Leuenbergeria marcanoi

Site and identification

The species description was based on plants from rocky slopes of Cerro San Francisco near Bánica in the western Dominican Republic. They grew on exposed limestone in partly deciduous forest. Current POWO gives the Dominican Republic as the natural range. In the original publication, the author cited material from southern Haiti from an earlier account, so it has not been equated here with a confirmed current range. [Areces-Mallea 1992] [2-WWW]

The older trunk is almost spineless, and its bark is rusty brown with longitudinal cracks. Leaves are elongated, distinctly pointed and almost sessile. Flowers have a purplish pink perianth. Compared with Leuenbergeria zinniiflora, the larger male-flower receptacle and the more flattened, hanging fruit are also important. [Areces-Mallea 1992]

Leaf blades are usually 3.5–7 cm long, reaching 12 cm on vigorous growth. The petiole is very short, up to about 1 mm. In the comparative key, the combination of almost sessile leaves, their elongated tips and an almost spineless older trunk is therefore important. Leaf dimensions alone partly overlap with the range of Leuenbergeria zinniiflora. [Areces-Mallea 1992]

Male and female flowers

Plants are functionally dioecious. In male flowers, the pistil is vestigial and hidden among stamens. Female flowers have a distinctly developed ovary, and stamen remnants do not perform the same function as stamens in a male flower. Distinguishing them requires examination of floral organs, since pink colour occurs in both sexes. [Areces-Mallea 1992]

Fruit flesh and unusual germination

Seeds are surrounded by a gelatinous mass formed by succulent funicles. The funicle connects the ovule, and later the seed, to placental tissue. In this species, its enlargement thus contributes to the fruit's internal structure. The outer fruit wall and flesh surrounding the seeds have different developmental origins. [Areces-Mallea 1992]

In cultivation, Leuenberger recorded a fruit in which some seeds had begun germinating. This was an observation of a specific greenhouse plant. It does not establish the frequency of this phenomenon in a natural population or a consistent reproductive strategy of the species. [Leuenberger 2008]

In the species description, ripe fruits are 2–4.5 cm long and 2.5–5.5 cm wide. They are flattened, hanging and pale green, with a fleshy wall 4–6 mm thick. They contain 105–220 seeds, usually 3.5–4 mm long. The figures come from taxonomic-description material and characterise the fruit rather than predict cultivation yield. [Areces-Mallea 1992]

Flowering in a collection

A female specimen grown by Leuenberger in Berlin-Dahlem flowered in 1984, then again in 1993 and 1998. This irregularity indicates that keeping a plant for many years does not ensure annual flowering. For seed production, retaining information on specimen sex and origin and on compatible pollen availability matters, since the species is functionally dioecious. [Leuenberger 2008]