Xerophyte

Central Spines

Absent (or occasionally 1 short and straight)

Seeds

Boat-shaped, 2.1-2.2 mm long, 1.8 mm broad, comparatively large, chestnut-brown, and shining reticulate. Hilum oblong-round.

Roots

Branched.

Note

“matoana” for the occurrence in the State of Mato Grosso do Sul, Brazil.

Flowers

Funnel-shaped 21 mm long, 20 mm wide, sulphur yellow from the top of the plant, sometimes larger than the plant itself. Pericarpel 6 mm long, 5 mm broad, naked beneath, but with whitish to orangish hairs above. Receptacle 5-6 mm long, hairs whitish to orangish. Outer perianth segments pale yellow, spathulate, acute, the tip slightly toothed and pinkish. Style 12 mm tall, yellowish-white. Stigma-lobes 8, 3 mm long, white. Filaments in two rows, primary filament pale yellow 7 mm long inserted at the base of the style; Secondary 6 mm long, parietal, yellow. Anthers to 0.8 mm long, yellow. Nectar chamber of 0.4 mm wide. 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.

Ribs

About 15, vertical, 4-5 mm wide, divided by transverse minute furrows into small square, globular tubercles.

Stem

Globose, deeply imbilicate at apex, to only 25 mm diameter, reddish, dark dirty bronze or dark brown.

Radial Spines

Small. 4 more or less pectinate, on both sides, 1 or 2 pointing downwards, often 1-2 smaller upper ones up to 4 mm long, not much adpressed curved inward, shining, reddish-brown to almost black, deciduous or persistent.

Fruits

Round more or less flattened, 6-7 mm in diameter, tawny brown, dry indehiscent with scales and bristles that detach easily, pericarp membranous, fragile that break easily releasing the seed and the flower remains are persistent.

Areoles

With conspicuous dirty white wool when young contrasting strongly with the dark body, later bare, c. 2 mm apart.