Life Zones: Equator – Tropical

In the Zone

The Rocky Mountains, due to their altitude, are not hospitable to Tropical plants, so this presentation has slides of plants in the Tropical Zone that are ubiquitous in the Rocky Mountain states and show up in nearly every zone.



Lantana is a beautiful sun-loving plant that thrives in full sun. Its flowers range from shades of yellow, red, pink, purple and white. Its wide dark green foliage helps to create a lovely contrast to the cluster of colorful flowers. There are both upright and trailing varieties of Lantana.

Native to Central and South America, the flower has become fully adapted as a perennial evergreen in the Tropic Zone. It cannot tolerate frost, so it is mostly found in truly equator-like climates.


Thistles of some sort are found in all of the Life Zones of the Rockies and below. They appear in every state in our country and around North America. Above Timberline they take on grotesque shapes.

The Buffalo Bur is a dangerous weed thistle that is covered with wickedly sharp, stinging spines all over it. The flowers are usually a bright yellow (about 1″) and have five broad lobes and five beak-like antlers. Four of the antlers are straight and one is curved. The bur starts off as a green colored fruit and resembles a watermelon plant. It is poisonous and dangerous because of glyco-alkaloids solanine and tropane alkaloids in the plant. Even the roots have a way of storing up toxins that are harmful to animals.

The Bull Thistle has a whole woolly top, formed of compressed leaves and inconspicuous flower heads, that bend over to resemble the head and shoulders of some shaggy animal. In spite of the prickles on the stems of the plant and the leaves, I have noticed that horses nip off the flower heads and eat them with relish.

Royal Penstemon

The Royal Penstemon, found along side of the road, is one of about 20 different species of penstemon. They range in color through all shares of lavender, blue, purple and red. They are a member of the Figwort family and have a bloom with two-lipped appearances.Their relation to the garden snapdragon is apparent.



This is a very large genus of plants of the Pea family. They range from the hottest deserts to the high mountain peaks. Some of the species contain poisonous constituents causing animal pain and often death. The locoweed impacts livestock, particularly horses. Loco is the word Crazy in Spanish. Nearly all species of locoweed are colorful when they bloom.


Wild Rose

Wild roses are widely distributed in the Northern Hemisphere. The flowers can be very fragrant and they have bright pink flowers in varying shades: sometimes white, sometimes red. The petals are always surrounded by large clusters of yellow stamens.


The fruit of the wild rose, shaped like small apples (rose hips), turns a deep red color late in the season and adds beauty to this plant during autumn months.