Herself's Houston Garden

Conservation through cultivation

Plant classifications and how to use them




Classifying plants into

Families->Genus->Species->Subspecies/Varieties->Cultivar->Hybrid

makes it much easier to figure out what each plant wants and needs. If you can’t find information on the exact plant you have you can look for other closely related plants.

Family names end in -aceae and plants share many botanical features ( Wiki Plant Families )

Genus share structural characteristics names usually come from literature

Species is the place a plant is from originally, discoverer or plants appearance

Varieties are naturally occurring changes in species

Cultivars are naturally occurring varieties that need human intervention to reproduce such as cloning

Hybrids are human created varieties.

Plants are classified into three main groupings: nonvascular, vascular seedless, and vascular with seeds.

Non-vascular plants are the first ones to have left the oceans about 450 million years ago. They are the division of Bryophyta which includes the three classes: Musci, Hepaticae, and Anthocerotae. These plants can not stray far from water because they have no vascular system to carry the water to far reaches of the plant.

Bryophyta Musci has over 6000 species of mosses in it, mostly tropical.
Bryophyta Hepaticae are your liverworts which has about 8500 species.
Bryophyta Anthocerotae contains about 400 hornworts.

Vascular seedless plants began to appear about 430 million years ago. They include the divisions of Polypodiophyta, Psilophyta, Sphenophyta, and Lycophyta.

Polypodiophyta contains about 12000 species of ferns.
Psilophyta contains just a few species of whisk (rootless/leafless) ferns.
Spehophyta contains your horsetail type plants, only about 40 species remain.
Lychphyta are your club mosses of which we have about 1000 species.

Vascular seed plants were the last to evolve. They include the divisions of Pinophyta, Cycadophyta, Ginkgophyta, Gnetophyta, and Magnoliophyta.

Pineophyta are your conifers or cone bearing plants, 550 species remain.
Cycadophyta are your cycads only 100 species exist, mostly tropical.
Ginkgophyta has only one surviving plant, Ginkgo biloba.
Gnetophyta has 100 species of mostly desert plants.
Magnoliophyta contains all the flowering plants, it contains the most species at about 400,000.

Magnoliophyta contains two classes: Magnoliopsida [dicots]( seedlings sprout with two leaves and complex vein patterns) and Liliopsida [monocots] ( seedlings sprout with one leaf which has parallel veins ).

There are over 170,000 species in the magnoliopsida class.
The liliopsida contains about 60,000 species of plants.

Magnoliopsida contains six subclasses: Asteridae, Caryophyllidae, Dilleniidae, Hamamelididae, Magnoliidae, Rosidae.

Liliopsida contains five subclasses: Alismatidae, Arecidae, Commelinidae, Lilidae and Zingiberidae.

The USE Natural Resources Website has a nice tree of all the plant kingdom on down to species. If you are having trouble finding care information for a plant, try searching down that tree and see if you can find a closely related plant.

You’ll also want to check out their Searchable image gallery if you are having trouble figuring out what a plant might be.

Other taxonomy sources:
Tropicos
Integrated Taxonomic Information System
USDA Plants
The International Plant Names Index
Kew: Data and publications