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Species List 5 (web, ppt)

ANGIOSPERMAE

FABACEAE: Pea family

Family key feature: fruit a legume

• very large family (15,000 species)
• trees, shrubs, herbs occupying tropical to arctic environments
• Possibly best known to us for agricultural or ornamental uses-- alfalfa, peas, beans (more than you can think of), peanuts; high in protein content because many can fix nitrogen-- essential component of protein (amino acids)
• few tree species in US, most are subtropical

Genera: Gleditsia and Robinia

Genus key features	bark	leaves/twigs	flowers/inflorescence
Robinia	ropey	pinnately compound, stipular thorns	racemes of sweet-pea like flowers
Gleditsia	flat ridges	bipinnately compound, thorns from branched short shoots

Gleditsia triacanthos
Robinia pseudoacacia

 

PLATANACEAE-- Sycamore or Planetree Family

small family with 1 genus and few species

Family key feature-- alternate palmately lobed leaves, fruit-- heads of achenes

Genus Platanus-- Sycamore or Planetree

Platanus x acerifolia is a hybrid between European and American species, which arose in a botanical garden in England (London Plane tree)

Leaves: alternate, palmately lobed, 3-lobes

Fruit: 1-2 heads of achenes per stalk

widely planted as a street tree, north entrance to UW campus lined by P. x acerifolia in honor of student who died in 1st World War

ULMACEACE-- Elm Family

small family with only one important genus in US

Family key feature: no family level diagnostic

Genus Ulmus: Elm

Genus key features:

Fruit	Leaves
samara-- wing completely encircles the seed	elliptical, doubly serrate with asymmetrical base

Ulmus americana-- widely planted as a street tree-- nearly eliminated by Dutch elm disease, an exotic disease (fungus clogs vessels) to which N. American species are not resistant

ERICACEAE: Heath Family

Very large family-- most are shrubs, many in harsh environments

Family key feature: no uniform feature (usually small, fused, bell-shaped corolla)

Examples-- blueberries, cranberries, huckleberries, rhododendrons, azalias

Genus Arbutus

Arbutus menziesii--

Leaves: 1 yr.-persistent, oval-elliptical. Flowers in panicles

Bark: exfoliating (allelochemic properties)-- inner bark is green, outer bark is red-- shed during fall

Botanists on Vancouver’s ship thought Arbutus was Magnolia-- hence Magnolia bluffs and neighborhood of Magnolia

 

HIPPOCASTANACEAE—Horse chestnut family

Small family: Several shrub species in North America

Family key features:

Leaves:	Inflorescence:	Fruit:
opposite, palmately compound	showy panicles	capsule with large brown seed (seed looks like chestnut seed)

 

Genus Aesculus: buckeye or horse chestnut

Genus key feature: family diagnostic applies to genus

few species in North America (Buckeye)

Aesculus hippocastanum Horse chestnut

native of Balkan countries, planted widely as an ornamental

• large showy, white panicles
• 7-9 leaflets, oblanceolate with doubly serrate leaf margins

 

LAURACEAE: Laurel Family

Diverse family mainly in tropics and subtropics-- 45 genera, 2200 species

Family key feature:

• strong aromatic compounds in leaves, stems, roots
• fruit a one-seeded berry or drupe

Contains plants familiar to us-- bay leaves, camphor, cinnamon, avacado

Genera: Umbellularia and Sassafras

Genus key features	Leaves	Tree Form
Umbellularia	entire, persistent	deliquescent
Sassafras	entire, polymorphic- elliptical, mitten shaped, 3-lobed deciduous	excurrent

Umbellularia californica
Sassafras albidum

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