AY Honors/Cacti/Answer Key

Investiture Achievement Connection: This Honor is related to the Investiture Achievement requirements for TRAIL COMPANION Nature Study which require (as one of two options) partial completion of Requirement #5 in this Honor. This Honor is a popular choice for the Level 1 Nature Honor required of TRAIL COMPANIONS.

1

Name the chief characteristics of a cactus.

Areoles - Flowers, branches, spines sprout from these- no other plant has this feature.

Spines - Perhaps the most familiar feature of cacti, spines can vary greatly in appearance, shape, size, and color. Spines are not thorns.

Flowers - Flowers are not unique to cacti, but cacti flowers are unique. Cacti flowers are typically quite spectacular and very complex. Unfortunately this field mark is only helpful if the plant happens to be blooming.

Leaves - Most cacti do not have leaves, however, some do. Pay special attention to the presence or absence of leaves.

Origin - All cacti are native to the America's and surrounding islands. With one exception - Rhipsalis baccifera. Although, world wide cultivation has made this less helpful for identification.

2

Name three uses of cacti.

Cacti are used for:

1. Decorating and Landscaping - as houseplants, in dry gardens, or, even as a fence.

2. Edible Fruit Producing - such as Prickly Pear, Hylocereus, Dragon fruit.

3. Psychoactive uses - the Peyote, Lophophora williamsii, is a well-known psychoactive agent used by Native Americans in southwestern United States.

4. Host for bugs - the Opuntia is also used as a host for cochineal bugs for the Cochineal dye industry.

5. Food - Nopal cactus has been a staple food and base for beverages in Mexican culture for centuries.

6. Emergency water source - Some cactus can serve as an emergency water source, but be careful as you can get diarrhea causing further dehydration.

3

In what places are cacti the most plentiful? Why?

Cacti can adapt very well to dry climate or rocky terrain like deserts or mountains, but they can thrive in jungles. They prefer a hot, dry climate, not a humid, hot climate as popular myth suggests. The fact that they also thrive on sandy/rock soil is because the way water doesn’t pool near or on them and the nutrients the soil is rich with.

4

Know and identify from life or pictures 15 species of cacti.

Hey! This is your part. Enjoy!

I took photos of these two. Can you identify them?

Cacti

Davis Mountains

Now go and identify more...

• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 

5

Photograph, observe or sketch at least 10 species of cacti and classify them or grow at least 3 different species of cacti.

There are different tribes of cacti:

• 

  B. hertlingiana (Tribe Browningia)

• 

  Ariocarpus retusus (Tribe Cacteae)

• 

  Calymmanthium (Tribe Calymmantheae)

• 

  Cereus peruvianus (Tribe Cereeae)

• 

  Hylocereus undatus (Tribe Hylocereeae)

• 

  Parodia magnifica (Tribe Notocacteae)

• 

  Golden cereus (Tribe Pachycereeae)

• 

  Schlumbergera gaertneri (Tribe Rhipsalideae)

• 

  D. rhodacantha (Tribe Trichocereeae)

• 

  A. subulata (Tribe Austrocylindropuntieae)

• 

  Cuija (Tribe Opuntieae)

• 

  Pterocactus tuberosus (Tribe Pterocacteae)

• 

  Maihueniopsis subterranea (Tribe Tephrocacteae)