Botany Primer For Gardeners

Botany Primer for Gardeners Linda R McMahan, PhD Botanist & Extension Horticulturist Oregon State University Extension linda.mcmahan@oregonstate.edu

What We Will Cover Plant Diversity Algae, fungi and lichens Spore producing plants – mosses, liverworts, ferns Seed plants – conifers, ginkgo, and flowering plants Plant Structure and Growth Stems and roots Leaf structure Flowers and reproduction

Plant Diversity From ancient time when we began studying the world around us, we tried to understand our surroundings by labeling plants and animals Our current scientific understanding continues to refine relationships, but historically, many organisms have been considered to be plants even if they are not now considered to be so I will use the historic understanding and explain modern differences as we proceed

Plant Diversity The classification of various kinds of plants is based on reproduction Spore producing plants appeared on earth before seed producing plants Later, seed plants became more common—these are also the ones most common in our landscapes and gardens

Plant Diversity Goal: Learning the patterns of diversity will help us learn to garden with nature rather than working against it Fallen leaves inside umbrella plant, Darmerapeltatum

I. Organisms that reproduce through spores Algae and fungi Lichens Slime Molds Mosses Liverworts and relatives Horsetails Ferns Sori, the spore carrying bodies on ferns, here a sword fern

Algae and Fungi Some algae are considered to be plants and some are not--fungi now reside in a separate Kingdom but many people think of them as plants Both reproduce using some form of spore or similar structure

Algae Include many different kinds, but the most familiar are those of streams, ponds and at the ocean shore washed up on the sand or growing on rocky shores

Are Algae A Problem? Algae by themselves are not a problem-it is not a parasite for example Because growth of algae requires moisture and nutrients, it will grow where these are available, such as polluted streams. Algae grows in nutrient rich streams and on sidewalks because it can find required nutrients there. Control may be necessary for safety or other reasons, but the algae itself is not the cause of the harm, they just take advantage of the conditions.

Fungi Many kinds of fungi occur on earth When you say “fungus”, most people will answer “mushroom” but fungi are much more complex As we shall see, by far the most fungi are beneficial organisms but a few do cause diseases which are of concern to gardeners It is important to distinguish between different kinds and not label all fungi as “bad”

Fungi Some mushrooms and other fungi are also toxic, but this is rarely a concern. Unless you know they are a problem, please don’t treat mushrooms with fungicides because this will interfere with their positive interactions with plants and the environment. For controlling fungi that cause disease, follow the recommendations of your local or state cooperative extension office.

Mushrooms in the Lawn Gardeners who are worried about safety can seek positive identification and information, or rake up the mushrooms and discard or compost them

Positive Benefits of Fungi Fungi are one of earth’s major decomposers, helping to return organic matter to enrich our soils Soil fungi form mutually beneficial relationships with plants called mycorrhizae

How Fungi Reproduce Fungi reproduce through spores that become airborne The visible part of a fungus is usually the spore-producing body The larger mass of the fungus is fine fungal strands that are often underground or inside a decaying organism A “mushroom” is one kind of fungal spore producing body

Fungi Mushrooms and other spore producing bodies are often the most visible part of the fungus Mushrooms growing in an arc or ring are sometimes called a “fairy ring” Yellow houseplant mushroom

Not all spore producing bodies are “mushrooms” Cup-like spore producing bodies in cracks in a brick walkway Cup style spore bodies in moss on a decaying branch

Mycorrhizae Most soil fungi form relationships with most plants in a mutually beneficial relationship called mycorrhizae Perhaps every plant shown in this forest clearing has associations with soil fungi

Mycorrhizae Mycorrhizae are found in the roots of the plants where tissues of the two organisms intertwine Fungal strands are in contact with the soil and extend the absorption capacity of the roots Fungi gain the benefit of photosynthetic nutrients made by the plants

A new way to look at forests and gardens Part of the magic of this relationship is that individual plants may form associations with dozens of different fungi And, each fungus may form associations with dozens of trees Together, these create a network of interactions

Slime Molds Slime molds are not technically fungi nor plants They grow in moist, usually warm conditions such as forests and damp gardens They are another form of decomposer but can alarm people who have not seen them before Slime mold spore producing bodies on turf grass. Oregon State University Plant Clinic

Slime molds in the garden Slime molds have two phases. A moving mass first grows on decaying leaves, compost, or stumps. The spore producing phase is harder and often colorful. Both phases are ephemeral, disappearing only a few days or weeks after their appearance. Spore producing structures of a slime mold on the back of an oak leaf

Lichens, a “special” group Lichens are usually small and are not individual organisms Instead, they are a combination of two different organisms—one is a fungus, and the other is algae British soldiers, a ground dwelling lichen

Lichens Most are gray or greenish The visible part is the fungus, the algae are inside Lichens are another mutually beneficial relationship Several kinds of lichens on a tree branch

Lichens Both algal and fungal partners benefit from this relationship Algae gain a moist environment and the fungus gains photosynthetic nutrients Together, they inhabit places like this rock where neither could if they were alone Lichens growing on a rock

Lichens Some gardeners are worried about lichen, but they are not a disease and cause no harm to the plant Various lichens are indicative of good or bad air quality, an aid to understanding our environment White and brown lichen on a tree trunk

Mosses Are common in the moist habitats Reproduce by spores Are of short stature because they lack an organized vascular system to move water and nutrients Help maintain moisture and provide homes for small creatures Mosses and tiny mushrooms on a downed log

Mosses Mosses are a healthy part of gardens and ecosystems They often grow in lawns when the lawns themselves are not robust Mosses are opportunists and will grow wherever the habitat is appropriate

Liverworts and other forest floor plants Liverworts and their relatives have been on earth since ancient times They reproduce by spores They usually grow in natural habitats but sometimes can be found in gardens They are not harmful in a garden setting Selaginella, usually a forest dweller

Liverworts One species of liverwort has become adapted to live in nursery pots and is considered to be a pest by nursery owners Once in the garden, they usually disappear after a time and cause no harm

Horsetails Perhaps no plant has caused such concern to tidy gardeners as the common horsetail. Rapidly spreading underground in a favorable environment, this plant can become quite a pest. Horsetail, Equisetum, showing the spore producing branches that appear before the typical green branches

Horsetails Here is the familiar horsetail form Horsetails of many kinds are native around the world Control is usually through persistent hand weeding or tolerance

Ferns Ferns also reproduce by spores Ferns are popular garden plants and some forms thrive in most, shady garden conditions Licorice fern growing on a tree trunk

Ferns Typically the fern leaves, called fronds, uncurl as they open such as shown here Bracken fern in spring

Ferns Spores are produced on the backs of the fronds or sometimes on separate modified leaves that only bear spores Sword fern spore bodies

2. Plants that produce seeds We will cover three kinds of seed bearing plants Ginkgo Conifers Flowering Plants Fruits of red osier dogwood, a flowering plant

Ginkgo Very ancient plants once though to be extinct Related to conifers but have different reproductive structures They are neither conifers nor flowering plants but in a group all their own Fall foliage and seed bearing structures on a mature female tree

Ginkgo biloba Good landscape tree, drought and pollution tolerant Distinctive leaf form often used in artistic work Native to China

Conifers Bear their seeds in cones Conifers also have needles or scales When seeds mature, cones usually open

Conifers Large group with many trees and shrubs Popular in gardens, particallybecause most are evergreen Pines, firs, cedars, juniper, larch, and many more An ornamental conifer with colorful cones

Conifers Cones are made up of overlaping scales In new female cones, the ovules are inside the cone but the scales are open to allow pollination After pollination, the scales usually close while the seeds mature Cone on an ornamental larch

Conifers Pollination time differs for each species Pollen is produced in tiny cones (dark orange in this tree) which is transferred by the wind to the tiny female cones at the tips of the branches New cones and year-old cones on a pine species

Flowering Plants A very large group, the latest to appear on earth Developing seeds are protected within a solid structure which becomes a fruit Pollen must actually grow through tissue to fertilize the ovum

Flowering Plants Include trees, shrubs, herbaceous plants, vines Are very popular garden plants Are highly adapted to particular forms of pollination Many have very close mutually beneficial relationships with insect pollinators Gaillardia or blanket flower attracts bees and butterflies

Pollination Is the process of transferring pollen from one flower to another Typically, can be by wind, insects, water, birds, bats, or human intervention Honey bee pollinating a Ceanothus flower

Pollination Plants pollinated by insects are typically sweet smelling, colorful, and have places for insects to land The “reward” for pollination is food from nectar or pollen Bumblebee on an aster

Pollination Plants attracting butterflies also provide nectar—they often have a large flat surface to support the butterfly’s body Butterfly pollinated plants often have “butterfly partners” that use the plant as places to lay their eggs

Pollination Many other garden plants are pollinated by hummingbirds These flowers tend to be red or orange Birds can see these colors but bees cannot Red columbine, Aquilegia canadensis

Pollination Plants pollinated by wind have less colorful flowers Pollen is usually produced in catkins which contain only male flowers Pollen is carried by the wind to female flowers that produce seeds Catkins on a willow

Fruits When seeds mature, they are carried in fruits Fruits can be fleshy or dry and take many forms Berries as shown here are one type of fruit Calicarpa americana, the American beautyberry

More Fruits Mimulus guttatus, yellow monkey flower has dry fruits called pods Big leaf maple, Acer macrophyllum has dry fruits called samaras

3. Plant Anatomy Seed bearing plants all share the same basic structures Typical parts include leaves, stems, roots, and flowers Differences are in the “details” which help us tell one plant from another

Overall Plant Structure This is sweet cicely, a plant native to Oregon Botanists know this because it has white flower heads, each with many flowers of a certain type Another clue is the finely divided leaves in a particular pattern

Stems Provide overall support Create the “architecture” characteristic of each plant Have internal vascular systems for transport of water, minerals, and photosynthetic nutrients

Stem Structure This stem is woody, with wood cells for support The main stem has a side branch at a place called a node The side branch has two buds, one at the end – a terminal bud, and one on the side, called a lateral bud

Stem Structure Here is another winter twig with no leaves Plants that loose leaves during dormancy are called deciduous Note the leaf scars on the side where the leaves fell off in the fall Also note that the terminal bud has scales

Stem Structure Each year, when the buds break or start to grow, the bud scales fall off, leaving bud scale scars If you look carefully, you can sometimes see these scars circling the branch This helps us determine which is this year’s growth and which is last year’s

Plant Growth Structure Buds are of many types including flower buds, branch buds, and mixed buds Lateral branch or mixed buds can grow into branches under the right conditions

Plant Growth Structure Note that the small branch is growing from a node area, just above the leaf The buds that produce branches are usually in this location, leading to another name: axillarybud

Kinds of Branching The kind of branching on the last slide is called alternate Here, the type of branching is called opposite The kind of leaf pattern and branching pattern leads to different shapes of plants

Woody Stems Woody plants grow differently than herbaceous plants Herbaceous plants are most commonly annuals, biennials, or perennials, which create new aerial growth each year

Woody Stems Here is a cross-section through a tree, showing typical woody structure On the outside is bark Right inside the bark is tissue called phloem that actively transports photosynthetic nutrients

Woody Plants The inner part is xylem tissue that transports water and is considered to be the “woody part” This is also where we see growth rings, which can indicate the age of the tree

Woody Plants One growth ring is formed each year At the beginning of each growth season, cells are large At the end of the season, they are smaller and more dense, leading to the darker “rings” The oldest growth of the tree is in the center

Woody Plants Nutrient and water transport happen on the outer edges of the tree or shrub For this reason, it is important to protect the bark; injury can lead to disruptions of nutrient and water flow and growth

Leaves Leaves are usually the site of the process of photosynthesis, using the sun’s energy to create sugars and other nutrients They also have unique patterns that help us identify plants

Leaf Characteristics – Vein Patterns The vascular system of plants moves through leaves in 3 kinds of patterns The pattern shown here is called a parallel vein pattern Parallel veins on a lily plant

Parallel Vein Patterns Parallel vein patterns Occur in a group of plants called Monocotyledons or “Monocots” for short They include grasses, lilies, onions, and many other related groups

More Parallel Vein Patterns Mianthemum dilitatum, false lily of the valley Disporum species

Pinnately Veined Vein patters are also sometimes called venation Pinnatelyveined leaves have veins in a feather-like pattern This is a common pattern and signifies that the plant is in the group Dicotyledon or “Dicots” for short

More Pinnate Vein Patterns Leaf skeleton of a magnolia

Palmately Veined Leaves Palmately veined leaves are the third pattern Main veins arise from the point of attachment, sort of like the fingers from the palm of a hand These are also found in the group called “Dicots” Coltsfoot

More PalmatelyVeined Leaves Fringecup, Tellima gandiflora A water lily

Petioles Most leaves have a stem like structure connecting the leaf blade to the stem These are called petioles Some leaves do not have petioles, which helps us distinguish one plant from another

Leaf Edges Patterns of leaf edges also help us distinguish plants This is one of many edge patterns or margins This one is called a toothed margin

Simple Leaves Leaves with just one undivided leaf blade are called simple leaves Several simple leaves on a branch are shown here Oceanspray, Holodiscus discolor

Simple Leaves Remember, each leaf has a bud associated with it to facilitate branching Several leaves and the associated axillary buds are shown here Salal, Gaultheria shallon

Compound Leaves Compound leaves have more than one blade, each is called a leaflet There are several patterns of compound leaves, this one is pinnately compound and has 7 leaflets Oregon ash, Fraxinus latifolius

Compound Leaves Here is another example of a pinnately compound leaf Remember, you can determine what is a leaf by looking for the bud at its base This plant gives us a clue because the entire leaf is reddish- it has 11 leaflets Berberis nervosa, long leaf Oregon grape

Compound Leaves Another pattern is palmately compound leaves This one has 7 leaflets

Compound Leaves Once again, the way to tell a leaf from a leaflet is to look for the axillary bud This is difficult to determine in a photographs but is usually much easier in a hand-held sample Wild lupine

Compound Leaves One more pattern is also common and is doubly compound This particular pattern is called bipinnately compound Sometimes they are described as finely divided in herbaceous species

Leaf Adaptations Leaves can be modified to perform many different functions These leaves are modified to catch insects in an insectivorous plant California pitcher plant, Darlingtoniacalifornica

Modified Leaves This Pacific Northwest native plant has leaves modified for vegetative reproduction Piggyback plant, Tolmiea menziesii

More Modified Leaves Floating leaves on a water lily Spines on a cactus

Roots Since roots are underground, we seldom think about their presence Major functions include support, absorption of water and minerals, and storage of carbohydrates and other photosynthetic nutrients Large underground storage root of the wild cucumber

Roots Even though we do not usually see roots, they are sometimes massive structures underground For example, roots of this ash tree, and even the herbaceous plants beneath it, will extend many feet beyond the canopy of the above ground part of the plant Veratrum emerging in the spring next to the trunk of an Oregon ash, Fraxinus latifolius

Roots Woody plants also have woody roots Clip art showing roots of a tree

Roots Carrots, like those shown here in a pretend bunny, are tap roots. Their main structure is a single enlarged root with smaller roots off the surface Tap roots often serve as storage for carbohydrates and other nutrients

Roots Roots of many if not most herbaceous plants are fibrous, such as in this bulb Clip art

Flowers and Fruits The existence of flowers is one of the reasons we garden Even vegetable gardens usually require flowers because fruits cannot form without them passionflower

Flowers The purpose of flowers is to produce seeds A side product is that gardeners and pollinators can enjoy the benefits they provide Flowers of Rosa nutkana (Nutka rose) and Physocarpus capitatus (ninebark)

Flowers A typical flower has four countable parts: Sepals, petals, stamens and pistils Sepals and petals are the outer parts—sepals are usually green and petals are usually colorful

Flowers Many flowers are not typical In this iris, for example, the three smaller petal-like structures are acutally sepals. The larger three are the petals

Flowers This trillium has the more typical pattern with three green sepals and three white petals The sepals are the outer layer of a flower and usually cover the flower bud before it opens Both iris and trillium are Monocots Trillium ovatum

Monocot Flowers Plants with flower parts in groups of 3 or multiples of 3 are usually in the subgroup Monocots Note the parallel venation on this plant, which support that classification Slinkpod, Scoliopus bigelovii

Dicot Flowers Flowers with flower parts in groups of 2,4,5 or multiples are usually Dicots This flower has 4 petals so is most likely a Dicot Notice that the central stigma (we will cover those later) is also split into 4 at the tip Flower of a Clarkia species

Dicot Flowers These flowers also have 4 petals Look for the 4 smaller sepals Also note the vein pattern is pinnate This is a Dicot Fireweed, Epilobium

Dicot Flowers In this penstemon, the petals are fused into a tube You can still determine that it has 5 petals however by looking at the number of flower lobes Notice the nectar guides, lines that point toward the center of the flower

Dicot Flowers Notice that these flowers also have a fused petal tube, and you can distinguish 5 lobes Also note the nectar guides in this flower This is another Dicot Yellow monkeyflower, Mimulus guttatus

Flowers That Break the Rules Many flowers “break the rules”—learning to be observant will help you know plants better In skunk cabbage and some other plants, the colorful part is a spathe and the flowers themselves are very small and located on the whitish spikes

Flowers That Break the rules In dogwoods, what appear to be petals are actually modified and colorful leaves called bracts The many flowers are in clusters in the center of the bracts

Flowers That Break the Rules Some flower form tight clusters such as this wild carrot Each structure has many flowers, and each of these can bear seeds This kind of flat-top structure is called an umbel-umbel plants often attract butterflies

Flowers That Break the Rules All plants of the sunflower family form flowering structures called flowering heads It looks like one large flower but instead is many tiny ones grouped together Each “petal” is a separate flower for example

Flowers That Break the rules This is another member of the sunflower family Notice the tiny circular ring of flowers in the flowering head in the lower right Each of the tiny flowers in this ring is blooming and each will produce a single seed

The Sexual Parts Although petals and sepals can be attractive, the real work of the flower occurs in the sexual parts Stamens bear the pollen Pistils bear the ovules that become seeds when fertilized Erythronium flower with pendulous stamens and pistils

The Sexual Parts Look carefully at the central part of this flower Look for 6 stamens and 1 central pistil The pistil ends with a pink stigma split three ways The stigma is usually sticky and will hold pollen delivered by a pollinator, in this case probably a bee A cat’s ear, Calochortus species

The Sexual Parts In this flower, note the 5 stamens and central pistil Flannelbush, Fremontodendron californicum

The Sexual Parts This flower has numerous stigmas ready to release their pollen In the center is one pistil with the stigma divided into many parts Camelia sasanqua

Fertilization Once pollination occurs, the pollen grain begins to grow and sends a tube down through the pistil This leads to fertilization and the production of seeds A species of wild rose, Rosa sp.

Fruits and Seeds Seeds of flowering plants are carried in some kind of fruit structure This Asian pear is a kind of fruit called a pome and the seeds are inside Seeds are disseminated by foraging animals and the seeds pass through the digestive system

Fruits and Seeds Seeds of this wild plant called a baneberry are most likely disseminated by birds The seeds are toxic, but since birds do not chew, the seeds pass unharmed through the bird’s digestive tract Actea rubra

Fruits and Seeds Seeds of these lupines are carried in pods Pods open along lines to release the seeds when they are ready The red flowers are another species, Mimulus cardinalis Lupinus polyphyllus

Fruits and Seeds Seeds of milkweeds have white parachute like attachments These are disseminated by wind

Fruits and Seeds This is cow parsnip which has flowers in the umbel form This flat-topped structure persists in seed formation This is one of the plants that also supports the growth of butterflies

Fruits and Seeds Beechnut produces seeds that are nuts The nuts are carried within an outer structure that splits open at maturity and releases the seeds to the soil below They may also be carried by animals to new locations

Fruits and Seeds This pod has opened to reveal the seeds inside Each seed is capable of producing a new plant which grows from a tiny embryo inside Peony seeds

Seed Germination Under suitable conditions seeds germinate into new plants and the cycle starts anew Clip art

This is the End This is the end of our brief beginning tour of botany for gardeners We have only touched the surface and there is much more to discover and know I wish you luck on this journey Echinacea purpurea ‘White Swam’

Botany Primer for Gardeners Created by Linda McMahan, Botanist and Community Horticulture Faculty, Oregon State University Extension Service in 2010 All photographs except as noted are those of the author. This presentation and included materials may be freely used for educational purposes. For other uses, please contact the author at linda.mcmahan@oregonstate.edu

Botany Primer For Gardeners

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