Hoya aldrichii , commonly known as the Christmas Island Waxvine is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of flowering plant

Flowering plant

The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...

 in the Apocynaceae

Apocynaceae

The Apocynaceae or dogbane family is a family of flowering plants that includes trees, shrubs, herbs, and lianas.Many species are tall trees found in tropical rainforests, and most are from the tropics and subtropics, but some grow in tropical dry, xeric environments. There are also perennial herbs...

 or dogbane family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

. It is a vine

Vine

A vine in the narrowest sense is the grapevine , but more generally it can refer to any plant with a growth habit of trailing or scandent, that is to say climbing, stems or runners...

 that is endemic to Christmas Island

Christmas Island

The Territory of Christmas Island is a territory of Australia in the Indian Ocean. It is located northwest of the Western Australian city of Perth, south of the Indonesian capital, Jakarta, and ENE of the Cocos Islands....

, an Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

n territory in the north-eastern Indian Ocean

Indian Ocean

The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...

, where it is a common epiphyte

Epiphyte

An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...

 in the shrubland

Shrubland

Shrubland, scrubland, scrub or brush is a plant community characterized by vegetation dominated by shrubs, often also including grasses, herbs, and geophytes. Shrubland may either occur naturally or be the result of human activity...

s of the island’s coastal terraces

Marine terrace

A marine terrace, coastal terrace, raised beach or perched coastline is a relatively flat, horizontal or gently inclined surface of marine origin, mostly an old abrasion platform which has been lifted out of the sphere of wave activity . Thus it lies above or under the current sea level, depending...

. The specific epithet honours Captain Aldrich, commander of the survey vessel HMS Egeria, which visited Christmas Island in 1887.

Description

Hoya aldrichii is a tall climber. Its stems are glabrous

Glabrousness

Glabrousness is the technical term for an anatomically atypical lack of hair, down, or similar structures...

 with pale bark. The leaves

Leaf

A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....

 are elliptical

Ellipse

In geometry, an ellipse is a plane curve that results from the intersection of a cone by a plane in a way that produces a closed curve. Circles are special cases of ellipses, obtained when the cutting plane is orthogonal to the cone's axis...

, rounded at the base, entire

Leaf shape

In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...

, acuminate or acute and glabrous; they are 75–150 mm long, 35–60 mm wide, with a 10–15 mm long petiole

Petiole (botany)

In botany, the petiole is the stalk attaching the leaf blade to the stem. The petiole usually has the same internal structure as the stem. Outgrowths appearing on each side of the petiole are called stipules. Leaves lacking a petiole are called sessile, or clasping when they partly surround the...

. The flowers occur in umbel

Umbel

An umbel is an inflorescence which consists of a number of short flower stalks which are equal in length and spread from a common point, somewhat like umbrella ribs....

s of 15–30, are white through pink to deep purple-pink in colour, and are fragrant at night. The seeds are oblong and about 5 mm long.

Taxonomy

The vine has at times been considered close to, or even synonymous with, H. cinnamomifolia

Hoya cinnamomifolia

Hoya cinnamomifolia is a vine that comes from the island of Java. It is one of the larger members of the Hoya genus with typically one leaf per node. Each leaf is large, dark green, and has lighter colored vains that run parallel to the leaf. The leaves can get as big as 15cm by 6cm...

Hook., H. pottsii Traill., and H. diversifolia Blume.