|Photo Dennis Stevenson
|The Cycad Pages
- Zamia polymorpha "D.W. Stev., A. Moretti & Vázq. Torres", Delpinoa n.s. 37-38: 3-8 (dated 1995) (1998).
- "TYPE: Belize. Cayo: 22 Jan 1989, D. Stevenson et al. 1119 (holo NY; iso BRH, FTG, MO, NY, U)."[NY][NY][NY][NY]
The specific epithet, Z. polymorpha, is
derived from the fact that the species exhibits extreme variability
in leaf and leaflet morphology
This species, first collected at the turn
of the 20th century, was known from only three herbarium specimens which
in turn were not assigned to a species. Intensive field work in the late
1980's revealed many large populations throughout the Yucatan Peninsula
and Belize. Those plants and in some cases individual leaves that are
exposed to full sun are shorter, more narrow, coriaceous, and have
leaflets that are lanceolate and finely serrate. In contrast, those
plants, and in some cases individual leaves, that are in deep shade
have longer, broader, subcoriaceous to papyraceous leaves and have
leaflets that are elliptic to suboblanceolate. Those plants growing
under intermediate conditions exhibit leaf morphologies that are
intermediate between these two extremes. This variability in leaf
morphology was observed in all eleven populations studied. Moreover,
it was in all cases correlated with habitat so that the extremes
can be thought of as sun and shade forms. This is supported by the
fact that both extremes were observed in a few cases to exist on the
same plant where one leaf was exposed to full sun and another was
highly shaded. This in turn supplied enough material for a thorough
comparison with other species and the recoginition of its status
as a new species.
In many aspects many individual
plants of Zamia polymorpha are most similar to Z. loddigesii
Miq. These include general growth habitat, the presence of 2-3 leaves,
leaf size and shape, and leaflet size and texture. However, both
the pollen and ovulate strobili differ from Z. loddigesii
in color, overall shape and the morphology of the individual
sporophylls. The pollen cones of Z. loddigesii are brown
at pollen shedding and have microsporophylls with a large terminal
facet that obscures the presence of the six small lateral facets.
In contrast, Z. polymorpha has light tan to tan pollen cones
at pollen shedding and microsporophylls with a small terminal facet
and six prominent lateral facets. The ovulate strobilus of
Z. loddigesii is gray to very light tan and cylindrical with
a prominent prolonged and constricted acuminate, sterile tip (see
for example the color photograph on page 286 in
Jones, 1993) whereas
the ovulate strobilus of Z. polymorpha is tan to brown and
ovoid with a gradual, acute, sterile tip. Other plants of
Z. polymorpha appear similar in leaflet morphology and texture
to plants of Z. furfuracea L. fil. but they lack the distinctive
pubescence that characterizes mature leaflets of Z. furfuracea
as well as the obovate leaflets that generally characterize
Distribution and habitat:
Zamia polymorpha is endemic
to the Yucatan Peninsula of Mexico and along the eastern coast of
Belize extending westward up to 500 m on the eastern slope of the
Zamia polymorpha seems to do well in
mildly disturbed habitats where the plants are numerous with good
seed set and seedlings establishment. Not listed in the
1997 IUCN Red List of Threatened Plants.
|Photo Ken Hill
|Photo Ken Hill
Stem subterranean, subglobose, to 10 cm diam.
Cataphylls ovate, 3-4 cm long, 1.5-2.5 cm wide.
Leaves 2-3 (1-4), 0.5-1.5 m long; petiole 15-50 cm long,
sparsely to densely prickled; rachis with 3-12 pairs of leaflets.
Leaflets lanceolate to oblanceolate, cuneate basally, acute
to subacuminate apically, margins serrate in the upper two-thirds, the
larger median ones 20-30 cm long, 2-8 cm wide.
Pollen cones tan, cylindrical to ovoid-cylindrical, 6-10 cm long,
2-4 cm diam.; peduncle 2-4 cm long.
Microsporophylls with sterile tip composed of six slightly
inclined facets surrounding a small, centrally depressed terminal
facet, sporangia present on abaxial surface only.
Seed cones tan to brown, cylindrical to ovoid-cylindrical,
10-15 cm long, 5-7 cm diam.
Seeds light-red to red, 1.5-2 cm
long, 0.5-0.8 cm diam.
2n = 17, 22, 23, 24, 25, 26, 27, and 28.