Agave

Agave is a genus of monocot plants that come from dry parts of the Americas. These succulents are built for arid conditions, forming big rosettes of thick, tough leaves. While many are often called perennials because they take years to reach maturity and flower, most are actually monocarpic—each rosette blooms just once and then dies. A few species, however, can flower multiple times.

The leaves of most agaves have sharp teeth along the edges and a very sharp spine at the tip, and they are packed with tough fibers inside. The stem is usually very short, making the plant look stemless. When it flowers, a tall stalk—called a "quiote" in Mexico—shoots up from the center of the rosette.

Description

This stalk can reach 9 meters high, and Agave salmiana can grow even taller. The stalk bears a large cluster of short, tubular flowers, and sometimes tiny plantlets called bulbils. After the flowers are pollinated and seeds develop, the original rosette dies in monocarpic species.

But many agaves also send out rhizomatous suckers from their roots, which grow into new plants after the parent rosette withers. Not all agaves produce suckers throughout their lives; some rarely or never do, while others only produce them after flowering. A few varieties can live up to 60 years before blooming.

Agaves are often mistaken for cacti, aloes, or stonecrops because they share similar adaptations to dry environments, like storing water in their leaves. But each group belongs to a different plant family—cacti and stonecrops are eudicots, while aloes and agaves are monocots—so these similarities are due to convergent evolution.

Adaptations

The root system of an agave is a shallow network of rhizomes that efficiently captures rain, condensation, and dew. Most agaves also produce "pups"—young plants from runners. Agave vilmoriniana, the octopus agave, can produce hundreds of pups on its bloom stalk.

The leaves store water and have a coated surface that reduces evaporation. Their sharp spines discouraged ancient peoples from using the plant as a water source but were tough enough to be used as sewing needles. The sap is acidic. Some agaves bloom on stalks up to 9 meters tall, keeping the flowers out of reach of animals; smaller species like Agave lechuguilla have shorter stalks.

The name Agave comes from the Ancient Greek word agauós, meaning "illustrious" or "noble," referring to the very tall flower spikes. Carl Linnaeus established the genus in 1753 with four species, the first being Agave americana, which became the type species.

In older classification systems, agaves were placed in the lily family (Liliaceae), but DNA analysis showed that was wrong. The APG II system moved them to the family Agavaceae, and later APG III and IV folded Agavaceae into the larger family Asparagaceae, placing agaves in the subfamily Agavoideae. However, by 2020, Agavaceae had regained its status as an independent family.

Taxonomy

Agaves and their close relatives have long been difficult to classify. This is likely due to their relatively recent evolution (major diversification happened 8–10 million years ago), the ease of hybridization between species and even genera, incomplete lineage sorting, and long generation times.

Within a single species, there can be a lot of variation, especially in cultivation, where many named species may be just variants of wild types bred to look unique. DNA sequencing later showed that the genera Manfreda, Polianthes, and Prochnyanthes are actually nested within Agave, making the genus paraphyletic. Early in the 21st century, these findings led to a reclassification that merged those genera into Agave as the subgenus Manfreda.

Nomenclature

Along with related genera like Yucca, Hesperoyucca, and Hesperaloe, many agave species are popular ornamental plants in hot, dry climates because they need very little extra water. Most grow very slowly. Some are known by the common name "century plant." The Spanish word maguey refers to all large-leafed plants in the Asparagaceae family, including agaves and yuccas. Maguey flowers are eaten in many indigenous culinary traditions of Mesoamerica. In other languages, agave has different names: in Chinese, Japanese, and Korean, it is called "dragon tongue orchid." In Malta, it is called Sabbara; Agave americana is Sabbara tal-Amerika, and Agave sisalana is Sabbara ta' Sisal.