Plant of the Week 11/05/2007: Aloe vera)

Plant of the Week 11/05/2007

Aloe vera (L.) Burman f.

Photographed by: Chelsie Vandaveer
Credits: Aloe photographed at the Florida Botanical Garden..
Other Information: Olympus C-8080wz

The genus Aloe is comprised of 250 to perhaps as many as 300 species. They are distinctive plants with tight rosettes of thick, often succulent leaves. Arid land plants, Aloe are native to the Old World—western Asia, India and especially Africa. They are plants of legend mentioned in ancient Egyptian papyri, the Old Testament, Pliny’s Natural History and Dioscorides’ Materia Medica.

With so many species and so many ancient descriptions, modern botanists (post Linnaeus) have sought the one vera or ‘true’ aloe, the aloe with special medicinal properties. But the ‘true’ is lost to the ages; we really do not know which aloe the ancients cherished. There were probably several.

The aloe we now call the ‘true’ received its botanical name in 1768 by Nicolaas Laurens Burman. Coincidentally, Philip Miller named it Aloe barbadensis that same year. Before Burman, Linnaeus had labeled it Aloe perfoliata var. vera and it is probably the plant John Gerard called Aloe vulgaris (common aloe) in 1597. We are not even sure where Aloe vera originated. Linnaeus and Pliny both give an origin as India. But starting in ancient times the plant was carried wherever people traveled and is now widely spread throughout the tropics. It is perhaps most famously grown in Aruba where it was introduced in the 1840s.

In summer, Aloe vera [ah lo’ ee ver’ ah] produces a branching inflorescence each ending in a raceme of tubular yellow flowers. But it is the toothed, grayish green, fleshy leaves that make the ‘true’ aloe special. The inner portion of the leaves is filled with a clear gelatinous fluid so prized for healing.

Oddly, few people use aloe leaves correctly. Most simply pinch off a piece of the leaf and rub the broken end against the skin. But if one looks carefully there are small resin ducts through the outer green skin especially in the upper surface of the leaf. The ducts exude a yellow resin called emodin and this is a purgative. Highly valued as relief for constipation in earlier times, this resin should not be rubbed onto the skin. The upper surface of the leaf should be cut away and the clear gel scooped out gently using a spoon.

(Compiled from: Medical Botany, Plants affecting Man’s Health, W.H. Lewis and M.P.F. Elvin-Lewis, John Wiley & Sons, Inc., 1977; A-Z Encyclopedia of Garden Plants, C. Brickell and J.D. Zuk, American Horticultural Society, DK Publishing, NY, 1997; The Herball or General Historie of Plants, John Gerard, 1633 edition, reprinted Dover Publications, Inc. NY, 1975; W3Tropicos, VAST nomenclatural database, J. Solomon, Missouri Botanical Garden; Atlas of Florida Vascular Plants, R.P. Wunderlin, and B.F. Hansen, Institute for Systematic Botany, University of South Florida, Tampa, 2004 [S. M. Landry and K. N. Campbell (application development), Florida Center for Community Design and Research.])