''Zamia hamannii'' is a species of
cycad
Cycads are seed plants that typically have a stout and woody (ligneous) trunk (botany), trunk with a crown (botany), crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants o ...
in the family
Zamiaceae
The Zamiaceae are a family of cycads that are superficially palm or fern-like. They are divided into two subfamilies with eight genera and about 150 species in the tropical and subtropical regions of Africa, Australia and North and South America. ...
. The only known population grows in a small area on an island on the northwestern Caribbean coast of
Panama
Panama, officially the Republic of Panama, is a country in Latin America at the southern end of Central America, bordering South America. It is bordered by Costa Rica to the west, Colombia to the southeast, the Caribbean Sea to the north, and ...
. Most plants of the species grow in forest, but some live on sandy beaches. It was named and described in 2008.
Classification
Taylor B. et al. (2008) described ''Z. hamanni'' based on specimens from the type locality in
Bocas del Toro Province
Bocas del Toro (; meaning "Mouths of the Bull") is a Provinces of Panama, province of Panama. Its area is 4,643.9 square kilometers, comprising the mainland and nine main islands. The province consists of the Bocas del Toro Archipelago, BahÃa Al ...
, Panama. The population had previously been regarded as part of the highly variable species
''Z. skinneri''. It remains part of the
''Zamia skinneri'' species complex. Taylor B. et al. (2012) proposed that ''Z. hamanni'' evolved from ''Z. skinneri'' or its predecessor as a result of being isolated on an island.
Description
''Zamia hamanni'' is a shrub or small tree, with a stem growing up to tall and in diameter. The stem may branch at the base or the top, sometimes both. There are up to 27 leaves per crown, the average number is about 12. The leaves are long, with 5 to 10 pairs of
leaflets. Leaflets are
elliptic
In mathematics, an ellipse is a plane curve surrounding two focal points, such that for all points on the curve, the sum of the two distances to the focal points is a constant. It generalizes a circle, which is the special type of ellipse in ...
to
oblong
An oblong is an object longer than it is wide, especially a non-square rectangle.
Oblong may also refer to:
Places
* Oblong, Illinois, a village in the United States
* Oblong Township, Crawford County, Illinois, United States
* A strip of land ...
-elliptic,
acuminate
The following terms are used to describe leaf plant morphology, morphology in the description and taxonomy (biology), taxonomy of plants. Leaves may be simple (that is, the leaf blade or 'lamina' is undivided) or compound (that is, the leaf blade ...
,
plicate
Plicata, ''plicate'', ''plicated'', ''pleated'' or ''folded'' in Latin, may refer to:
* Lingua plicata, a benign condition characterized by deep grooves in the dorsum of the tongue
* Pars plicata
The pars plicata (also known as corona ciliaris ) ...
(pleated) between veins, and with
serrated
Serration is a saw-like appearance or a row of sharp or tooth-like projections. A serrated cutting edge has many small points of contact with the material being cut. By having less contact area than a smooth blade or other edge, the applied pr ...
edges. Leaflets along the middle of the stem are long and wide. The leaves are rosy-brown or rosy-pink when they emerge, covered with silvery hairs. They mature to a glossy dark green.
Reproduction
Like all ''Zamias'', ''Z. hamanni'' is
dioecious
Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...
, with individual plants bearing either male or female
stroboli or cones, but not both.
Microstrobili, male cones, are long and wide, conical-cylindrical or elongated conical-cylindrical. The microstrobili occur singly or in groups of 2 to 6, and are yellowish to brownish-yellowish. The megastrobili, female cones, are long and wide. They are cylindrical-globose, with a single megastrobolus per plant. The megastrobili emerge covered with yellow-brown to brown hairs which mature to green or greyish-green with tan to brown hairs. Seeds are long and wide. There are up to 300 seeds in a mature cone. The
sarcotesta
The sarcotesta is a fleshy seedcoat, a type of testa. Examples of seeds with a sarcotesta are pomegranate, ginkgo
''Ginkgo'' is a genus of non-flowering seed plants, assigned to the gymnosperms. The scientific name is also used as the Eng ...
(seed coat) is bright red on a mature seed. Strobili appear annually. Pollination occurs in September and October. While a pollination agent has not been definitely identified, beetles of the genus ''
Pharaxonotha'' have been observed in male cones, and species of that genus are known pollinators of some other species of ''Zamia''. Pollination has been observed to occur twice in a year in ''Z. hamanni''.
Habitat
''Zamia hamanni'' grows on soils with lots of
humus
In classical soil science, humus is the dark organic matter in soil that is formed by the decomposition of plant and animal matter. It is a kind of soil organic matter. It is rich in nutrients and retains moisture in the soil. Humus is the Lati ...
in coastal lowlands or on sandy beaches subject to occasional salt-water overflow. The only known population is on an island, confined to less than , and consists of about 1,000 plants. Most of the population grows on high humus soil on steep hillsides, sometimes overhanging the ocean. About 10% of the plants grow on beaches in small coves protected from the full force of storms, but still subject to occasional submersion in sea water. The beach plants are exposed to more sun than the others, and are generally shorter and have smaller leaves than do the plants away from the beaches. Very few seedlings were seen on the beaches. As of 2024, the habitat is relatively unthreatened, but development of resorts on the island in the future would pose a threat.
References
Sources
*
*
External links
*
{{Taxonbar, from=Q15611668
hamannii
Flora of Panama