Ulmaceae (elm family)

Question 1

What family is Ulmaceae?

Answer 1

Elm family

Question 2

Key features:

Answer 2

• leaves w oblique bases, pinnate venation, singly or double serrated margin
• fruit w evenly winged, disk samara OR drupe
• woody trees or shrubs w alternate leaf arrangement

Question 3

How many elm species can be found in MN? Which is non-native?

Answer 3

5, non-native is Siberian elm

Question 4

How many Native American elms (Ulmus americana) have died since Dutch Elm disease arrived in the state in 1961?

Answer 4

More than 90%

Question 5

What was the problem for having some municipalities having up to 100% of their forest canopy being American elm?

Answer 5

Dutch elm disease took em the fuck out (resulted in urban desert!)

Question 6

What are the problem(s) with Siberian elm (Ulmus pumila)?

Answer 6

• Will not persist in shady understory
• mainly a nuisance species in open fields, city/suburban lots,

Question 7

Which elm produces the hardest, heaviest, densest wood of the elms?

Answer 7

Rock elm (Ulmus thomasii)

Question 8

Which elm has/had a medicinal use? What is it?

Answer 8

Red elm (Ulmus rubra), soothing coating over mucus membrane

Question 9

Short history of the spread of the Dutch elm disease (Ophiostoma ulmi)?

Answer 9

• first discovered in Netherlands in 1921
• then in the US in Ohio in 1930
• then MN in St. Paul and Monticello in 1961
• has since killed over half the elm trees in Northern U.S.

Question 10

How does Dutch elm disease spread?

Answer 10

-infections can occur via root grafts with infected trees (fastest disease progression/death)(large trees within 20 feet = almost 100% of root grafts
- 3 species of bark beetle (European elm bark beetle, Banded elm bark beetle, Native elm bark beetle)
- beetles carry fungal spores into the wood as they feed, spores germinate and produce mycelium that grow into the xylem tissue. Fungus then produces toxins that induce the tree to produce plugs in the xylem, SO plugs, mycellium, and plant gums block xylem vessels causing wilting and death

Question 11

Which elm bark beetles result in faster spread of Dutch elm disease? Native one or exotic ones?

Answer 11

Native elm bark beetle (Hylurgopinus rufipes)

Question 12

Is there any hope for American elm?

Question 13

What’s the bacterial pathogen that impacts elms?

Answer 13

Wetwood (Erwinia mimipressuralis)

Question 14

Whats the story with hackberry nipple gall psyllid?

Answer 14

• Pest lays eggs under a leaf and the larvae hatch and feed on leaf, Leaf reacts by forming an outgrowth around the larvae (no apparent damage to tree?)

Question 15

What does witches brew fungus do to hackberry trees?

Answer 15

Infection results in a hormonal change that causes a proliferation of shoots to emerge from branch ends

Question 16

Celtis (Hackberries) USED to be ulmaceae but are now cannabaceae

Question 17

Uses

Answer 17

• lumber (wagon wheels, wooden autobodies, ship building)