Disocactus phyllanthoides

Etymology

Phyllanthoides (lat.) = similar to phyllanthus. This species was among the first flat-stemmed species to be described, and the name recalls that it is similar to the first described flat-stemmed cactus Cactus phyllanthus today - Epiphyllum phyllanthus. Some authors state that this plant first flowered in the garden of Château de Malmaison, belonging to the late Empress Joséphine de Beauharnais. This could explain some of the popular names such as German Empress, Deutsche Kaiserin, Giant Empress, Drottningkaktus (Swedish for Queen's Cactus). This story could be a myth.

Description

Stems to 1 m long or more, branching, primary stems to 40 cm long, 6 mm thick, woody and terete at base, flattened at apex; secondary stems flat, lanceolate, acute, margins coarsely crenated or scalloped, obtusely toothed, with terete, stalk-like base, 15–30 cm long, 2,5–5 cm wide; areoles nude except for young growth; epidermis green or reddish, nearly smooth.

Flowers campanulate, funnel-shaped, diurnal and scentless*, 8–10 cm long, 7–9 cm wide, produced on year old branches; pericarpel ovate with a few spreading bracteoles; entire receptacle 2,5–5 cm long, 7–10 mm thick; bracteoles more numerous than on the pericarpel, reflexed, green to blackish purple, naked in their axills; outer tepals lanceolate, opening irregularly before flowering, then spreading widely, rose-pink; inner tepals lanceolate-obtuse, ± erect, pink, paler inside; stamens declinate, as long as the tepals, white; style as long as tepals, white, stigma lobes 5-7. Fruit ellipsoid, 3–4 cm with low ribs, green at first, later red. Seeds dark brown. J. Borg (Cacti, 1951) report it as "sweet-scented".

Taxonomy

A distinct species related to Disocactus ackermannii, D. phyllanthoides has previously been placed in Nopalxochia, but the generic status for that taxon does not have much support. This species, like others of the former Nopalxochia, shows affinity to Webereocereus making the systematics of this group even more complex.

Distribution and habitat

Known only from cultivation or sometimes naturalized.

Cultivation

Disocactus phyllanthoides is very easily cultivated. The soil should contain plenty of leaf-mould and the plant be given regular water and dozes of fertilizer in summer. Best kept relatively cool and dry in winter, 10–15 °C (50–59 °F). Plants held under proper conditions can produce flowers at least three times a year, but the main flowering period is spring.

History

This plant probably has been in cultivation since prehistoric times by the Indigenous peoples of South America and Mesoamerica. This cactus was called Nopalxochitl by the Aztecs with explains the former generic name Nopalxochia.

As with many of the early described cacti the history is somewhat unclear. Sims and Edwards state that it was discovered by the celebrated travellers Humboldt and Bonpland in April 1801, near the small village of Turbaco, near Cartagena, Colombia. Reported by Bonpland to have first flowered at Château de Malmaison and at the Botanical Garden of Montpellier, France. However, this species was illustrated much earlier. Both Hernández (1651) and Plukenet (1691) illustrated the species. Said to have come from Colombia, but may have originated in Southern Mexico.

Cultivars and hybrids

Some cultivar names are in use, but there are no evidence that these differ from the original species - 'Deutsche Kaiserin', 'Empress', 'German Empress'. However, 'Giant Empress' represent a somewhat larger clone with more uniform pink flowers.

Frequently used in hybrids. Together with Disocactus speciosus and Epiphyllum crenatum forming the great trio behind the huge group of orchid cacti known today. Other species have been used, but not by far to the same extent as these three.