Agriscience 102
Applied Agricultural Science and Technology
8390
Class Notes Key
Plant Recognition: Classification and Identification of Field Crop Plants
TEKS: 119.13 (c)(3)(D)
Many classification systems exist to group plants for identification purposes. Field crops are those
plants grown for food, feed, fiber, and/or industrial purposes. These types of plants are classified
according to their use, season of growth, life span, and botanical characteristics.
CLASSIFICATION OF FIELD CROPS ACCORDING TO USE
Cereal crops include those grown to furnish edible food and feeds. These crops, which are members of
the grass family, include corn, wheat, oats, and rice.
Legume crops are grown mostly for their edible seeds, which have a high protein and oil content. These
types of crops include:

soybeans

peanuts

field beans

garden peas

lentils

cowpeas
Forage crops include grasses and legumes grown as feed for animals. Forage crops for feeding purposes
are used in the form of silage, hay, and fodder.
Grass forages include:

corn

sorghum

oats

barley

pasture grasses
Alfalfa and clover are examples of legume forages.
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Root crops are those grown for their edible roots, which also have a high starch content. Crops
classified as root crops include:

sweet potatoes

carrots

rutabagas

beets

turnips
Cotton is an example of a fiber crop. The textile industry uses its fibrous bolls to produce clothing, rope,
twine, and other products.
Sugar crops provide a raw source for sugar products. These crops include:

sugar beets

sugarcane

sweet sorghum

corn
Oilseed crops such as sunflowers, soybeans, and canola are important for their high oil content.
Tuber crops, similar to root crops, also have a high starch content. Stimulant crops include those such as
tobacco, coffee, and tea.
Food crops include fruit and vegetable crops. These crops supply humankind with valuable vitamins,
nutrients, and fiber.
Examples of fruit crops include:
apples
pear
peaches
citrus
plums
(and others)
Examples of vegetable crops are:
potatoes
onions
tomatoes
cabbage
sweet corn
(and others)
lettuce
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Timber crops, which supply materials for industrial and construction purposes, include pine trees and
many varieties of hardwood trees.
CLASSIFICATION OF FIELD CROPS ACCORDING TO SPECIAL USES
Green-manure crops, such as clover and soybeans, are those which, when plowed under the soil during
their latter growing stages, supply nutrients and organic matter to improve the soil quality. Cover crops
are those planted to protect the soil surface against wind, water erosion, and the loss of soil nutrients.
Emergency or catch crops include quick-growing crops such as rye and sudangrass that are planted to
replace other crops that have failed.
Green-chop crops are those that are cut green and fed, uncured, to livestock. Similarly, silage crops
include those, for animal feeding purposes, that are harvested and allowed to pass through states of
partial fermentation.
Peas and clover are two types of companion crops that are grown to aid in the establishment and growth
of other crops.
CLASSIFICATION OF FIELD CROPS ACCORDING TO SEASON OF GROWTH
In the United States, two distinctive seasons for field crop growth are:

warm season

cool season
Warm season crops are grown during the spring and summer and are not adapted to cooler temperatures.
Warm season crops include:

cotton

tobacco

field peas

sorghum
Cool season crops require cool temperatures for optimal growth. Cool season crops include:
wheat
potatoes
oats
rye
barley
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CLASSIFICATION OF FIELD CROPS ACCORDING TO LIFE SPAN
Annuals include field crops such as corn, peas, and sorghum that complete their life cycle (from seed to
seed) in one growing season.
Biennials, such as cabbage, beets, and carrots, complete their life cycle in two growing seasons. During
the first season the plants produce vegetative parts and store food. In the second season, the plants
produce flowers and seeds.
Perennials grow for more than two growing seasons.
THE BINOMIAL CLASSIFICATION SYSTEM OF NAMING PLANTS
Taxonomy is the science of classifying and naming plants.
To prevent confusion and false
identification, plant scientists use botanical names to identify plants universally.
Carl Linnaeus, a Swedish botanist, developed the binomial classification system for naming plants.
The scientific name used to identify plants usually consists of three parts:

genus name

species name

cultivar name
THE PLANT KINGDOM
The plant kingdom is subdivided into four phyla:

Thallophytes

Bryophytes

Pteridophytes

Spermatophytes
Thallophytes include algae, fungi, and bacteria. They have no stems, roots, or leaves.
Bryophytes are non-flowering plants that have no roots. Many also have no stems or leaves. Mosses
and liverworts are examples of plants in this phylum.
Pteridophytes include vascular plants, such as ferns, that have roots, stems, and leaves but lack flowers
or seeds.
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Spermatophytes include highly developed plants that produce seeds or fruit after fertilization takes place
in the flowers. This phylum of plants includes the two subphyla:


Gymnosperms
Angiosperms
Gymnosperms produce “naked seeds” that are not enclosed in ovaries. Examples of plants in this
subphylum include:



pines
junipers
spruce
Angiosperms include flowering plants that produce seeds enclosed in ovaries. Two subdivisions or
classes of this subphylum are:


monocotyledons (monocots)
dicotyledons (dicots)
Monocots have a seed embryo with a single cotyledon. Flower parts in these plants are in multiples of
three. Plants in this class also have a(n) parallel leaf venation pattern, and a(n) asymmetrical vascular
system with scattered vascular bundles. The root systems of plants in this class are mostly fibrous
and/or adventitious.
Dicots have a seed embryo with a two cotyledons. Flower parts in these plants are in multiples of four
or five. Leaf venation patterns of plants in this class are net-veined. The vascular system of plants in
this class is symmetrical and arranged in a(n) circular pattern within the stems. Most plants in this class
also have a tap root system.
Plant families of monocotyledons include the:


grass family (Poaceae)
lily family (Liliaceae)
Plant families of dicotyledons include the:






legume family (Fabaceae)
nightshade family (Solanaceae)
mustard family (Brassicaceae)
morning glory family (Convolvulaceae)
mallow family (Malvaceae)
rose family (Roseaceae)
Each family of plants is further subdivided into genus, species, and cultivars.
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