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Accepted Scientific Name: Melocactus harlowii (Britton & Rose) Vaupel
Monatsschr. Kakteenk. 22: 66 1912
Origin and Habitat: Cuba, Provincia Oriente, Sierra de Baracoa, Rio Jauco valley, North of La Tinta, around the town of Guajimero.
Habitat and ecology: Melocactus radoczii grows on serpentine rock.
- Melocactus radoczii Mészáros
Melocactus harlowii (Britton & Rose) Vaupel
Monatsschr. Kakteenk. 22: 66 1912
- Melocactus harlowii (Britton & Rose) Vaupel
- Cactus harlowii Britton & Rose
- Melocactus acunae León
- Melocactus acunae subs. lagunaensis Mészáros
- Melocactus harlowii subs. borhidii (Mészáros) Kunte
- Melocactus borhidii Mészáros
- Melocactus harlowii subs. evae (Mészáros) Guiggi
- Melocactus evae Mészáros
- Melocactus nagyi Mészáros
- Melocactus radoczii Mészáros
Melocactus harlowii subs. perezassoi (Areces) Guiggi
Atti Soc. Ital. Sci. Nat. Mus. Civico Storia Nat. Milano 147(2): 337 2006
Description: Melocactus radoczii is a small barrel cactus that usually produces branches with time, mature plants are easily recognizable by their cephalium, that have a covering of yellowish-white wool and bright orange-red bristles, in a regular pattern, protruding above. The immature plant looks like a smallish barrel cactus, and there is nothing in its appearance that would suggest a melocactus. Melocactus radoczii, is generally included within (as a synonym of) Melocactus harlowii, suggesting that there is not really a fundamental difference between the two. More likely they are one and the same species. It has 10, densely areolated ribs with thinner, needle-shaped spines, on the whole curving upward. The young spines are orange-red, but turn yellow as they age. Most authors have dismissed Melocactus radoczii as perhaps not worthy of even varietal status, but it still has a value for a collector because they identify plants with particular characters.
Stem: Relatively small, barrel-shaped (widest medially), 11-13 cm tall and 9-12 cm in diameter (without cephalium). Old plants frequently branched, branches often as long as 20 cm.
Ribs: 10, protruding, densely areolated (11-12 areoles per 10 cm).
Spines: Thin, aciculate, on the whole curving upward, young spines orange-red becoming yellow as they age.
Central spines: 3-4, 20-25 mm long.
Radial spines: 14-16, 10-25 mm long.
Cephalium: Depressed, discoid, 3 cm high and 4.5-5.5 cm in diameter. Bristles bright orange-red, in a regular pattern, protruding 6-8 mm above the yellowish-white wool.
Flower: Small, 10-12 mm wide, bright pink The 6 stigma lobes and the stamens are light pink.
Fruits: Obovate, 14-21mm long and 7-10 mm wide, protruding part dark pink, often lighter beneath.
Seeds: Black, strongly covered with sharp warts.
Subspecies, varieties, forms and cultivars of plants belonging to the Melocactus harlowii group
- Melocactus harlowii (Britton & Rose) Vaupel: has 12 radial spines and 4 similar centrals, reddish to yellowish with age.
Flowers deep rose-red, 15-20 mm long, 10-25 mm Ø. Fruit oval very pale pink. Distribution: S-E end of Cuba.
- Melocactus harlowii subs. evae (Mészáros) Guiggi: has the largest flowers in the harlowii-group (up to 2 cm), while its stem is perhaps one of the smallest among its closest relatives. Distribution: SW of Caimanera, on the western side of Guantánamo Bay, Santiago de Cuba province, Cuba.
- Melocactus harlowii subs. perezassoi (Areces) Guiggi: has more separated areoles. Spines more numerous, yellowish when young, larger flowers, pale pink clavate fruit and larger seeds. Distribution: Jibacoa, Central Cuba.
- Melocactus radoczii Mészáros: It has 10 ribs. Areoles closely set with thinner, denser, needle-shaped spines, on the whole curving upward. The young spines are orange-red. Distribution: Sierra de Baracoa, Cuba.
Notes: The most remarkable part of a Melocactus is its cephalium a bristle-coated structure on the summit of the plant, only Melocactus , and the similar genus Discocactus possesses this type of permanent, apical, hatlike appendage. It’s only when a Melocactus reaches maturity that the cephalium begins to grow. Cylindrical, with a diameter distinctly smaller than that of the plant body below, the cephalium will keep growing for the rest of the plant’s life, but the body of the plant stops growing the moment the cephalium starts to form. As the plants age the cephalium doesn’t increase in circumference it will steadily grow taller.
Bibliography: Major references and further lectures
1) Zoltan Rigerszki, Gerard Delanoy, Endre Ujreti, Anselme Vilardebo “Melocacti of Cuba” Cactus & Company, 2007
2) Hunt, D., Taylor, N. and Charles, G. (compilers and editors). “The New Cactus Lexicon.” dh Books, Milborne Port, UK. 2006.
3) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
4) Stuart Max Walters “The European garden flora. 3.[Angiospermae], Dicotyledons. [Casuarinaceae to Aristolochiaceae]” Cambridge University Press, 1989
5) Alessandro Guiggi “A revision of the genus Melocactus Link et Otto (Cactoideae-Cereeae) in Cuba with an appendix of the accepted status of remaining Carribean taxa” in: Cactolgy (2) 2010, pp. 23-38, Edited & published by Alessandro Guiggi.
Cultivation and Propagation: Melocacti are not the easiest things to grow and aren’t plants for beginners. It grows from April to October, and can’t endure long stretches of total dryness, and also too much water will rot it, as its weak root systems tends to be inefficient at sucking up water from wet soil. Nonetheless, again as a result of their tropical origins, they need a fair amount of water, but allow the soil to dry quite a bit before watering again. Melocacti rests from in winter (in temperate climates) but can’t stand cold, or even fairly cool temperatures, so is indispensable to keep it above 8-12°C at all times, severe damage or death occurring at temperatures that the great majority of cacti wouldn’t mind in the least and prefer more frequent water in winter than other cacti, say once a month. Do not feed in winter.
The root system is weak and generally resents being repotted and can take a long time to re-establish. The soil mix should be very quick draining, prefers very bright light, not as much as the most arid growing cacti, but plenty nonetheless.
Propagation: By Seeds or (often) graft. Sow in February-march in a light, sandy, porous soil. Cover germinating tray with glass to prevent seed from drying out. Germination is most successful at a temperature of 18 to 22° C.
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