A Beginner’s Glossary of Angraecum Orchid Terms

Introduction

Angraecum orchids are a diverse group of mostly epiphytic African and Madagascan orchids. Whether you are reading a species description, a culture label, or a research paper, you will encounter many specialised terms. This glossary collects the most useful ones for beginners, gives concise definitions, and links each definition to an example from the genus.

Glossary of Angraecum Terms

Angraecum (genus)

The genus name is Latinised from the Malay word anggrek, which historically referred to epiphytic orchids of similar habit. It was established by Bory in 1804 and now includes over 200 species spread across tropical Africa, Madagascar and Sri Lanka.¹

Angraecoid

An adjective meaning “belonging to or resembling Angraecum”. It is used for species in closely related genera (e.g., Jumellea) that share a similar growth form or flower structure.⁴

Epiphytic

Growing upon another plant (usually a tree) but not parasitising it. Most Angraecum species are epiphytes, attaching their roots to bark and obtaining moisture from the air.²

Lithophytic

Growing on rocks rather than on trees. A few Angraecum species are lithophytic, developing on well‑drained rock faces.²

Monopodial

A growth habit in which a single, continuously extending stem bears leaves and aerial roots along its length. Angraecum stems are monopodial, ranging from short to elongate and often pendent.²

Stem

In Angraecum the stem may be short or elongate, unbranched or branching, and is usually covered by leaf bases that persist as a sheath.²

Leaf (general)

Leaves are thin‑textured, fleshy or coriaceous, flattened or occasionally iridiform, often bilobed at the apex and sometimes twisted at the base. They are articulated to persistent leaf‑bases.²

Distichous leaf arrangement

Leaves are arranged in two opposite rows along the stem, a common pattern in many Angraecum species.⁶

Conduplicate leaf

Leaves that are folded lengthwise, a habit noted in several Angraecum species.¹

Inflorescence

A flowering shoot that in Angraecum is axillary, bearing one to many flowers, and is usually racemose (a simple elongated cluster) or, rarely, paniculate (a branched cluster).²

Raceme

A type of inflorescence with flowers attached by short pedicels along an unbranched axis. Most Angraecum species have racemose inflorescences.²

Paniculate

A branched raceme; only a few Angraecum species produce paniculate inflorescences.²

Pedicellate vs. sessile flower

Pedicellate flowers have a short stalk (pedicel) attaching the flower to the inflorescence; sessile flowers sit directly on the axis. Both conditions occur in Angraecum.²

Flower (general)

Angraecum flowers are fleshy, ranging from small to large, often stellate (star‑shaped). The ovary is frequently twisted 180°.
²

Sepal

One of the outer perianth parts; in Angraecum the three sepals are free and usually similar in size and shape to the petals (subsimular).²

Petal

One of the inner perianth parts; like the sepals, Angraecum petals are free and often similar to the sepals.²

Labellum (lip)

The modified median petal that often serves as a landing platform for pollinators. In Angraecum it is concave, may be entire or three‑lobed, envelops the column at its base, and bears a nectar spur.²

Spur

A tubular extension of the labellum that holds nectar. Spur length is a key diagnostic character; for example, Angraecum sesquipedale has a spur over 30 cm long, reflected in its specific epithet “sesquipedale” (one‑and‑a‑half feet).⁵

Column

The fused male (stamen) and female (pistil) structure of orchid flowers. In Angraecum the column is short, fleshy, lacks a foot, and is partly enveloped by the labellum.²

Clinandrium

The shallow cavity at the base of the column that holds the pollinia. Angraecum’s clinandrium is shallow and cleft in front with a short tooth‑like rostellum.²

Rostellum

A small, often toothed projection that separates the pollinia from the stigma, preventing self‑pollination. In Angraecum it is short and located in the sinus of the clinandrium.²

Pollinia

Compact masses of pollen. Angraecum typically has two globose, sulcate pollinia, each attached to a viscidium (sticky pad) either shared or separate.²

Viscidium

The sticky pad that adheres the pollinia to a pollinator. Angraecum may have a single common viscidium or two separate ones, one per pollinium.²

Ovary

The basal part of the flower that develops into the capsule. In Angraecum it is often twisted 180° and may be sessile or pedicellate.²

Spur length (species comparison)

Spur length varies markedly: Angraecum aporoides has a straight, narrowly cylindrical spur about 0.7 cm long, whereas A. sesquipedale has a spur exceeding 30 cm.^5,6

How to Use This Glossary

When you encounter a description or label, locate the term in this list and read the definition. If a term is unfamiliar, the example species provided will help you visualise the structure on a real Angraecum plant.