Origin and Habitat: Close to Ytá-Ybaté, South East of Asunción, Paraguay.

• Frailea ybatensis Buining & Moser
• Frailea grahliana subs. ybatensis (Buining & G.Moser) Prestlé
• Frailea ybatense Buining & Moser

• Frailea schilinzkyana (F.Haage ex K.Schum.) Britton & Rose
• Astrophytum schilinzkyanum (F.Haage ex K.Schum.) Halda & Malina
• Cactus schilinzkyanus (F.Haage) Kuntze
• Echinocactus schilinzkyanus F.Haage ex K.Schum.
• Frailea concepcionensis Buining & G.Moser
• Frailea schilinzkyana subs. concepcionensis (Buining & G.Moser) P.J.Braun & Esteves
• Frailea friedrichii Buining & Moser
• Astrophytum friedrichii (Buining & Moser) Halda & Malina
• Frailea grahliana (F.Haage) Britton & Rose
• Astrophytum grahlianum var. ( F.Haage ex K.Schum.) Halda & Malina
• Cactus grahlianus (F.Haage) Kuntze
• Echinocactus grahlianus F.Haage ex K.Schum.
• Frailea grahliana subs. concepcionensis Prestlé
• Frailea grahliana subs. moseriana (Buining & Bredero) Prestlé
• Frailea moseriana Buining & Bredero
• Frailea moserianum (Buining & Bredero) Halda & Malina
• Frailea ignacionensis Buining & G.Moser
• Astrophytum ignacionense (Buining & Moser) Halda & Malina
• Frailea klingleriana Prestlé
• Frailea perumbilicata F.Ritter
• Astrophytum perumbilicatum (F.Ritter) Halda & Malina
• Frailea castanea var. perumbilicata (F.Ritter) Prestlé
• Frailea schilinzkyana f. cristata hort.
• Frailea ybatensis Buining & Moser
• Frailea grahliana subs. ybatensis (Buining & G.Moser) Prestlé
• Frailea ybatense Buining & Moser

Description: Frailea ybatensisSN|3634]]SN|13518]] (Occasionally misspelled "ybatense") is one of the varieties of the wide ranging and variable Frailea schilinzkyanaSN|3634]]SN|3634]]. It has less numerous spines, more numerous ribs, dark brownish-green or purple-violet stems, and citron yellow flowers opening in the afternoon. The differences with other Frailea schilinzkyanaSN|3634]]SN|3634]] are in reality very minimal and most botanist agree on the fact that both should all be included in the Frailea schilinzkyanaSN|13518]]SN|3634]].
Habit: It is a small solitary (unless damaged) perennial stem succulent that grows deep seated flat to the ground surface.
Stem: Flattened-globular somewhat depressed at apex up to 4 cm in diameter and 2,5 cm high, green to dark-green.
Ribs: Up to 24 vertical or weakly spiralling with round tubercles about 6 mm apart. Usually red to purple-violet.
Areoles: Round covered with cream-white short wool.
Spines: Bristly, curved, up to 5 more or less pectinate or radially placed on both sides, one pointing downward, one (-2) upward and rarely one central spine, all the little ragged, creamy-white.
Flowers: Apical, diurnal, radial, funnel-shaped, 30 mm broad, yellow. Pericarpel about 8 mm long, 5 mm wide, below the naked, above whitish-brown hairs. Outer perianth segments spatulate, with a very sharp tip and pale green stripes, inner ones spatulate, acute, finely ciliate, pale-yellow. Style 10 mm long, pale-yellow; stigma lobes 5 mm long pale-yellow. Stamens pale-yellow in two rows, inner ones close to the style 9 mm long, outer rows 5-7 mm long. Anthers 1 mm long yellow. The flowers are often cleistogamous (Even when their flowers do not open, they still form fruits with many seeds).
Fruits: Globular, 7 mm in diameter, brown whit pale-brownish hairs.
Seeds: Boat shaped, dark brown, glossy 1,7-1,9 mm long, 1,2-1,4 mm wide.

Bibliography: Major references and further lectures
1) 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
2) David Hunt, Nigel Taylor “The New Cactus Lexicon” DH Books, 2006
3) Edward F. Anderson “The Cactus Family” Timber Press, 2001
4) Larocca, J., Machado, M., Kiesling, R., Oakley, L., Pin, A. & Duarte, W. 2013. Frailea schilinzkyana. In: IUCN 2013. "IUCN Red List of Threatened Species." Version 2013.2. <www.iucnredlist.org>. Downloaded on 09 January 2014.
5) A.F.H. Buining & G. Moser, Succulenta (Netherlands) 50 (3): 46, 1971
6) "Alweer een artikel over Frailea's." J.J. De Morree, Succulenta (Netherlands) 68(5): 100-103, 1989.
7) "Frailea ybatensis". Piante Grasse 27(2): 132, 2007.
8) "Frailea ybatense Buining et Moser spec. nov.". A.F.H. Buining. Succulenta (Netherlands) 50(3): 46-47, 1971.
9) "Frailea’s ook in Paraguay. Ludwig Bercht & Volker Schädlich." Succulenta (Netherlands) 87(1):36-42. 2008.
10) "Growing fraileas." Angie Money. Cactusworld (BCSS) Volume 26, No. 1 March 2008.
11) "Paraguayaanse dwergen in de twintigste eeuw." Lubomir Berka, Succulenta (Netherlands) 79(5): 216-221, 2000.

Cultivation and Propagation: Fraileas are are tiny plants with comparatively big yellow flowers, often bigger than the whole plant itself and are especially suitable for those with limited growing space. They can be easily grown in a sunny windowsill or a small greenhouse. The secret for keeping Fraileas happy and growing is to pot them in a rich, porous soil with good drainage and aeration, to give them lots of water and let them dry out between waterings. Fraileas do like more water than most other cacti. If you over-pot them (in about 6-7 cm pots) they grow much better and healthier, as they can be quite short-lived if not given correct growing conditions. During winter they like cool and dry places (minimum temperature of 5-10° C) but even light frosts do not harms them. Characteristically, during the dry season plants retract completely under the ground, both in the wild and in cultivation too. Occasional light spray of water during the winter helps plants from shrivelling up too much. In the summer they like the pot to be filled with rainwater (which is always better to use than tap water) quickly absorbed by the plants, and one can almost see the little bodies swelling up. After a day or two, it is best to drain off any remaining water in the under-pots.
Sun Exposure: They enjoy full sun. In a shaded position the plants grow faster, but are not flat shaped or dark coloured.
Propagation: With fresh harvested seeds or (rarely) by grafting. The seeds germinates well. Sow the them on the soil surface, so that they can grow to a reasonable size before they have to be pricked out into a bigger tray. The seed trays go into a heated propagator on a windowsill where they catch the afternoon sun. It does not take long for the seeds to germinate, and some will do so within a day or two after sowing. When they have reached a height of about 1 cm they are pricked out into a larger tray, where they remain until they are large enough to go into individual pots.