Download Plant kingdom

From: http://www.perspective.com/nature/plantae/
Plants provide nourishment for our bodies and souls. With the help of protists and fungi, plants provide the oxygen
we breathe and the food that sustains us -- either directly or indirectly, by feeding other animals. Plants provide shade
over our heads and cool carpets under our feet while surrounding us with beautiful colors and marking the change of
seasons.
Prominent plants give us a handle on ecological communities. Descriptions such as "Redwood-Tanoak Forest" or
"Oak Grassland" indicate not only the plants we may find there but the animals, fungi, and climate as well.
Classification of the plant kingdom can be especially confusing to the amateur naturalist. For example, according to
modern botany:
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A palm tree has more in common with a blade of grass than with other trees.
A strawberry plant is more closely related to an apple or apricot tree than to a clover or geranium.
A Ginko (Maidenhair) tree is so different from other plants that it is in a phylum by itself. But if you
have to group it with other plants, it belongs with conifers such as Pine trees.
At least four classification systems are in common use: Plants are classified into 12 phyla or divisions based largely
on reproductive characteristics; they are classified by tissue structure into non-vascular (mosses) and vascular plants
(all others); by "seed" structure into those that reproduce through naked seeds, covered seeds, or spores; or by
stature divided into mosses, ferns, shrubs and vines, trees, and herbs.
All of these higher-level groupings are decidedly lopsided: the vast majority of the 270,000 plant species are
flowering herbs. The categories listed below provide slightly better balance: the largest phylum has been split while
the other phyla are grouped according to one or more of the methods described above.
Mosses and Allies (Bryophyta and allies)
Mosses are non-vascular plants -- they cannot transport fluids through their
bodies. Instead, they must rely on surrounding moisture to do this job for them.
Though small in stature, mosses are very important members of our ecosystem.
They lay the foundations for other plant growth, prevent erosion, and
contribute to the lush green appearance of many forested areas.
The 24,000 bryophyte species, sometimes grouped into a single phylum are
now grouped in three phyla: Mosses (Bryophyta), Liverworts (Hepatophyta)
and Hornworts (Anthoceraphyta). They reproduce by spores, never have
flowers, and can be found growing on the ground, on rocks, and on other
plants.
All plants reproduce through alternating generations. Nowhere is this more
apparent than in the mosses. The first generation, the gametophyte, forms the green leafy structure we ordinarily
associate with moss. It produces a sperm and an egg (the gametes) which unite, when conditions are right, to grow
into the next generation: the sporophyte or spore-bearing structure.
The moss sporophyte is typically a capsule growing on the end of a stalk called the seta. The sporophyte contains no
clorophyl of its own: it grows parasitically on its gametophyte mother. As the sporophyte dries out, the capsule
release spores which will grow into a new generation of gametophytes, if they germinate.
Mosses, the most common, diverse and advanced brypophytes, are categorized into three classes: Peat Mosses
(Sphagnopsida), Granite Mosses (Andreaopsida), and "True" Mosses (Bryopsida or Musci).
Leafy Liverworts (Phylum: Hepatophyta, Class: Jungermanniidae)
While people typically know what a moss is, few have even heard of
liverworts and hornworts.
These primitive plants function much like mosses and grow in the same places,
often intertwined with each other. The liverworts take on one of two general
forms, comprising the two classes of liverworts: Jungermanniidea are leafy,
like moss; Marchantiopsida are leaf-like (thalloid) similar to foliose lichens.
The leafy liverworts look very much like mosses and, in fact, are difficult to
tell apart when only gametophytes are present. The "leaves," however, are
simpler than moss and dont have a midrib (costa). The stalk of the sporophyte
is translucent to white; its capsule is typically black and egg-shaped. When it
matures, the capsule splits open into four equal quarters, releasing the spores to
the air.
The liverwort sporophyte shrivels up and disappears shortly after releasing its spores. Because of this one hardly ever
sees liverwort sporophytes out of season. Moss sporophtyes, on the other hand, may persist much longer.
Shown: Class: Jungermanniidea; Order: Jungermanniales; Family: Scapaniaceae; Scapania spp. (probably)
Leaf-like Liverworts (Phylum: Hepatophyta; Class: Marchantiopsida)
The leaf-like (thalloid) liverworts are, on the whole, more substantial and
easier to find than their leafy counterparts. The gametophyte is flat, green and
more-or-less strap-shaped. The body may, however, branch out several times
to round out the form.
When the gametophyte has become fertilized and is ready to produce its
sporophyte generation it may grow a tall green umbrella-shaped structure
called the carpocephalum. The sporophyte grows on the underside of this
structure, often completely hidden from view.
During the dry season, leaf-like liverworts may shrivel up and disappear from
view until the rains arrive again.
Thalloid liverworts are much easier to identify than their leafy counterparts
due to the wider variety of gametophyte shapes.
Shown: Class: Marchnatiopsida; Order: Marchantiales; Family: Aytoniaceae; Asterella californica
Hornworts (Phylum: Anthoceraphyta)
Hornworts are very similar to liverworts but differ in the shape of the
sporophyte generation. Instead of generating spores in a capsule atop a
stalk, the hornwort generates spores inside a green horn-like stalk.
When the spores mature the stalk splits, releasing the spores.
Under the microscope, hornwort cells look quite distinct as well: they
have a single, large chloroplast in each cell. Other plants typically have
many small chloroplasts per cell. This structure imparts a particular
quality of color and translucency to the body (thallus) of the plant.
Hornworts are all grouped into a single class, Anthocerotae, containing
a single order, Anthocerotales.
Fernsand Allies (Pteridophyta and allies)
Ferns and allies have a vascular system to transport fluids through their bodies
but like the mosses, they reproduce from spores rather than seeds. The main
phylum, the Ferns (Filicinophyta = Pteridophyta) includes around 12,000
species.
Three other phyla are included as fern allies: the Horsetails (Sphenophyta = Equisetophyta, 40
species; right, accompanied by an orchid), Club mosses (Lycopodophyta, 1,000 species), and
Whisk ferns (Psilophyta, 3 species)
Ferns represent the second major step in the evolutionary sophistication of plants. While they still reproduce by spores
like mosses, the ferns add a vascular system -- i.e. specialized organs for trasporting fluids throughout the plant.
As an inidication of this extra evolution, the gametophyte stage of growth is significantly reduced. In this way, a fern
can be thought of as the inverse of a moss. The moss plants we commonly see are gametophytes: the sporophyte stage
is small and often overlooked. By contrast, the fern plants we commonly see are the sporophytes: it is the
gametophyte stage that is small and often overlooked.
Ferns have a horticulural value in our society -- i.e. people are willing to consider intentionally adding ferns to our
outdoor and indoor gardens -- and therefore we know more about them. Perhaps size is also a factor: ferns are big
enough to catch our divided attention while we hike along a trail. Modern flora usually include keys for identifying
ferns as well, thus further increasing their exposure to our roaming curiosity.
The gametophyte generation of ferns are small,
heart-shaped, plants called prothallia (singular:
prothallium). They are less than an inch (1 - 2
cm) in diameter and look very much like
thalloid liverworts or hornworts. Male and
female sex organs are located on the underside
of the prothallium and, when conditions are
right, the sperm swims from the male antheridium to fertilize the egg
in the archegonium.
The result of this union is the fern plant we have come to know and
recognize. This plant, the sporophyte, grows to maturity and then
produces spores on the undersurface of its leaves or fronds. Fern
sporophytes can grow as tall as trees. They can reproduce vegetatively
from root cuttings. They never have flowers.
Ferns prefer to live in environments having low light and relatively high levels of moisture and humidity and. For
reason they flourish in tropical forests. In fact, regardless of where they are, an abundance of ferns imparts an
impression of the topical forests to human observers.
Fern allies share the characteristics described here but do not have the ferns' stem and leaf structure. The most
conspicuous of these allies is the Horse-tail plant.
Conifers and Allies (Gymnosperms = Coniferophyta and)
The gymnosperms add the next level of complexity to plant evolution: they reproduce from seeds
instead of spores. The seeds, however, are "naked" (Greek: gummnos) -- not covered by an ovary.
Usually, the seed is produced inside a cone-like structure such as a pine cone hence the name
"conifer." Some conifers, such as the Yew and Ginko, produce their seeds inside a berry-like
structure.
Conifers are fairly easy to identify: In addition to the aforementioned cones, these trees and shrubs typically have
needle-like, scale-like or awl-like leaves. And they never have flowers.
Approximately 600 species are counted as conifers including the pines, firs, spruces, cedars, junipers, and yew.
Species within the conifer ranks give us pine nuts -- pesto's magic ingredient -- as well as juniper berries for gin.
Conifer allies include three small phyla containing fewer than 200 species all together: Ginko (Ginkophyta) with a
single species: the Maidenhair Tree (Ginko biloba); palm-like Cycads (Cycadophyta) ; and herb-like cone-bearing
plants (Gnetophyta) such as Ephedra.
Flowering Dicot Plants (Angiospermophyta, Class Dicotyledoneae)
Angiosperms add the final improvement to plant reproduction: they grow their seeds inside an
ovary (Greek: angeion = vessel) which is, itself, embedded in a flower. After it is fertilized, the
flower falls away and the ovary swells to become a fruit.
Angiosperms in the class Dicotyledoneae grow two seed-leaves (cotyledons). In addition, foliage
leaves typically have a single, branching, main vein originating at the base of the leaf blade, or
three or more main veins that diverge from the base.
The vast majority of plants are Dicots. Most trees, shrubs, vines, and flowers belong to this group of around 200,000
species. Most fruits, vegetables and legumes come from this class.
(Angiospermophyta is also called Anthophyta or Magnoliophyta)
The class Dicotylodonea is large and diverse. Dicot plants range from tiny plants to tremendous trees; fleshy
succulents to delicate herbs that dry out almost as soon as they're picked; large and complex flower heads to tiny
flowers that barely deserve the name; annuals and perenials; deciduous and evergreen. Each plant can be described
with 100 features including size, shape, color, and features of the entire plant, leaves, flowers, and fruit.
Around 300 families of flowering plants are currently identified as Dicots. Learning the intricacies of the Subclasses,
Superorders, and Orders is of limited value for the typical naturalist. Nevertheless, the Family groupings are quite
helpful.
Here are some of the most prominent herb and shrub families in our region and probably most temperate areas.
Sunflower Family (Asteraceae)
The Sunflower family contains the largest number of plant species in the San Francisco Bay Area
and many other parts of the world. The Sunflower family includes shrubs such as Coyotebrush as
well as herbs such as Sunflowers, Daisies, Asters, Thistles, and Dandelions.
All of these plants have compound flower heads. While it appears to be a single flower, closer
examination reveals that the head is composed of many separate flowers: tiny five-petalled "disk
flowers" in the center and/or single-petalled "ray flowers" around the outside. Dandelions have only ray flowers;
Thistles and Coyotebrush have only disk flowers; Sunflowers and Daisies have both. While the compound flower
feature makes Sunflower species easy to recognize, these plants are notoriously difficult to identify beyond the family
level. Luckily not all Sunflower members are so difficult to distinguish -- the pretty Tidytips (Layia platyglossa)
shown here are quite distinctive, for example.
Pea family (Fabaceae)
Pea family members seem to be everywhere in San Francisco Bay Area grasslands. The family
includes the Acacia trees found both in and out of cultivation; shrubs such as Lupine (left), Broom,
and Gorse; as well as the herbacious Vetch and Clovers.
Pea fruit grow in a their distinctive pod shape; the flowers of the Pea family are typically
distinctive as well. The flower has a banner petal above, two wing petals on either side, and a keel
consisting of two fused petals below. The keel is often hidden between the wing petals, as in the
Lupine (Lupinus nanus) flower shown here, in which the wings of the flower to the left of the stem were pulled down
to reveal the keel.
Geranium Family (Geraniaceae)
Although we have only a small number of wild Geranium species in the Bay Area, they make up in
number what they lack in diversity. And then, of course, there is the Pelargonium genus from
which our cultivated Geraniums derive.
Geraniums typically have five petals, five or ten stamens and a pistil in five sections that split apart
when the fruit matures. The Erodium genus uses this last feature in a most interesting way... Check
it out!
Pictured here is the Cinquefoil Geranium (Geranium potentilloides), a common springtime flower in our grassy hills.
Carrot or Parsley Family (Apiaceae)
The carrot family brings us many culinary herbs such as parsley, coriander, fennel, and dill; as well
as roots such as parsnip and, of course, carrots. Poison Hemlock -- which earned its place in
Western history when Socrates drank a cup-- is also a member of the carrot family.
Many early Spring flowers -- such as the Footsteps-of-Spring (Sanicula arctopoides) displayed
here -- are members of this family; Sanicle foliage lines shaded mountain paths starting in mid
Winter.
Carrot members are typified by dense clusters (umbels) of tiny five-petalled flowers.
Rose Family (Rosaceae)
The Rose family may well be the most important Dicot family, commercially. Roses themselves, of
course, are cherished for their beauty, whether in a garden or a boquet. Many fleshy fruit such as
strawberries and raspberries, apples, oranges, cherries and plums also belong to Rosaceae.
In the wild, various other Rose species add beauty to the environment. In early Spring, wild
Strawberry plants make a strong showing in our area; later in the Summer shrubs such as
Blackberry, Thimbleberry, and Salmonberry provide tasty trailside treats. Chamise (Greasewood, Chapparal)
dominates parts of our chapparal environment, while Toyon (Christmasberry) is common in more open areas.
Rose flowers (its namesake Genus notwithstanding) are typically five-petalled with many stamens and sometimes
many pistils as well -- such as in the Thimbleberry (Rubus parviflorus) pictured here.
Purslane Family (Portulacaceae)
While small in number of species, this family contains some of my favorite edibles including
Miner's Lettuce and Common Purslane, as well as the very pretty Redmaid flowers.
Purslane members are distinctive because they have only two sepals for their five-petalled flowers,
as can be seen in this close-up of Miner's Lettuce (look carefully at the partially open flowers to see
the sepals).
Heath Family (Ericaceae)
The Heath family includes trees such as Madrone (pictured left), shrubs such as Blueberry,
Manzanita, and Rhododendrons/Azaleas as well as numerous herbacious plants.
Many Heath species have beautiful urn-shaped flowers. All Heaths are dependent on fungi in order
to survive.
Adding the Buttercup, Snapdragon, Mustard, Poppy, and Evening-primrose families would round out this group to an
even dozen: knowing them personally would be a most rewarding experience. And then there's the Mint, Mallow,
Oak, Borage, Pink, Waterleaf, Phlox and many more families -- all equally enjoyable. But you have to start
somewhere.
Flowering Monocot Plants (Angiospermophyta, Class Monocotyledoneae) Monocots start with one seed-leaf. The main veins of their foliage leaves are usually unbranched
and nearly parallel to each other. Around 30,000 plants are classified as monocots including many
of the prettiest members of kingdom Plantae: orchids, lilies, irises, palms and even the Bird-ofParadise plant. The grasses which carpet our lawns and meadows are also monocots.
Monocots provide us with our primary sources of nutrition, supplying us and the animals we eat
with grains such as wheat, oats, and corn, as well as fruits such as dates and bananas.
The Soap-plant or Amole (Chlorogalum pomeridianum) is an unassuming
plant with a very rich history. Its elegant evening flower display is as easily
overlooked as its history .
California Indians apparently used this relative of the onion for everything
from cleaning up to fishing (the crushed leaves stun the fish), and even for
curing rheumatism. Around the turn of the 20th century one V.K. Chestnut
even claimed that the soapy juice of its onion-like bulb could cure Poison Oak.
The bulb remains in the ground for several years, producing leaves early each year -- the photo to the left was taken in
February; the one at the bottom of the page in January. The Amole to the left was growing on the side of a trail which
had eroded just enough to expose half of its mature bulb, thus revealing the deception of its young shoots. The
exposed bulb was around 4" (10 cm) tall, with the leaves growing another 2" (5 cm) or so above that.
Although the new foliage arrives very early in the year the Amole doesn't flower until mid-Summer. Beginning
around July, the plant sends up a central stalk with many buds growing along branchlets in a panicle arrangement.
Late each afternoon one row of buds opens, starting from the bottom. The
delicate white flowers twist closed by evening and never open again. Each
day another row, opens then wrings itself closed forever. If you look
carefully at the photo at the top of this page you will see the twisted bloom
of the previous day to the right, and the unopened new bud to the left of the
open flower.
The thin branches supporting the flowers fade into the background making
it seem as if the flowers are floating in thin air.
Below: Before producing its blooms, the Soap-plant can be recognized by
its wavy leaves which are folded lengthwise. Some plants sport leaves with
a red border. The photos on this page are of Chlorogalum pomeridianum
var pomeridianum.