Accepted Scientific Name: Gymnocalycium mucidum Oehme
Kakteen Sukk. 1937: 197 (-198; fig.).
Origin and Habitat: Catamarca & La Rioja, Argentina
Synonyms:
See all synonyms of Gymnocalycium mucidum
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Accepted name in llifle Database:Gymnocalycium mucidum OehmeKakteen Sukk. 1937: 197 (-198; fig.).Synonymy: 7
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Description: Gymnocalycium glaucumSN|17866]]SN|17866]] is a solitary slow growing gymno with a very peculiar glaucous grey skin, remembering at first glance of Acanthocalycium glaucumSN|52]]SN|52]], however the Acanthocalycium has a rather bluer epidermis, its areoles are differently sited and the horizontal cleft below the areole is absent. The flower of the Acanthocalycium is yellow and is produced from a brown furry bud quite unlike a Gymnocalycium flower bud.
Stem: Simple, flattened globular, distinctive bluish-grey (rather variable in colour in cultivation, and in some specimens it is almost greysh-purple)
Spines: 5–8, grey, needle shaped, somewhat bent, cream to brown coloured, with grey coating, the lower is downward directed, the other sideward directed, 1–2 cm long, variable in stoutness.
Flower: Featuring with varies shade of white or pale pink with a reddish or pinkish flush in the throat.
Fruits: Globate or fusiform, 20-40 mm long bright glaucous blue with few white bordered scales.
Seed: Large a about 1 mm.
Subspecies, varieties, forms and cultivars of plants belonging to the Gymnocalycium mucidum group
Bibliography: Major references and further lectures
1) David Hunt, Nigel Taylor “The New Cactus Lexicon” DH Books, 2006 ISBN 0953813444, 9780953813445
2) Nathaniel Lord Britton, Joseph Nelson Rose “Cactaceae: Descriptions and Illustrations of Plants of the Cactus Family” Courier Dover Publications, 1963
3) Edward F. Anderson “The Cactus Family” Timber Press, 2001
4) E. W Putnam “Gymnocalyciums” Handbook No. 5. Published by the National Cactus & Succulent Society." 1978
Cultivation and Propagation: Gymnocalycium glaucumSN|17866]]SN|17866]] is an easy to grow succulent, more cold tolerant than most and less fussy regarding soil conditions.
Growth rate: It is a relatively rapidly growing and easily flowering species that will make clumps given the best conditions.
Soils: It likes very porous standard cactus mix soil.
Repotting: Use pot with good drainage.
Watering: Water regularly in summer, but do not overwater (Rot prone), keep dry in winter.
Fertilization: Feed with a high potassium fertilizer in summer.
Hardiness: Reputedly somewhat resistant to frost if kept on the dry side prior to, and during, cold weather (hardy to -12 C ° C, or less for short periods).
Exposition: Outside bright but filtered sunlight or afternoon shade, inside it needs bright light, and some direct sun. Tends to bronze in strong light, which encourages flowering and heavy spine production.
Uses: It is an excellent plant for container growing. It always looks good and stays small. It look fine in a cold greenhouse and frame or outdoor in a rockery.
Pests & diseases: It may be attractive to a variety of insects, but plants in good condition should be nearly pest-free, particularly if they are grown in a mineral potting-mix, with good exposure and ventilation. Nonetheless, there are several pests to watch for:
- Red spiders: they may be effectively rubbed up by misting the vulnerable plants every day
- Mealy bugs: occasionally they develop aerial into the new growth among the wool with disfiguring results, but the worst types develop underground on the roots and are invisible except by their effects.
- Sciara Flies: they are one of the major problems for seedlings. It is a good practice to mulch your seedlings with a layer of grit, which will strongly discourage the flies.
- Scales: they are rarely a problem.
It is wise to treat your whole collection with a systemic insecticide twice a year in spring and autumn.
- Rot: it is only a minor problem with cacti if the plants are watered and “aired” correctly. If they are not, fungicides won't help all that much.
Propagation: Division, direct sow after last frost. Seeds germinate in 7-14 days at 21-27° C in spring, remove gradually the glass cover as soon the plants will be well rooted (ca 1-2 weeks) and keep ventilated, no full sun for young plants! To make a cutting twist off a branch and permit it to dry out a couple of weeks, lay it on the soil and insert the stem end partially into the soil. Try to keep the cutting somewhat upright so that the roots are able to grow downward.
Gymnocalycium ferrarii Rausch
