Cache Creek Dichotomous Key transcript

Introduction — identify plants from Cache Creek:

A dichotomous key helps you identify an object by choosing between two pieces of information. Use a botanical dichotomous key in this activity to learn the scientific names of eight plant species found near Cache Creek, British Columbia. Correctly name all of the species, and you’ll get a Junior Taxonomist certificate that you can print out and display.

Dichotomous Key:

Use this key to identify the depicted species:

1a.) Evergreen needles: Pinus ponderosa
1b.) Leaves may be very small or absent, if evergreen, not needlelike: Go to 2a

2a.) Leaves forming a distinct sheath around the stem: Go to 3a
2b.) Leaves with no apparent sheath: Go to 4a

3a.) Flowers large and showy: Calochortus macrocarpus
3b.) Flowers are very small florets: Koeleria macrantha

4a.) Flowers pink to rose-purple or white, but never yellow: Go to 5a
4b.) Flowers yellow: Go to 7a

5a.) Leaves palmate (hand-shaped): Geranium viscossimum
5b.) Leaves long and slender: Go to 6a

6a.) Leaves arranged in a basal cluster: Lewisia rediviva
6b.) Leaves not basal: Chamerion angustifolium

7a.) Dark green stems are spiny and succulent: Opuntia fragilis
7b.) Stems are not spiny or succulent: Artemisia tridentata

Species descriptions:

Geranium viscossimum
This species' flower has five pinkish-lavender petals that are deeply veined. Its non-sheathing leaves are extended on stalks and are deeply palmately lobed. The stems and leaves are covered with sticky, glandular trichomes.

Opuntia fragilis
Brittle prickly-pear cactus has jointed, dark green succulent stems with protruding barbed spines. The large flowers are yellow when mature and have many stamens.

Lewisia rediviva
Bitterroot has flowering stalks that arise from thick, branched taproots and grow close to the ground. The non-sheathing, basal leaves are long, slender and round in cross-section. The flowers are pink or white with approximately 15 petals and 6 to 9 sepals.

Calochortus macrocarpus
Sagebrush mariposa lily is a monocot as opposed to a dicot. Only one other species used in this dichotomous key is a monocot. Some monocots, such as this one, have leaves that tend to sheath along the stem. The non-basal leaves are long and slender.

Pinus ponderosa
This species is a large conifer, standing 15 to 30m tall. The bark is distinctive as it resembles puzzle pieces piled on top of each other. The leaves are evergreen needles occurring in bundles of three.

Koeleria macrantha
Junegrass is in the grass family. This monocot has dense, spike-like panicles with 2-4 florets protruding from short branches. The florets of this grass do not have awns, like many other species in this family. Species in the grass family have jointed stems that are round in cross-section and hollow. The leaves tend to sheath along the stem then emerge as long, skinny leaf blades.

Artemisia tridentata
Big sagebrush is an evergreen shrub that is approximately 2m tall. The leaves are 1-3cm long with 3 teeth at the tip. Both the adaxial and abaxial surfaces of the leaves are covered with dense, greyish hairs. The flowers are small and yellow. Its stems are neither spiny nor succulent.

Chamerion angustifolium
The flowers of fireweed are rosy-pink and form an elongate inflorescence on top of an unbranched stem. The non-sheathing, slender, lance-shaped leaves are arranged in an alternate pattern along the stem.

Glossary of terms:

abaxial: lower side of the leaf

adaxial: upper side of the leaf

awns: either hair- or bristle-like appendages that extend from the florets of many grasses

basal: all leaves diverge from the base of the plant stem

carpel: a carpel is made up of a stigma, a style, and an ovary, which is the female reproductive organ of a flower

conifer: a conifer is a cone bearing plant. Conifers are usually evergreen with needle-shaped or scale-like leaves

dicot: A dicot is a type of flowering plant that has 2 cotyledons (seed leaves) which are usually only visible immediately following germination of the seeds. Dicots generally are distinguished by having their parts in multiples of four or fives; for example, five petals, five sepals, five carpels and five stamens.

evergreen: An evergreen plant is a plant that retains its leaves year-round, with each leaf persisting for more than 12 months. This contrasts with deciduous trees, which completely lose all their foliage for part of the year.

florets: a floret is a small individual flower in a flower head

inflorescence: a cluster of flowers or a flower head on a plant

lance: a lance shaped leaf is long and pointed like a sword

monocot: A monocot is a type of flowering plant that has a single cotyledon (seed leaf). The cotyledon is usually only visible immediately following germination of the seed. Monocots are generally distinguished by having their parts in multiples of three; for example, three petals, three sepals, three carpels and six stamens.

palmately lobed: with leaf segments arranged palmately (hand-like)

panicles: a panicle is a branched stalk on which flowers are borne on the secondary branches

sepals: Sepals are leaf-like structures located below the petals of a flower; collectively, the sepals form the calyx. They often enclose the developing flower and later may protect the developing seed or fruit.

sheath: a sheath is the part of the leaf that wraps around the stem – primarily in grasses and other monocots

spike: a spike is an elongated, unbranched stalk on which stalkless flowers are borne

spine: a strong, sharp-pointed, usually woody outgrowth from a stem or leaf

stamen: a stamen is the male reproductive structure of a flower consisting of the anthers (pollen sacs) and a slender filament

succulent: a succulent plant has tissue (usually stems or leaves) that are adapted to water storage

trichomes: trichomes are plant hairs or extensions from the epidermis of the plant that may provide shade and protection for the plant

Image labels (defined visually):

anther
auricle
collar
culm
filament
leaf blade
ligule
ovary
petal
receptacle
simple carpel
stigma
style
unfused compound carpel

Certificate:

John Davidson Botanical Society

This certifies that [Enter your name here] has successfully completed the Dichotomous Key of Cache Creek and learned how to identify plant species of the Cache Creek area thus having shown proficiency in the science of botany is hereby awarded the title of Junior Taxonomist.

John Davidson
President