Discocactus buenekeri
Discocactus buenekeri is a species of Discocactus found in Brazil.
Description
Discocactus buenekeri is a small cactus species that can form clumps up to in diameter, arising from lateral shoots and seedlings. Individual stems, typically in diameter and tall, are a dull grayish-green and often grow buried in the soil, developing a napiform or turnip-like shape. The plant possesses a primary root that can extend up to 1 meter near the surface, sometimes accompanied by a secondary root reaching one-third that length. The stems are characterized by 14 to 19 prominent, rounded ribs, wide, that run vertically or spirally. These ribs are slightly decurrent and appear divided into tubercles about wide at their base, which can make them indistinct on mature plants. Oval areoles, wide and long, are situated on these tubercles, spaced apart. Initially covered in white wool, the areoles become bare with age. The spines are flexible, thin, and not sharp, initially white with light brown tips, later turning gray. Some spines may be twisted and curved towards the stem. There are no central spines, but 14 to 18 radial spines, measuring long, are present. Occasionally, two small accessory spines, only long and pointing upwards, may also be found.Adult plants develop a woolly cephalium at their apex, measuring approximately in height and up to in diameter. This structure, composed of white wool and occasional straight, dark brown bristles up to long at its edge, serves to protect the plant's sensitive tip from cold nights and intense UV radiation. The cephalium is also thought to attract pollinators due to its showy appearance even before flowering. The flowers are white, fragrant, funnel-shaped, in diameter and height, and emerge from the cephalium's edge. They open at night, wilt the following morning, and are pollinated by moths. These flowers are self-incompatible. The buds are light pinkish-brown, and the ovary is white, appearing bare at the base and covered with naked scales higher up. The slender, ivory-white floral tube is adorned with scales long. The inner perianth segments are white and about long, while the outer segments are also long and reddish-brown externally, particularly at the tips. Stamens feature white filaments and yellow anthers that are long. The pistil is long and white, with five partially branched, ivory to white stigmas measuring long. Mature fruits are white with a greenish top and are club-shaped, measuring about long and up to wide. They split open at the tip when ripe and retain persistent floral remnants. Each fruit contains 11 to 55 shiny black, saucer-shaped seeds, measuring wide, with a testa characterized by numerous large, nipple-shaped tubercles. The embryo is globose, lacking perisperm, and the cotyledons are barely discernible.