The genus Agave is treated here in a wide sense to include taxa previously treated as belonging to the genera Manfreda, Prochnyanthes, Polianthes and Pseudobravoa. Not all botanists are happy with this treatment, with some feeling that these genera should remain distinct, at least until further studies have been carried out. In addition, given the high species diversity found in Agave, some feel that an alternative approach could be the recognition of several smaller genera within the current circumscription of Agave[
Common Name: Maguey de Piedra
Agave kristenii is an evergreen, stemless, succulent plant forming a rosette of leaves that can be 40 - 50cm tall and 140cm in diameter. Mature plants can produce around 7 - 10 spiny leaves that can each be 30 - 79cm long and 5 - 6cm wide near the base. After several years of growth, a flowering stem that can be around 3 - 3.6 metres tall is produced, after which the rosette will die. However, the plant usually produces a number of young plants around its base that will develop as new plants[
The plant has been harvested in the past for local use as a medicine. It is worthy of cultivation as an ornamental because of its wavy Aloe-like rosette, arched cross-zoned leaves, showy prominent mammillate teeth, and delicate shaft with bright orange flowers[
Agave kristenii has an extremely small range and extent of occurrence, beings known from only one location. The species is experiences continuing decline due to collection for medicinal purposes, and an ongoing decline in habitat quality in the area. The plant is classified as 'Critically Endangered' in the IUCN Red List of Threatened Species(2019)[
Many Agave species have strong, sharp spines on the leaves and leaf tips.
In theory at least, the flowers, nectar, immature flowering stem and the centre of the rosette of all Agave species is edible and, with proper preparation, can provide a sweet, tasty foodstuff. Some species, however, contain relatively high levels of saponins (which makes them taste bitter) and some other compounds which can cause bellyache, and so these would only be eaten in times of desperation. In addition, many people may find these foods to be strongly laxative the first few times they eat them[
Southern N. America - southern Mexico (Michoacán).
Seaward facing slopes of limestone outcrops, tropical thorn forests; at elevations up to 200 metres[
Agave kristenii is a plant of the semi-arid tropics of western Mexico. It grows in a region where the mean annual temperature is 26 - 28°c, and the mean annual rainfall is 800 - 1,200mm[
Agave species generally require a sunny position, succeeding in most soils of medium-fertility so long as they are very well-drained. Most species are undemanding as to the soil pH, though those found in the wild on limestone soils will grow better in neutral to alkaline conditions. Plants are generally very tolerant of dry conditions and of extended periods of drought[
Most Agave species are monocarpic, individual rosettes living for a number of years without flowering before sending up an often very large flowering stem and then dying after flowering and setting seed. This species, however, produces a number of new rosettes from suckers or offsets during its lifespan and these new plants will continue to grow after the death of the parent plant. Over time, some species can form extensive clonal colonies by this means[
The plant is locally abundant and produces suckers, however, individuals or even entire colonies are extirpated for medicinal purposes. Its rhizome is easily extracted completely, due to its weak roots on shallow soils, sometimes growing barely over the surface of limestone rocks. Thus, its abundance is decreasing due to over collecting[
Individual plants take about 7 - 15 years in their native habitat, considerably longer in colder climates, before flowering[
Members of this genus are rarely if ever troubled by browsing deer[
This species was historically used for its anti-inflammatory properties to treat internal contusions, tumors and cancer[
Seed - surface sow in a container in a light position. The seed usually germinates in 1 - 3 months at 15 - 20°c[
]. Prick out the seedlings into individual pots of well-drained soil when they are large enough to handle and grow them on in a sunny position until they are at least 10cm tall before planting out.
Offsets and suckers can be potted up at any time they are available.
Bulbils, where produced, are an easy method of propagation. Simply pot them up and plant out at the beginning of a growing season when they are 10cm or more tall.
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