Anthurium jenmanii  Engl. 1905

pronounced: an-THUR-ee-um jen-MAN-ee-eye

(Araceae – the arum family)

common name:  Birdnest Anthurium

birdnest Anthurium
leaf detail

Anthurium is from the Greek ανθος (anthos), a flower, and ουρα (oura), a tail; jenmanii is for George Samuel Jenman (1845-1902), a British gardener and botanist who was the superintendent of Castleton Botanical Garden in Jamaica, and later Government Botanist and superintendent of the Botanical Gardens in British Guiana.

spadix

The plant was first collected on Trinidad, and is found naturally on the islands of the south-eastern Caribbean. It is also found in South America’s Guiana Shield, and in the extreme northern portion of the Amazon Basin. It grows either terrestrially, or as an epiphyte on the branches of a tree, or as a lithophyte, on rocks. It is generally found at elevations of less than 500 m in moist forests, and sometimes in open dry woodlands.

Birdnest Anthuriums belong to the section Pachyneurium within the genus. The most notable characteristic of this section is in the rolling of its new leaves. Anthuriums of all other sections are rolled in a simple spiral, like a conch shell, but those of this section are rolled into two opposite spirals towards the central rib of the leaf. The birdnest shape means that, like the bird’s nest ferns, they can trap water and nutrients in the plant base.

The leaf blades are coriaceous, i.e., leathery to the touch, and are generally broadly oblanceolate to elliptic in shape. The blades near the base of the plant are obtuse and rounded, or sometimes slightly oval. The leaf margins are moderately undulate. The upper surface of the blade is semi-glossy, and a yellowish green in colour. The lower surface is only slightly glossy, and is a little paler in colour. There are between 5 and 13 primary veins on each side of the midrib, the veins near the top of the blade merging into the collective vein, a specialized vein that runs around the circumference of the blade, and is a primary characteristic in determining if a species is or is not an Anthurium. The lateral leaf veins are raised near the midrib, but slightly sunken at the margins. The tertiary veins are sunken on the upper surface and raised on the lower. Between the leaf and the petiole is the geniculum, a knee-shaped stem-like structure that allows the leaf blade to rotate a little to find itself a brighter source of light. In this species the geniculum is slightly paler and only a little thicker than the petiole. As a new leaf is produced, it is surrounded by the cataphyll, a sheathlike structure that protects the new leaf as it emerges. In this species it is sometimes purplish in colour. After the leaf has grown, the withered remains of the cataphyll often remain.

The inflorescence is, of course, a spathe and spadix, which in this case are both purple in colour. The spathe may be a lighter purple than the spadix – there is quite an amount of variation within the species. The tiny flowers on the spadix are bisexual; at anthesis the male flower parts produce pollen at a time when the female flower parts on its own inflorescence are not receptive, so the pollinating Cyclocephala beetle transfers the pollen to another plant where the female parts are receptive – self-pollination is, however, possible. If pollination is successful, the spadix will begin to grow berries containing 1 or 2 seeds. The berries are obovoid and reddish to purple in colour, paling towards the base of the spadix until the lowermost berries are almost white.

Photographed in Picnic Bay 2012

Page last updated 21st December 2016

 

 

 

 

 

 

 

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