Plant Anatomy and Physiology

Just the Concepts

PLANT CLASSIFICATION

Objectives

• Explain systems used to classify plants;• Compare and contrast the hierarchical classification of

agricultural plants; and • Classify plants according to life cycles, plant use, and

status as monocot or dicot.

Classification Systems

• What are some ways that we could classify plants?• • • • •

Classification Systems

• Taxonomy: the science of classification• To classify into ordered categories

Classification Systems

• Why Classify?• Carolus Linnaeus (1707-1778)• Swedish botanist / physician that

collected plants for their curative properties needed to organize his collection.

• Contributed to the development of our modern system of taxonomy.

• Developed binomial nomenclature, a two-word naming system still used today. Carl

Classification Systems

• Botanical Classification• D K P C O F G S• Domain• Kingdom• Phylum• Class• Order• Family• Genus• Species

Classification Systems

Classification Systems

• Mode of Reproduction• Sexual• Develop from a seed or spore after the union of male and

female gametes• Gametes: Sex cells

• Asexual• Reproduce by vegetative means without sexual gametes

Classification Systems

• Mode of Pollination• Naturally self-pollinated• Pollen and embryo sac are produced in the same floral

structure or different flowers on the same plant• Naturally cross-pollinated• Pollen transferred from one flower to another flower of a

different plant• Both self- and cross-pollinated• Largely self-pollinated, but a some cross-pollination will occur

Classification Systems

• Life Cycle• Annual• Plants germinate, grow, flower, produce seed, and die all in one

season• Biennial• Requires two growing seasons to complete its life cycle• The first accumulating food reserves; the second producing

reproductive parts• Perennial• Plant that lives indefinitely; produces seeds year after year

Classification Systems

• Growth Habit• Herbs• Succulent plants with self-supporting stems

• Vines• Herbaceous climbing, or twining plants without self-supporting stems

• Lianas• Woody climbing or twining plants that require other plants for vertical support

• Shrubs• Small tree-like plants generally less than 15 feet tall; produce several trunks

from the base• Trees• Plants with continuous growth and a large development of woody tissue; single,

distinct stem; more than 15 feet tall

Classification Systems

• Leaf Retention• Evergreen• Maintain their leaves throughout the year

• Deciduous• Naturally shed their leaves annually for extended periods

Classification Systems

• Ecological Adaptation or Habitat• Epiphyte

• Grow above ground on another plant for vertical support; not a parasite• Halophyte

• Can grow in high salt conditions• Hydrophyte (Aquatic)

• Grow in water or in waterlogged soil• Lithophyte

• Grow in rocks or rocky terrain• Mesophyte

• Adapted to growing in moderate conditions (most of the plants that we know)• Parasite

• Grows on another plant and takes its nourishment from that plant• Saprophyte

• Grow in decaying matter and have no green tissue• Sciophyte

• Adapted to low light conditions• Terrestrial

• Grows on land with roots under ground absorbing water and a shoot above ground (most of the plants that we know

• Xerophyte• Adapted to grow in areas with little or no water

Classification Systems

• Flowering vs. Non-Flowering• Flowering plants produce seeds

• Seed Parts (Cotyledons)• Monocot• Dicot

Classification Systems

• Monocot• Embryo with one Cotyledon• Pollen with one furrow or pore• Flower parts in multiples of three• Major leaf veins are parallel• Vascular bundles are scattered in the stem• Roots are adventitious

• Dicot• Embryo with two cotyledons• Pollen with three furrows or pores• Flower parts in multiples of four or five• Major leaf veins are netted• Vascular bindles are a ring in the stem• Roots develop from a radicle

Agricultural Classification

• Crops vs. Weeds• Crop• A useful plant grown for a specific purpose• Used by humans directly or indirectly, raw or processed• Intentionally grown and managed

• Weed• Any plant growing where it is not wanted• Competes with the intended plant for space, light, nutrients,

and water

Agricultural Classification

• Agronomic Crops vs. Horticultural Crops• Agronomic (Field Crops)• Mostly annual, herbaceous plants grown under extensive or

large-scale culture• Usually dried and processed prior to use

• Horticulture crops• Annual and perennial plants grown under intensive culture• Intensive: large input of capitol, labor, and technology per acre

• High moisture content, spoil quickly• Used for food, medicine, beauty

Agricultural Classification

• Could some plants be classified in several groups?

• Which ones?

Agricultural Classification

• We have got to have some order• We base most classifications on Primary Use rather than

on the other minor uses

Agricultural Classification

Food Crops

Non-Food Crops

Staple Crops

Grain Crops

Legume Seed Crops

Root & Tuber Crops

Oil Seed Crops

Sugar Crops

Beverage Crops

Rubber Crops

Latex & Gum Crops

Dye & Tannin Crops

Fiber Crops

Pasture & Forage Crops

Biofuel Crops

Olericulture Crops

Spice Crops

Essential Oil Crops

Ornamental Crops

Biocidal CropsIndustrial Crops

Plantation Crops