Giraffe Browsing On Spiny South African Acacia The seeds are carried by ants to their nest where the elaiosomes are eaten and the seeds are discarded.Ĭentral American Thorn Acacias With Symbiotic Ants verticillata) are actually lipid-rich structures called elaiosomes. Recent research indicates that the attachment stalks of a related species ( A. This Australian shrub is naturalized in coastal dunes of California and is commonly planted along highways.

The hard black seeds pass through the bird's digestive system unharmed and are dispersed to new locations.

A brightly colored stalk presumably aids in seed dispersal by birds. The enlarged photo insert (red arrow) shows a seed with the attachment stalk uncoiled. cyclopis) showing the bright red attachment stalk coiled around each seed. The above image shows fourteen of these species:ġ. There are nearly 800 species of phyllode and pinnate-leaf acacias worldwide. Another group includes species with fernlike, pinnate leaves divided into small leaflets. One group includes species bearing phyllodes (broadened leaf petioles functioning like leaf blades). The enormous genus Acacia has evolved into two main groups. Swollen thorn acacias of Central America and South Africa form one of nature's most remarkable symbiotic associations with ants. Apparently the exaggerated umbrella-shaped crown enables the trees to capture the maximum amount of sunlight, with the smallest of leaflets. For example, the widespread umbrella thorn ( Acacia tortilis) on vast African savannahs is adapted to this environment. The characteristic flat-topped crowns of some species are genetically determined.

Extensive browsing by giraffes can prune the understory branches of acacia trees. In the wild, native acacias provide the food and habitats for a variety of animals, from hoofed mammals and birds to countless species of insects. Acacias also provide us with many useful products, from beautiful hardwoods to water-soluble gums used as a thickening agent in your favorite frozen dessert. Acacias are commonly cultivated throughout temperate, tropical and desert regions, and include numerous distinctive growth forms with a profusion of yellow or white flower clusters. It is rivaled in size by only a few woody genera, such as Ficus (1,000), Eucalyptus (500) and Cassia (500). In fact, it is one of the largest genera of trees and shrubs in the world, with nearly 800 species. T he genus Acacia is well-represented in southern California parks and gardens with dozens of different species. Modified From: Zoonooz Volume 71 (8): 28-31.Īug. Unforgettable Acacias A Large Genus Of Trees & Shrubs

Plant with soft thorns