Angraecum cilaosianum

Names and Taxonomy

The accepted scientific name is Angraecum cilaosianum (Cordem.) Schltr., published in 1915. The name is listed as an accepted species in several orchid checklists and on the French and Swedish Wikipedia pages, which cite the original authorship and its placement in the genus Angraecum [1][4]. A synonym recorded in the literature is Mystacidium cilaosianum Cordem. [5]. No alternative spellings or unresolved nomenclatural issues are reported in the available sources.

How to Identify This Species

Angraecum cilaosianum is a modest‑sized epiphyte that often forms dense clumps on large horizontal branches. The stem is elongate and usually strongly curved; leaves are linear, stiff, arranged in two ranks towards the apex, and are unequally bilobed at the tip. Leaves are about 1 cm wide and appear only at the stem apex [2]. The inflorescence is basal, erect, thin, and typically bears a single flower, occasionally two; a characteristic aborted floral bud is often present at the base of each inflorescence, aiding identification [2].

The flower is small, about 1.25 cm (½ in) across, white to pale‑green, and emits a fragrance in the evening. It is borne on a short spur typical of many Angraecum species. Flowering occurs in early summer [5].

Because many Angraecum species share a similar growth habit, the combination of a single‑flowered, short inflorescence with an aborted basal bud, together with the leaf morphology, is the most reliable field signature for this species.

Native Range and Habitat

This orchid is endemic to the island of Réunion in the western Indian Ocean. In the wild it inhabits semi‑dry (semi‑arid) forest zones on the island’s mountainous interior, at elevations from 1,700 m to 2,000 m [2][5]. It grows as an epiphyte on large horizontal branches, indicating a preference for well‑ventilated canopy positions with moderate light penetration. The habitat is described as “semi‑dry forests,” suggesting a seasonal moisture regime rather than constant high humidity.

Species‑Specific Care

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Growers are advised to replicate the cool, well‑ventilated conditions of high‑altitude Réunion forests. Mounting the plant on bark or a coarse orchid mix, providing bright filtered light, and avoiding excessive moisture are sensible starting points, but precise cultural regimes have not been published for this species.

Flowering and Pollination

Flowering occurs in early summer (southern‑hemisphere December–January) in its native range, with each inflorescence bearing one (occasionally two) flowers that are about 1.25 cm across and emit an evening fragrance [5]. The flower possesses a short nectar spur, a feature typical of moth‑pollinated Angraecum species, but no direct pollinator observations have been recorded for A. cilaosianum. Consequently, pollination biology remains undocumented.

Evidence and Limitations

Information on this species is limited to a few descriptive accounts and checklist entries. Detailed horticultural protocols, precise temperature and humidity ranges, and pollinator data are not available in the consulted sources. Future field studies and cultivation trials would be valuable for refining care recommendations and understanding its reproductive ecology.