Palms   Chamaedorea geonomiformis

Some personal observations: Chamaedorea geonomiformis is a fairly common, very handsome dwarf palm native to much of the Caribbean versant of southern Mxico and Central America. There are also disjunct populations on the Osa Peninsula (Pacific versant) of Costa Rica and, apparently, another in central Panam. Originally described from cultivated material in Europe, purportedly of Guatemalan origin, these palms are now known to be widespread in wet forests throughout the region. There has been quite a bit of debate over the years regarding the taxonomic status of the populations at the northern and southern extremes of its range, which will appear in most popular works on palms as C. tenella . It is my understanding that both Michael Grayum and Donald Hodel now appear to agree that this name is invalid, and that the morphological characters that "supposedly" separate the two are not constant throughout the species range. I fully agree with this conclusion. The traditional view is that those plants with spicate female inflorescences, short apical notches on their leaves and "glossier" leaf laminas are C. tenella , with plants in the central portion of the species range (Guatemala and Honduras) being considered textbook C. geonomiformis . It is also my understanding that plants in cultivation in the U.S. and Australia are largely of Belizean and Mexican origin.

Figure 1. C. geonomiformis leaf detail.

Plants grow to ca. 1.85 m tall (6), although most mature individuals are closer to 1.00 m (3+) in overall height. They share their habitats with a fair number of other Chamaedorea spp . throughout their range, but are perhaps most closely associated with C. ernesti-augustii and C. oblongata in northern Central America. I have also found them growing in sympatry with C. neurochlamys , C. nationsiana , C. elegans , C. adscendens , C. cf. falcifera , C. schippii and C. tepejilote . In my experience, they tend to be located in shadier pockets within any given forest. While they are most often encountered in tropical forests, they do range up into premontane habitats between 900 and 1,000 m.a.s.l.

I would characterize this palm as very easy to grow, quick to mature to flowering size from seed, and tolerant of more abuse than many other species in the genus with simple leaves. It is a superb pot plant. I would suggest sharp drainage, bright shade and warm, humid conditions as the preferred cultural regimen for this species. It has been saddled with the common name of "necklace palm", apparently in reference to the similarity between ripe infructescences and strings of black pearls. Some creative soul in the trade HAS to come up with a better moniker for this palm than this one...

Figure 2. C. geonomiformis in habitat (Note backpack on left for scale).

While I know that some will disagree, I consider that the finest-looking plants of this species occur on the Guatemalan-Honduran border, where they blend the physical characteristics of both forms perfectly. Some individuals show varying degrees of leaf mottling when well-cultivated, and in my mind are strongly reminiscent of certain simple leaf Pinanga spp . I grow both these plants and others from a population on Guatemalas Caribbean coast, to the exclusion of other populations. If they were to become available in culture, I would also be interested in cultivating the smaller ecotype from southwestern Costa Rica which is depicted as having glossier leaf laminas and more pronounced marginal teeth than plants from further north.

Below, I have attached a series of photos of this species in habitat and seed-grown plants in cultivation at my home. In order to bolster the argument that C. tenella is indeed a junior synonym of C. geonomiformis , for illustrative purposes Ive selected eastern Guatemalan plants that share the supposed key characters of both taxa. The wild plant is, (Figure 1&2) in my opinion, one of the finest individuals I have encountered. Please note backpack alongside for scale. This particular palm has exceptionally long and well-shaped leaves.

Figure 3. C. geonomiformis , seed-grown plant from the same population, 32 months old.

The batch of seedlings that the young female in Figure 3 came from are all noticeably "beefy", as is their mom. I used this plant to illustrate the diversity within even a small population when contrasted with the wild adult. I strongly suspect that the texture and creasing of these youngsters leaves, as well as the speed with which they started flowering is due to a constant but small excess of some nutrient that is producing very mild leaf deformity sans spotting or brown-tipping. The four year-old (Figure 4) is growing outside under more normal regimen (= gets fed when I remember to do so, rather than on a fixed schedule), so it has a flat lamina with more normal base color. The very short petioles are from the amount of light that the seedlings get under bright glasshouse culture.

Figure 4. C. geonomiformis , same population, four year-old plant showing very pale leaf mottling.

Contributed by:

Jay Vannini (Text and Figure 1,2,3&4)

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