Zamia

Zamia is a genus of cycad of the family Zamiaceae, containing around 50 species native to North, Central and South America. It is the only genus of cycads native to the United States. They are dioecious palm- or fern-like shrubs with aerial or subterranean circular stems.

Plants of this genus produce spirally arranged, pinnate leaves. Leaves are pubescent, at least when young, having branched and simple, transparent and coloured hairs. Zamia has an unusual type of venation involving the branching together of adjacent veins. It is thought that this type of venation is primitive because it is found in many ferns, as well as in Ginkgo biloba. The articulated leaflets also lack a midrib. The lower leaflets are not reduced to spines, and the petioles often have prickles.

The new leaves of a Zamia are striking, some emerging with a reddish or bronze cast (Z. roesli). Zamia picta is even more unique, being the only truly variegated cycad (having whitish/yellow speckles on the leaves).

Their sporophylls are borne in vertical rows in cones, and the megasporophyll apices are faceted or flattened, not spinose. The flechy seeds are subglobular to oblong or ellipsoidal. They are red, orange, yellow or rarely white. The endosperm is haploid, derived from the female gametophyte. Embryo is straight, with two cotyledons that are usually united at the tips and a very long, spirally twisted suspensor.

All the species of Zamia produce leafy crowns of foliage that make them choice garden specimens and most varieties branch heavily in age to produce handsome clumps. With a few exceptions, most Zamia species are found in warm, humid, tropical rainforest habitats, growing in the forest understory. Despite this, many species are still fairly adaptable, performing quite well in cultivation. They tend to like partial shade and well-drained soil, but need protection from cold weather. Established plants drought-tolerant.

At least one species, Z. pseudoparasitica, grows as an epiphyte in the branches of trees.

The name Zamia comes from the Greek azaniae, meaning "a pine cone". Species occur as far north as Georgia in the United States (Z. integrifola) to as far south as Bolivia (Z. boliviana).

Species (incomplete list)