Buddleja iresinoides is a species endemic to the rocky hillsides and stream banks of Bolivia

Bolivia

Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...

 and northern Argentina

Argentina

Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

 at altitudes from 300 to 1500 m. The species was correctly identified as a Buddleja and named by Hosseus

Carl Curt Hosseus

Dr Carl Curt Hosseus was a German botanist born in Stromberg im Thale, Rhineland. He gained his doctorate in 1903, and sailed Genoa in 1904 for Thailand where he found Viola hossei, which was named for him. He was the first botanist to collect in northern Thailand. A complete set of his Thai...

 in 1924.

Description

B. iresinoides is a dioecious

Dioecious

Dioecy is the property of a group of biological organisms that have males and females, but not members that have organs of both sexes at the same time. I.e., those whose individual members can usually produce only one type of gamete; each individual organism is thus distinctly female or male...

 shrub

Shrub

A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...

 1 - 3 m , occasionally < 5 m, high with light grey finely-striated bark. The pendulous branches are subquadrangular, tomentulose

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....

 or tomentose

Tomentose

Tomentose is a term used to describe plant hairs that are flattened and matted, forming a woolly coating known as tomentum. Often the hairs are silver or gray-colored...

, bearing lanceolate to ovate

Leaf shape

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

 leaves 5 - 15 cm long by 2 - 5 cm wide on 0.5 to 1.5 cm 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...

s, glabrous

Glabrousness

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

 above and tomentose, tomentulose, or even glabrescent

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....

 below. The cream inflorescence

Inflorescence

An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...

 is paniculate

Panicle

A panicle is a compound raceme, a loose, much-branched indeterminate inflorescence with pedicellate flowers attached along the secondary branches; in other words, a branched cluster of flowers in which the branches are racemes....

, 10 - 15 cm long with two orders of branches, the flowers borne in small globose heads 4 - 6 mm in diameter and comprising 3 - 12 flowers. The corolla is < 2 mm long and of differing shape depending on the sex of the plant, which led Fries to mistakenly identify two separate species (see Synonyms).