Origin and Habitat: South-east of Asuncion, Paraguay.
Altitude: 100-300 metres above sea level.
Habitat: It is found growing grows between plates of sandstone, often in the umbrage of small bushes and shrubs.

• Frailea cataphracta subs. duchii (G.Moser) P.J.Braun & Esteves
• Frailea cataphracta var. duchii G.Moser

• Frailea cataphracta (Dams) Britton & Rose
• Astrophytum cataphractum (Dams) Halda & Malina
• Echinocactus cataphractus Dams

• Frailea cataphracta subs. duchii (G.Moser) P.J.Braun & Esteves
• Frailea cataphracta var. duchii G.Moser
• Frailea cataphracta subs. melitae (Buining & Bredero) P.J.Braun & Esteves
• Astrophytum melitae (Buining & Bredero) Halda & Malina
• Frailea melitae Buining & Bredero
• Frailea cataphractoides Backeb.
• Frailea matoana Buining & Bredero
• Astrophytum matoanum (Buining & Bredero) Halda & Malina
• Frailea schilinzkyana subs. matoana (Buining & Bredero) Berka
• Frailea uhligiana Backeb. in Backeb.
• Astrophytum uhligianum (Backeb.) Halda & Malina

• Frailea cataphracta subs. tuyensis (Buining & G.Moser) P.J.Braun & Esteves
• Frailea cataphracta var. tuyensis Buining & G.Moser
• Frailea pygmaea subs. tuyensis (Buining & G.Moser) D.Metzing
• Frailea pygmaea var. tuyensis (Buining & G.Moser) D.Metzing
• Frailea tuyensis (Buining & Moser) P.J.Braun & Esteves

Description: Frailea cataphractaSN|3597]]SN|3597]] subsp. duchii is an extremely diminutive cactus with unique and remarkably beautiful form. It is one of the many geographical relatives of the widespread and morphologically variable Frailea cataphractaSN|3597]]SN|3597]]. The subsp. duchii is very variable too, and some of its morphological variant was early classified as different independent species, but nowadays all this plant are considered part of a multiform subspecies, where each form is linked to others by plants with intermediate characteristics. Frailea cataphractaSN|3597]]SN|3597]] subsp. duchii distinguishes for the dirty bronze bodies with less than 18 ribs and less adpressed spines up to 4 mm long with often 1-2 central spines. The genus is cleistogamous, the colour of the flower is yellow.
Habit: It is a s small depressed perennial stem succulent that do usually not sprout much in nature, but in culture with age begins to clump around the base and grow oddly. It grows deep seated flat to the ground surface. Only in cultivation plants may have a spherical till columnar shape.
Roots: The rootstock is fleshy, turnip-like, with fine diffuse roots.
Stem: Spherical-depressed, dull-green to dirty bronze, up to 4 cm in diameter, 2,5 cm tall more or less imbilicate at apex
Ribs:less than 18 with low and broad tubercles flatted above with a purple-brown lunate, blots situated below the areoles.
Areoles: Rounded with conspicuous whitish wool.
Radial spines: 5-9 straight or slightly curved inward, up to 4 mm long, deciduous or persistent, adpressed to spreading, whitish, yellowish grey, amber coloured or reddish brown to almost black.
Central spines: Absent or 1-2.
Flowers: Apical, diurnal, radial, sulphur yellow from the top of the plant, sometimes larger than the plant itself (4 cm diameter). But don't be disappointed when the easily produced buds fail to open. Fraileas are cleistogamous meaning that their flowers produce seed without even opening. Without the need for pollination, hence the buds rarely reach full bloom and remain closed. They will open only in great heat in the hottest, brightest, afternoon sun, if at all.
Fruits: Dry indehiscent with scales and bristles that detach easily, pericarp membranous, fragile that break easily releasing the seed.
Seeds: Comparatively large, black and shining, up to 2 mm wide, with a triangular, deeply concave face.

Bibliography: Major references and further lectures
1) Walther Haage “Kakteen von A bis Z” Neumann Verlag 1981
2) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
3) James Cullen, Sabina G. Knees, H. Suzanne Cubey "The European Garden Flora Flowering Plants: A Manual for the Identification of Plants Cultivated in Europe, Both Out-of-Doors and Under Glass" Cambridge University Press, 11/Aug/2011
4) David R Hunt; Nigel P Taylor; Graham Charles; International Cactaceae Systematics Group. "The New Cactus Lexicon" dh books, 2006

Cultivation and Propagation: Frailea cataphractaSN|3597]]SN|3597]] subs. duchii is a summer grower species relatively easy to grow. It is sometime seen as a grafted plant but grows very well on its own roots too. Characteristically, during the dry season plants retract completely under the ground both in the wild and in cultivation too.
Growth rate: Fraileas are relatively short-lived plants, only lasting few years (rarely more than 10-15 years in cultivation) and, possible annuals in habitat! In fact they reseed readily around the base of the mother plant from self-set seed if kept reasonably moist during warm weather. It is a
good idea to keep restarting them from seed; what looks like a healthy big plant may suddenly die of old age without warning.
Soil: Use mineral well permeable substratum with little organic matter (peat, humus), plants may become too elongated if compost is too rich.
Repotting: Re-pot every 2 years. Use pot with good drainage.
Fertilization: It grows much faster with a low nitrogen content fertilizer in spring and summer. Potassium helps maintaining the plants compact and healthy.
Watering: Requires careful watering to keep plant compact. Water sparingly from March till October, the thin, fibrous roots suffer if there is humidity, therefore the plant should be watered only when the surrounding terrain is dry. Keep dry as soon as the temperature starts dropping in October and keep it perfectly dry in winter at temperatures from 5 to 15 degrees centigrade.
Hardiness: They need a minimum temperature of 5-10° C (but occasionally temperatures of a few degrees below 0° are not dangerous if kept on the dry side prior to, and during, cold weather). It tends to rot in winter during the resting phase, if kept wet. In the rest period no high atmospheric humidity!!
Sun Exposure: Light shade to full sun, its colour tends to richer and darker when grown in light shade. In a shaded position the plants grow faster, but are not flat shaped and dark coloured.
Uses: It is an excellent plant for container growing. It always looks good and stays small.
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: Red spiders may be effectively rubbed up by watering the infested plants from above.
- Mealy bugs: Mealy bugs occasionally 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.
- Scales: Scales are rarely a problem.
- Rot: Rot 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. To prevent rottenness it is also advisable to surround its root neck by very rough sand or grit, this help a fast water drainage.
Propagation: With fresh harvested seeds or (rarely) by grafting. Fraileas set seed (when well grown) and grow easily from seed. In fact, they are reported to set seed even if the flower doesn’t open. This self-fertilization is called cleistogamy. Seedlings dislike strong light and dry conditions and need to be repotted frequently during the first few years. However, old plants become senile and have a tendency to succumb to disease and a weak root system. At this stage, as is well known, they die suddenly. So, after they reach about 4-5 cm in diameter grow them slowly, and adopt a new repotting period, using intervals of every 3-4 years. Additionally grow them under drier conditions or with stronger sunlight. But plants are sometine grafted to accelerate growth, but the grafted plants are typical rather tall growing, compared with plants on their own roots that are usually more flat to the ground.