1- Botany: History and Classification

A. What is Botany?

Botany is the organized study of photosynthetic organisms.

Definitions

Botane (Greek): herb/grazing

Boskein: to feed

Botanicus: plant

Phyto: plant

Botany can also be referred as phytology.

Where did botanical study begin?

Before recorded history: 60,000 years ago in Shanidar, Iraq.

  • Early examples of plant use:

    • Medicines and Dyes → during the Neanderthal era

      • Medicine: goes back 4,000 years ago. Documents recorded in herbals (medical text/documents about plants and how they are used to treat conditions)

    • In Asia (China, India, Egypt) → records of plant use well before Europe did

  • As a formal science:

    • Renaissance: Universities initiated collections of known plants and gardens

    • In the 1700’s, it was established as an academic discipline for the first time

  • Founder of Botany: Theophrastus (287 BC), who referenced plants in medicinal terms

There are about 400,000+ extant species, with thousands of extinct species.

How are plants grouped together? What are the major groups?

Major groups:

  • Systemics: evolutionary relationships between plants

  • Taxonomy: naming and organization

B. Plant Classification

Latin Polynomials--long descriptive names

  • These names are based on physical features of plants. Ex: size, shape, color, organs, leaves, habitat, etc.

  • But these names are long, inconsistent, and difficult to decipher.

Carl Linnaeus (1707-1778)

  • Linnaeus was a Swedish physician/botanist. He created the Genus concept → all plants are placed into groups based on similar characteristics.

  • He popularized the use of binomial nomenclature and wrote Species Plantarium.

  • A few other scientists before him wrote papers about nomenclature but he was the first recognized.

Binomial: two names

  • Examples of binomial: Glycine max or Glycine max

  • Senna obtusifolia L. = a common weed in the Southeastern United States

    • Senna: genus. Obtusifolia= species. L.= Authority (first person who gave scientific name)

    • The entire name Senna obtusifolia L. is the species/the entire scientific name.

Ranks

How to identify ranks:

  • -ophyta: Phylum

  • -opsida: Class

  • -ales: Order

  • -aceae: Family

Genus and specific epithet are ALWAYS italicized! Authority is NOT italicized. Genus may be abbreviated.

  • Ex: D. muscipula Ellis.

International Code of Nomenclature for Algae, Fungi, and Plants (ICN)

  • A highly modified from Linnaeus

  • International Botanical Congress (IBC) meets every 6 years to vote on changes to nomenclatural rules and classification.

    • They met last in 2017 in Shenzen, China → now we operate under “Shenzen code”

    • Next they will meet in 2024 in Madrid, Spain

ANGIOSPERMS (Phylum Level)

  • About 350,000+ species of flowering plants (where a fruit encloses a seed)

  • Angiosperms are the most diverse group of extant plants with >300 families

    • Angio-: vessel

    • -sperm: seed

Monocots (Class level)

  • Liliopsidia

  • Cotyledon → seed structure

Example families and NC or crop plants within this group:

  • Poaceae (Grass family)

    • sugar cane

    • corn

    • turf

    • wheat

    • rice

    • oats

  • Liliaceae

    • lily

    • tulips

    • hyacinth

    • onions

    • garlic

  • Araceae (Palm family)

    • oil palm

    • coconut palm

Dicots (Class level)

  • Dicots: two cotyledons

Examples families and NC or crop plants:

  • Solonaceae

    • Nightshade

    • potoato

    • tobacco

    • eggplant

    • peppers

    • tomato

    • petunia

  • Rosaceae:

    • strawberry

    • apple

    • peach

    • plum

    • pear

    • cherry

  • Fabaceae:

    • soybean

    • greenbean

    • peanut

    • alfalfa

    • clover

Some angiosperms are globally important food sources.

Six plants account for 80% of the world’s calorie supply (unranked):

  1. Corn

  2. Rice

  3. Wheat

  4. Potato

  5. Cassava

  6. Sweet Potato

Other important food plants:

  • Oat

  • Coconut

  • Barely

  • Sugarcane

  • Sugar Beet

  • Common Bean

  • Sorghum

  • Soybean

  • Banana

  • Pineapple

  • Peanut

  • Sunflower

Some are important sources of oils.

  • Coconut

  • Olve

  • Canola

  • Sunflower

  • Avocado

  • Peanut

  • Corn

  • Soybean

Many are poisonous or have parts that are poisonous, including the following:

  • Poison ivy

  • Belladonna

  • Castor bean → produces ricin and castor oil

  • Oleander

  • Poison hemlock

  • Cow parsnip

  • Nightshade

  • Cherry pit

Some are weeds.

Cocklebur, morning glory, Johnson grass, crabgrass, kudzu, sicklepod, pigweed, and so on.

Why are these plants problematic?

  • They grow fast. They outcompete other plants for light, mineral absorption, and water.

GYMNOSPERMS (not a monophyletic group, multiple phyta instead)

Conifers--Phylum Pinophyta

  • Cone-bearing plants (ex: pine, cedar, seqoia, yew, fraser fir, juniper

Cycads--Phylum Cycadophyta

  • Most rare, usually toxic, tropical/subtropical

Gingko biloba--Phylum Ginkgophyta

  • Only living member of phylum, have conductive tissues for water/minerals

SEED-FREE VASCULAR PLANTS

  • Ferns, Whisk Ferns, Horsetails, and Lycopods

  • Plants with vascular tissues for water and nutrient conduction that reproduce by spores instead of seeds.

  • Almost all are terrestrial.

  • Two phyla.

BRYOPHYTES (Bryon = moss)

  • Mosses, Hornworts, and Liverworts

  • Most anicent of the land plants.

  • Plants without vascular tissues that reproduce by spores instead of seeds. Semi-aquatic to terrestrial. Small size relative to other land plants.

  • Three phyla.

GREEN ALGAE

  • Nonvascular, aquatic organisms. Two phyla under Kingdom Plantae.

We will also discuss other photosynthetic organisms not in Kingdom Plantae that are also significant.

  • Cyanobacteria (blue-green bacteria, Domain Bacteria, Phylum Eubacteria)

  • Algae classified under Kingdom Protista, including brown algae, red algae, diatoma, and dinoflagellates.

C. Plant Preservation

Herbarium (pl. herbaria: Locations where collected specimens are preserved, catalogued, organized, and stored.

Index Herbarium

  • Complete list of herbaria worldwide

  • About 3,400 of them worldwide

    • Major effort to make them searchable

Herbaria function as:

  1. Research centers → house voucher “type” specimens for species

  2. Teaching resources

  3. Extension refernces → Plant ID

Types of plant specimen preservation

  1. Press specimen in plant press, dry them so they don’t mold, mount on herbarium sheet with label

  2. Chemical fixation (by alchohol or formaldehyde)

  3. Dessication using sand/borax to preserve in 3D

  4. Encasing in plastic/resin → seems good but takes up a lot of space

In order to put a new plant into the botanical record, one must:

  1. have a proper description of the plant published and circulated

  2. name that conforms to ICN

  3. obtain and preserve a voucher specimen that serves as the “type” for that species

D. Some Common General Plant Descriptions

Origins:

Native flora → evolved in the location its found in

Non-native flora: did not evolve in the location it’s found in (introduced/exotic)

  • Invasive: non-native flora that outcomplete native flora, reproduces quickly, and a limited number of natural predators/competitors