Description
The leaves of acacias are compound pinnate in general. In some species, however, more especially in the Australian and Pacific islands species, the leaflets are suppressed, and the leaf-stalks (petioles) become vertically flattened, and serve the purpose of leaves. These are known as phyllodes. The vertical orientation of the phyllodes protects them from intense sunlight, as with their edges towards the sky and earth they do not intercept light so fully as horizontally placed leaves. A few species (such as Acacia glaucoptera) lack leaves or phyllodes altogether, but possess instead cladodes, modified leaf-like photosynthetic stems functioning as leaves.
The small flowers have five very small petals, almost hidden by the long stamens, and are arranged in dense globular or cylindrical clusters; they are yellow or cream-colored in most species, whitish in some, even purple (Acacia purpureapetala) or red (Acacia leprosa Scarlet Blaze). Acacia flowers can be distinguished from those of a large related genus, Albizia, by their stamens which are not joined at the base. Also, unlike individual Mimosa flowers, those of Acacia have more than 10 stamens.
The plants often bear spines, especially those species growing in arid regions. These sometimes represent branches which have become short, hard and pungent, or sometimes leaf-stipules. Acacia armata is the Kangaroo-thorn of Australia and Acacia erioloba is the Camelthorn of Africa.
Acacia seeds can be difficult to germinate. Research has found that immersing the seeds in various temperatures (usually around 80 °C) and manual seed coat chipping can improve yields to approximately 80 percent.
Read more about this topic: Acacia
Famous quotes containing the word description:
“An intentional object is given by a word or a phrase which gives a description under which.”
—Gertrude Elizabeth Margaret Anscombe (b. 1919)
“The type of fig leaf which each culture employs to cover its social taboos offers a twofold description of its morality. It reveals that certain unacknowledged behavior exists and it suggests the form that such behavior takes.”
—Freda Adler (b. 1934)
“It [Egypt] has more wonders in it than any other country in the world and provides more works that defy description than any other place.”
—Herodotus (c. 484–424 B.C.)