Eulychnia acida


Eulychnia acida is a flowering plant in the family Cactaceae that is found in Chile.

Description

Eulychnia acida is a arborescent columnar cactus typically exhibits a tree-like form, reaching between 1.5 and 4 meters in height, though it can grow up to 7 meters in favorable conditions. It usually develops a distinct trunk about one meter long, from which it branches to form a rounded crown. Alternatively, some individuals lack a clear trunk and present a low, highly branched, and often prostrate or ascending form, rarely exceeding one meter in height. The cactus's development is often irregular and asymmetrical, a result of its struggle for moisture, leading to a disordered appearance. Its stems, which can be erect or almost prostrate and range from in diameter, are intensely spiny even from the seedling stage. The greenish-gray epidermis is often coated with accumulated dirt and dust. It is common to observe dead or dying parts alongside inactive living tissue, making it difficult to discern active from dormant areas.
The stems feature 10 to 16 broad, low ribs, with areoles spaced apart along these ribs. The spination is highly variable, characterized by almost straight, erect, needle-shaped spines that are dark brown when young, aging to gray. Each areole typically bears one to two central spines, erect and exceptionally long, measuring between 10 and, along with about 12 radial spines, oriented outwards and approximately in length.
Flowers emerge near the stem tips and are broadly bell-shaped, measuring in length and in diameter at the opening. They are white, sometimes with a pale pink central stripe. The ovary and floral tube are covered with small, ovate, imbricate scales that are fleshy at the base and tipped with acute, calloused, black points, adorned with very short tufts of dark blue to blackish-gray hairs. The inner perianth segments, long, are initially pale pink, later turning white with a pink stripe. The throat is very short and densely packed with included stamens, long, arranged within the wide, white throat. The style is short, robust, about long, rigid, and white, bearing 12 to 15 stigmatic lobes.
The fruit is globose, long and about in diameter. It is scaly, hairy, and spineless, with a fleshy, somewhat acidic pulp. The fruit is greenish-gray when immature, ripening to a brownish-yellowish green, and is crowned by the persistent floral remnants. Edible and appearing nearly bare, without wool or spines, the fruit contains dull black seeds approximately in length. The seeds are dispersed by Mimus thenca.

Distribution

Eulychnia acida's native range spans northern and central Chile, from north of Vallenar to south of Illapel found in desert and dry scrub biomes from sea level up to approximately 1300 meters in altitude. It thrives in coastal valleys and mountain slopes, often alongside other cacti like Leucostele chiloensis, and shows a preference for rocky, fog-exposed areas where condensation provides moisture to its root system. While it can be found on gentler slopes and plains with minimal water, its presence in these habitats, with rainfall rarely exceeding 50 mm annually, highlights its remarkable adaptation to extreme aridity. This species is a significant component of its native scrubland ecosystems, exhibiting considerable morphological variation influenced by both genetic factors and local environmental conditions. Capable of reaching great longevity, with some individuals surviving for centuries, Eulychnia acida plays a vital ecological role in the Huasco and Aconcagua valleys. It also engages in a highly specialized interaction, being exclusively parasitized by the hemiparasitic plant Tristerix aphyllus.

Taxonomy

First described by Rodulfo Amando Philippi in 1864, the species name "acida" derives from the Latin word for 'sour' or 'acidic,' referring to the taste of its fruit.