), a plant with its seed in two halves. Grasses, with one slender
new leaf and a seed looking like a rice grain, are monocots
(=monocotyledons).
FALL COLORS
Autumn is the time when deciduous trees and shrubs in our climate drop their leaves.
These species will grow new leaves in
the spring rather than expose their leaves to the winter cold and
winter storms. Before a tree drops its leaves, it removes a lot
of the nutrients from the leaf tissues and stores these in the
trees sap. As the chemistry of the leaves changes, so does their
color, and we get the beautiful fall colors.
Walk through the Arb noticing the trees and shrubs changing
colors and dropping leaves.
The fallen leaves are an important ingredient in building soil.