Leaves: Avocado leaves are alternate, glossy, elliptic and dark green with paler veins. They normally remain on the tree for 2 to 3 years. The leaves of West Indian varieties are scentless, while Guatemalan types are rarely anise-scented and have medicinal use. The leaves of Mexican types have a pronounced anise scent when crushed. The leaves are high in oils and slow to compost and may collect in mounds beneath trees.

Flowers: Avocado flowers appear in January - March before the first seasonal growth, in terminal panicles of 200 - 300 small yellow-green blooms. Each panicle will produce only one to three fruits. The flowers are perfect, but are either receptive to pollen in the morning and shed pollen the following afternoon (type A), or are receptive to pollen in the afternoon, and shed pollen the following morning (type B). About 5% of flowers are defective in form and sterile. Production is best with cross-pollination between types A and B. The flowers attract bees and hoverflies and pollination usually good except during cool weather. Off-season blooms may appear during the year and often set fruit. Some cultivars bloom and set fruit in alternate years.

Fruits: West Indian type avocados produce enormous, smooth round, glossy green fruits that are low in oil and weigh up to 2 pounds. Guatemalan types produce medium ovoid or pear-shaped, pebbled green fruits that turn blackish-green when ripe. The fruit of Mexican varieties are small (6 - 10 ounces) with paper-thin skins that turn glossy green or black when ripe. The flesh of avocados is deep green near the skin, becoming yellowish nearer the single large, inedible ovoid seed. The flesh is hard when harvested but softens to a buttery texture. Wind-caused abrasion can scar the skin, forming cracks which extend into the flesh. "Cukes" are seedless, pickle-shaped fruits. Off-season fruit should not be harvested with the main crop, but left on the tree to mature. Seeds may sprout within an avocado when it is over-mature, causing internal molds and breakdown. High in monosaturates, the oil content of avocados is second only to olives among fruits, and sometimes greater. Clinical feeding studies in humans have shown that avocado oil can reduce blood cholesterol.

Growth Habit: The avocado is a dense, evergreen tree, shedding many leaves in early spring. It is fast growing and can with age reach 24.38 meters, although usually less, and generally branches to form a broad tree. Some cultivars are columnar, others selected for nearly prostrate form. One cultivar makes a good espalier. Growth is in frequent flushes during warm weather in southern regions with only one long flush per year in cooler areas. Injury to branches causes a secretion of dulcitol, a white, powdery sugar, at scars. Roots are coarse and greedy and will raise pavement with age. Grafted plants normally produce fruit within one to two years compared to 8 - 20 years for seedlings.

Ecology: The ecological requirements of avocados vary somewhat with races. They are sensitive to frost, especially the West Indian one, being particularly susceptible during flowering. Mexican cultivars are rather less susceptible to cold than West Indian and Guatemalan cultivars. They grow well in a wide range of soil type from sandy to clay loams, but the roots must not be waterlogged. High or low pH and salinity may be a problem in some areas, as the preferred pH range is 5.5 to 6.5 and the trees are intolerant of salinity, which is found in parts of the Mekong delta.

Origins and History: The earliest known written account of the avocado in Europe is that of Martin Fernandez De Encisco ( 1470 - 1528 ) in 1519 in his book, Suma De Geografia Que Trata De Todas Las Partidas Del Mundo. The plant was first introduced to Indonesia by 1750 , Brazil in 1809 , Palestine in 1908 , and South Africa and Australia in the late 19th century. (Source: indexfresh.com ).

The evident from Spanish Conquistadores that, at the time of the Spanish conquest, avocados were grown from northern Mexico south through Central America into north-western South America and south in the Andean region as far as Peru (where the avocado had been introduced shortly before the conquest), as well as into the Andean region of Venezuela.