Cephalocereus senilis

Origin and Habitat: Cephalophorus senilis is endemic to Mexico, where it is distributed only in the states of Hidalgo and Veracruz (extent of occurrence is approximately 2,170 km2).
Habitat and Ecology: The species is restricted to calcareous canyons within xerophile vegetation, and is one of the dominant elements of the xerophile scrub where it grows. The house finch eats the fruits/seed in June, July and November. It.is very common on limestone hills of eastern Hidalgo, where it is often the most conspicuous plant in the landscape. Large individuals are common here and are often 15 meters high. This species is locally abundant, but there is a continuing decline in mature individuals. This is one of the most commonly used succulent species for ornamental purposes. It is removed from the wild and cultivated. Over-collection of juveniles is also an ongoing threat and likely causing an imbalance in age distributions of sub-populations. The cephalia of this species is cut to obtain fruits and seeds. The species may be at risk from pastoral agriculture.

Synonyms:

• Cephalocereus senilis (Haw.) Pfeiff.
• Cactus bradypus Lehm.
• Cactus senilis Haw.
• Cephalophorus senilis (Haw.) Lem.
• Cereus senilis (Haw.) DC.
• Echinocactus senilis (Haw.) Beaton
• Echinocactus staplesiae Tate
• Pilocereus senilis (Haw.) Lem.

Common Names include:
ENGLISH: Old Man Cactus, Bunny Cactus, Old Man of Maexico, White Persian Cat Cactus
FINNISH (Suomi): Vaarinkaktus
FRENCH (Français): Tête de vieillard
ITALIAN (Italiano): Testa di vecchio
PERSIAN (فارسی): کاکتوس پیرمرد
SLOVAK (Slovenčina): Hlavovec starecký
SPANISH (Español): Viejo, Cactus el Viejito, Viejito, Barba de Viejo, Cabeza de Viejo
SWEDISH (Svenska): Gubbhuvud
TAMIL (தமிழ்): கிழவன் கள்ளி
THAI (ภาษาไทย): เฒ่าหัวหงอก

 

Description: Cephalophorus senilis is a columnar and erect cactus 6 to 10 or even 15 meters high, simple or branching only basally. The flowering areoles develop an abundance of wool which confluently forms a dense mass called a pseudocephalium at the top or on one side near the top. The flowers are nocturnal red, yellow, or white, though the plant may not flower until 10–20 years old. The fruit usually are obovoid. The most striking feature is the shaggy coat of long, white silky hairs suggestive of unkempt hair on an old man and hence the name old man cactus, and similar names. The coat is a particularly striking silvery white on the young cactus; as the plant ages the stem begins to lose its covering. The hairs are modified spines and they make many a plant appear almost snow-white; they serve to protect the plant from frost and sun. However, the hairs are only the radial spines of the cactus; they conceal formidable sharp yellow central spines that belie the inoffensive appearance of the hairy covering.
Stem: Cylindrical, columnar, light to bright green, becoming grey, to 30 cm in diameter, sometime branched from the base, top rounded. The individual stems are usually unbranched, being unable to withstand the weight of side branches adequately. The ribs are numerous (20-30), low, slightly notched. Very little wood-tissue is developed and the largest individuals can easily be cut down with a pick or small knife. This species undergoes profound changes in the upper parts of the trunk at maturity (about 15 years). Tissues from that part change to originate an area specializing in the production of flowers (lateral cephalium or pseudocephalium).
Pseudocephalium: Developing on plants when about 6 meters high, broadening above, at first confined to one side but later encircling the top of the plant. The flowering zone in the lateral cephalium is characterized by its interareolar space reduction, areole size increment, and high production of long bristles and woolly hairs in the areoles (The bristles of the pseudocephalium are dense, white, twice as long as the wool). Moreover epidermis lacks of chlorenchyma (photosynthetic tissue) . The lateral cephalium of C. senilis shows modifications previously reported for the Espostoa species with lateral cephalium.
Areoles: 7 mm long by 5 mm wide, closely set (12 to 14 mm apart); the ones at base of old plants producing 20-30 weak, hairlike, white or greysh bristles (modified radial spines) 6-14 cm long, the ones in the pseudocephalium producing similar but shorter bristles intermixed with dense, tawny wool, 4 to 6 cm long.
Central spines: 1-5 (mostly 3), stout, yellowish to greyish, 1-5 cm long.
Flower: The flowers are nocturnal, solitary and grow one by one. Funnel shaped, including the ovary, 5-9 cm long, 7-8 cm in diameter, yellowish pink to rose-coloured. Pericarpels and floral tubes hairy with few scales.
Fruits: The fruits develops three to four weeks after anthesis (flowering), they are, obovoid, 2.5 to 3 cm long, rose-colored, capped by the chartaceous base of the flower. The pericarpel and flower-tube bears a few minute scales with hairs in their axils. The perianth persists on the ripening fruit. The fruits remain connected to the pseudocephalium and seeds dispersion is carried out by
birds.
Seeds: Bright black, numerous.

http://www.llifle.com/Encyclopedia/CACTI/Family/Cactaceae/6893/Cephalocereus_senilis