Note from Mr. Subjunctive: this plant was suggested, unseriously, by Mr. Brown Thumb, who said he'd mistakenly written "Mexican sour curtain" on a plant tag instead of "Mexican sour gherkin." He noted (via Twitter) that it sounded like something for my fictional botany series, so I tried writing it just to see how it would go, and below is what I came up with. How'd it work? It's at least not any weirder than any of the other fictional botany posts. In my head, actually, it's a really pretty plant, and I want one.
Your head may vary.
The Mexican sour curtain plant (Vestisperma acidophora), or cortina de vinagre (sometimes just cortina), is a tropical epiphytic plant in the family Vestispermaceae. Its native range extends from Southern Mexico, south into Guatemala and Honduras. It is a minor ornamental plant.
The plant is named for its seed heads: each flower produces from 7-20 seed "chains," which are flat, segmented, semi-transparent orange to pink pods. Dark black seeds are visible in the center of each segment. The segments are approximately 1.5 inches (4 cm) long and 0.5 to 0.75 inches (1 to 2 cm) wide. The chains are linked to one another by single, semi-flexible fibers, so the seed heads end up fan-shaped or folded like a piece of cloth, hence the common names. The terminal segment of each chain is somewhat sticky, and detaches on contact with animal fur or clothing, enabling it to hitchhike long distances from the parent plant. Within a matter of hours after the loss of a segment, the new end segment has become sticky, and its connection to the rest of its chain has loosened, so it may detach as well.
Seeds and seed pods are edible, though detached pods develop a strong, disagreeable vinegar odor after about 24 hours. Some ant species consume fallen pods. Contrary to popular belief, freshly collected seed pods are either odorless or have a very faint fruity smell. Seeds will only sprout in the rainforest canopy, not on the floor: it is thought that germination is triggered by chemicals in the bark of some types of tree, and possibly also by light levels.
When sprouted, the seeds quickly develop strong, thick whitish roots, which attach to the host tree. Vestisperma leaves are large (to 10 in / 25 cm long and 4 in / 10 cm wide), broad silvery ovals with the veins traced in dark green: they form loose upright rosettes which accumulate debris from the canopy, which nourishes the roots as it decomposes. The leaves are eaten by a number of caterpillars, slugs, snails, and beetles.
Flowering may occur at any time of year but is most common in fall. The flowers typically hang down slightly below the host tree's branch, well below the leaves and roots. Flowers entirely lack petals and sepals, and consist of clusters of very long (to 4 inches / 10 cm) orange or pink stamens and pistils, with each pistil being located in the center of a set of four stamens. A given inflorescence may contain up to thirty pistils. Flower color does not appear to correlate with seed pod color. The flowers have a peculiar, distinctive smell, described most precisely by a graduate student of the author's acquaintance as "a new car interior that's been rubbed with crushed raspberries." [I know, it sounds ridiculous, but it's dead-on. -Ed.] The flowers are believed to be pollinated by bats and moths.
Mexican sour curtain is sometimes cultivated as an ornamental tropical, or more rarely as a houseplant, due to its showy leaves and flowers. It does best in very warm, humid environments, with bright light but no direct sun. Cultivated plants are not ordinarily allowed to go to seed: this seems to encourage more frequent blooming. In its native range, the seed pods are sometimes collected in small quantity and used in cooking.
V. acidophora is one of only four Vestisperma species known at this time. The other three, V. violacea, V. reticulata, and V. lithophila, are found further south than V. acidophora, and have smaller ranges. Though extremely rare in cultivation, V. violacea and lithophila have been hybridized with V. acidophora, and with one another. Only V. acidophora is known to have commercial applications at present.
V. violacea is larger than V. acidophora. Its leaves are solid silver with a green underside. Flowers and seed pods are violet or red-violet and reportedly smell strongly objectionable at all stages of development.
V. reticulata is extremely rare, and was designated an endangered species in 2005. Leaves are smaller than in V. acidophora, and are white or cream with a fine, netlike pattern of green veins. Seed pods are translucent, green, and much smaller than for V. acidophora. The flowers have not been described.
V. lithophila is a lithophyte, not an epiphyte, and grows at higher, cooler elevations than the other species. Its leaves are solid dark green, and much narrower relative to leaf length than other members of the genus. Flowers have the same form as V. acidophora and violacea, but are much smaller, reaching a maximum diameter of only 1.5 inches (4 cm). They are said to have a faint camphoraceous smell, and are orange. The red-orange, opaque seed pods are also small. Seed pods of V. lithophila are held erect above the plant, on sturdy stems, and are very sticky, though they do not stick to one another or to the leaves. Odor is reported as faintly vinegary.