macro-elements or
macro-nutrients |
- there are certain mineral elements that are essential
for plant growth. Some of these
nutrients are needed in
relatively large amounts for plant growth and these are
called the macro-elements or macro-nutrients.
Others called
micro-nutrients, are required in relatively small
amounts but both groups are essential for proper,
healthy plant growth.
The most common macro-elements
include those usually found in a bag of
fertilizer;
nitrogen (N),
phosphorus
(P), and potassium (K).
Other macro macro-nutrients
include
calcium,
magnesium and
sulfur which are found in
adequate amounts in most soils. They occasionally need
to be supplemented but only if shown by the results of a
soil
test. |
maculata |
- Latin term for middle. The
term aureomaculata would mean a gold colored in the middle of
the leaf. |
male flower |
- the male part of the flower is called the
stamen which consists of an anther and
filament. The
pollen is produced on the anther.
See Female Flower |
marginal
variegation |
- variegation that occurs on the outer edge i.e. the
margin, of a leaf.
See
medial variegation and
splashed or
streaked variegation in hostas. |
mature |
- 1) Plants that have reached the stage
of development where they are capable of
sexual reproduction
i.e. flowering and setting seed.
- 2) Also, a mature plant or clump is one
that has reached the generally accepted maximum size for that
cultivars or
species. See
Juvenile |
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mealybug |
- a small
insect about ¼ inch long that is covered with
white, waxy fibers that give it a fuzzy appearance. It
is a sucking insect that draws sap from the plant and
can be destructive in large numbers. |
mechanical injury |
- damage to a plant caused by forces other than disease
including lawnmowers, winds, ice, pruning, etc. |
medial
variegation |
- a leaf or leaves having
a lighter colored center as compared to the edges i.e.
margin, color. |
medio-variegated |
- See medial variegation above. |
medium |
-
See growing medium or
media |
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medium size |
- according to the
The American Hosta Society, there are
five size categories of
hosta including
Giant,
Large,
Medium,
Small and
Miniature. Medium
hostas form a clump that is
10 to 18 inches in height and a leaf area of 25 to 81 square
inches. |
melting out |
- the death (necrosis)
of the white or lighter colored center of
hosta leaves. This may
be caused by excessive sunlight or may be the result of cold
temperatures. |
meristem |
- this is the tissue in plants that has the ability to
produce new cells. The cambium, root tips and
buds of
plants contain these cells and are the centers of
growth. (adj. meristematic) |
metamorphosis |
- the process by which
insects proceed from egg form to adult form. Some
insects go through complete metamorphosis where early
stages look nothing like the adult. White grubs
eventually becoming
beetles is an example.
Others have incomplete
metamorphosis where the young form merely gets larger to
become the adult. A newborn grasshopper looks like and
adult, only smaller. |
microclimate |
- localized conditions in the landscape can result in
variations from the average climate in the surrounding region.
Topography, exposure to wind or sun, proximity to
buildings or fences, urban conditions, etc. are factors
which may change the climate of a small site in the home
landscape. |
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micro-nutrient or
micro-element |
- there are certain mineral elements that are essential
for plant growth. Some of these
nutrients are needed in
relatively large amounts for plant growth and these are
the macro-nutrients. Others,
micro-nutrients, are required in relatively small amounts
but both groups are essential for proper, healthy plant
growth. This group includes
Boron (B),
Copper (Cu),
Chlorine (Cl),
Iron (Fe),
Manganese (Mn),
Molybdenum (Mo), and
Zinc (Zn).
Generally, these are in adequate supply in the soil.
However, a deficiency of
these elements will result in specific symptoms on the
plant. Also, excessive amounts may result in
toxicity to the
plant.
They occasionally need to be supplemented but
only if shown by the results of a
soil
test.
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micro-pore |
- a pore is an opening or hollow space in the soil. Some
of them are relatively large and are called macro-pores
while other are quite small and are known as
micro-pores. Generally, in the soil, micro-pores are
filled with either air or water which is held tightly to
the surrounding surfaces.
- See soil pore spaces. |
mid-rib |
- center vein of a leaf. It is
also called the medio or medial area of the leaf. |
mineral soil |
- soil made up principally of weathered rock
particles such as sand,
silt and clay. See
organic
soil. |
miniature size |
- according to the
The American Hosta Society, there are
five size categories of
hosta including
Giant,
Large,
Medium,
Small and
Miniature. Miniature
hostas are the second
smallest group. They form clumps that are 4 to 6 inches in
height. |
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misted |
- 1) Misted colored leaves have small, short
segments of dark pigmented tissue on a lighter background. 2)
May refer to the application of short periods of sprayed
water to keep hardwood or sometimes, softwood
cuttings
moist to encourage rooting. |
mites |
See spider mites |
miticide |
- the suffix, icide, means "to kill". Miticides
are meant to kill the eight legged creatures called
spider mites. These
products are somewhat different from
insecticides which are
meant to kill the six legged critters called insects. |
monocotyledon |
- a cotyledon is a "seed leaf" and seed bearing plants can be divided generally into
two groups. Monocotyledons (generally grasses and grass-like
plants) and dicotyledons (all other seed bearing plants).
Somewhat ironically,
hostas are monocotyledons even
though many of them have very large, non-grass-like
leaves.
Monocotyledon |
Dicotyledon |
Embryo with single cotyledon |
Embryo with two cotyledons |
Pollen with single furrow or pore |
Pollen with three furrows or pores |
Flower parts in multiples of three |
Flower parts in multiples of four or
five |
Major leaf veins parallel |
Major leaf veins reticulated (webbed) |
Stem vascular bundles scattered |
Stem vascular bundles in a ring |
Roots are adventitious |
Roots develop from radicle |
Secondary growth absent |
Secondary growth often present |
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monoculture |
-
growing one species of plant in an area to the exclusion
of others. This results in a higher possibility of a
serious
insect or
disease problems causing severe devastation.
For example - At one time, many city streets were lined exclusively with American
elm (Ulmus americana) trees. When
Dutch elm
disease was introduced to the
United States in the 1950s, it swept through these areas
quickly killing almost all of this species of tree. |
monoecious |
- bearing separate male (staminate) and female (pistillate)
flowers on the same plant.
Oak trees produce separate flowers as
does sweet corn where the tassel is the male flower and
the silk is the female. Examples include Birch (Betula),
Hornbeam (Carpinus),
Hophornbeam (Ostrya),
Hickory (Carya),
Oak (Quercus),
Beech (Fagus).
See
dioecious. |
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Morden |
- a common cultivar name for plants originated at the
Canada Experimental Farm at Morden in Manitoba,
Canada. |
mosaic |
- the common symptom caused by a virus infection of
plant tissue. Also called mottling because it consist of
non-uniform streaks and patches of yellow intermingled
with the normal green color of the leaf or stem. The
variegation of certain plants or
cultivars may be caused
by a virus. Hosta 'Cynthia' exhibits this trait. Plants infected
with a virus may also display a mottled color pattern
but some
hosta cultivars that are mottled do not have a
virus. |
mottled |
See mosaic above. |
mucronate |
- coming abruptly to a sharp point. The leaves of
certain hostas have a distinct point at the end which
would be described as "mucronate". |
mulch |
- any material used to cover the soil for purposes
such as moisture conservation, esthetics, cooling the
soil or weed suppression.
The material
may be wood chips, shredded bark, peanut hulls, cocoa
bean hulls,
peat moss, leaf-mould, garden
compost, landscape cloth or
plastic sheeting
among
others. |
mutation |
- applies to a "spontaneous" change to the genetic
material (DNA) of an individual which may be passed from
generation to generation through
sexual reproduction. |
mycoplasma |
- these are a type of bacteria that do not have cell
walls and are extremely small that occasionally cause
plant disease. |
mycorrhizae |
- a type of soil fungus that forms a symbiotic (mutually
beneficial) relationship with the roots of certain
plants. When this fungus is growing on the root, it
helps the plant to more efficiently absorb
nutrients and water.
Generally, a specific fungal species works on a
specific tree species. Efforts are being made to isolate
these fungi and make them
commercially available to be placed in the
transplant hole for specific trees. |
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