Zamia angustifolia

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Zamiaceae Edible: Starch Potential hazards — see below 7 iNaturalist observations

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Summary

Zamia angustifolia is a species of plant in the genus Zamia. It is found in the Bahamas, where it is threatened by habitat loss, and in Cuba, where it is abundant. Z. angustifolia has dark gray to black strobili (cones) with acuminate points. It is found in the Bahamas only at two sites on coastal sand dunes on Eleuthera. A survey in the early 2010s found only 150 plants. Z. integrifolia is also found on Eleuthera, but the two species ranges do not overlap. The limited number of plants and sites, and the development of nearby areas for housing create the highest concern for conservation of the Bahamian population of the species. Z. angustifolia is also found in semi-deciduous dry forests in eastern Cuba (Guantánamo, Oriente, and Santiago de Cuba provinces). It is abundant in Cuba, but the taxonomic relationship between the Bahamian and Cuban populations needs further study. In 1889 Gardiner and Brace listed just one Zamia species in the Bahamas, Z. angustifolia, which they referred to as "bay rush". They reported that plants of the species were harvested on Andros and New Providence islands to produce starch sold in Nassau markets. As of 2024, the Zamia plants on Andros and New Providence islands are assigned to Z. integrifolia. Z. angustifolia is part of the Zamia pumila species complex.

Description

A cycad in the Zamiaceae family found in tropical regions. The starch is edible.

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Edible Uses

All parts of this plant are potentially toxic and should not be eaten unless effective measures are taken to remove the toxins. The tuberous stems have been used as a source of starch.

Known Hazards

We have no specific information for this species, but most if not all members of this genus are believed to contain toxins. The two main toxic compounds that have been identified are cycasin and macrozamin. When ingested in sufficient quantities, these compounds are extremely poisonous to humans and many other animals, and have been shown to cause liver damage and cancer. Cycasin and macrozamin have a cumulative effect upon the body and are suspected of causing neurological disorders when ingested in small amounts over long periods of time. There is a long history of human use of this genus as a starch-rich food, but it should be noted that the plants needed to be treated in various ways in order to remove any toxic principles. Caution should be exercised even with properly prepared foods, since even then regular consumption may lead to severe health problems and death. Since many of these species are becoming increasingly rare in the wild, this is probably a food best left to times of food shortage when other, better foods, are not available.

Distribution

It is a tropical plant.

Where It Grows

Cuba, West Indies,

Cultivation

Zamia angustifolia is native to the subtropical climate of the Bahamas. Temperatures are around 27 - 30°c in summer and average about 21°c in winter with occasional lows of 9 - 10°c. Mean annual rainfall is around 1,100mm, of which around 75% falls during summer. In cultivation plants are known to have tolerated occasional light frosts. An almost universal requirement for cycads is a well-drained but moisture-retentive soil, and by far the best soils are sandy gravels and light loams which provide the required drainage and aeration necessary for good growth. Cycads will generally not grow well in clay soils unless those soils are heavily amended with sand and organic matter. A neutral soil (pH 7), is generally best for most species of cycads and allows the proper absorption of nutrients. A slightly acid soil is better for most cycads than a basic one. A relatively fast-growing species for a cycad, able to commence forming cones around 3 years after germination. The cones are easily pollinated and take about 9 months to mature. Cycad species can usually be transplanted easily even when quite large. The best time for moving them is just before the beginning of a new growing season, the roots being trimmed if they are damaged and perhaps some leaves being removed. New roots should develop quickly as the season progresses. Species in this genus form structures known as coralloid roots. These roots branch off from the taproot or secondary roots and are distinctive in that they grow laterally or upward, forming a nodular mass at the apex. These coralloid roots occur slightly below or slightly above the soil surface and generally contain cyanobacteria, also known as blue-green algae. These are able to fix atmospheric nitrogen and make it available as a nutrient to the plant. The ability to extract this important nutrient from the air explains how many cycad species are able to survive on almost sterile soils. A dioecious species, with individual plants producing either all male or all female cones. Therefore both male and female forms of the plant need to be grown if seed is required. On very rare occasions, usually when a plant has been under severe stress, it can change sex and produce either all female or all male cones.

Propagation

Seed - remove the fleshy coating and surface sow on damp sand. Fresh seed should be stored for 5 - 6 months before planting to allow the embryo to fully develop. Germination is best at around 23 - 29°c. Pot up young seedlings into a rich, moist medium, as soon as they are large enough to handle and grow on at high temperatures without any check to growth until 2 - 3 leaves have been produced at one time, otherwise they may enter dormancy.