Ferocactus peninsulae reaches a height of about 70 centimetres (28 in), rarely 2.5 meters, with a diameter of 40 centimetres (16 in). This plant is oval to club-shaped and has 12 to 20 showy, deep ribs. The thorns are grayish-red and have a yellowish or whitish tip. The central spines are banded and 4 to 15 centimeters long with the lowest central spine is flattened and curved in a hook shape and the 6 to 13 different, radial spines are slender occasionally twisted and bristle-like. The funnel-shaped flowers are red to yellow and reach a length of 5–6 centimetres (2.0–2.4 in). The fruits are spherical, yellow, up to 4.5 centimetres (1.8 in) long.[2]
^Biología, Héctor Hernández (Instituto de; Group), Succulent Plants Specialist (2012-02-06). "The IUCN Red List of Threatened Species". IUCN Red List of Threatened Species. Retrieved 2024-01-22.
^N. L. Britton; J. N. Rose (1922), The Cactaceae. Descriptions and Illustrations of Plants of the Cactus Family (in German), vol. Band III, Washington: The Carnegie Institution of Washington, p. 133
^Britton, Nathaniel Lord; Eaton, Mary E.; Rose, J. N.; Wood, Helen Adelaide (1919). The Cactaceae : descriptions and illustrations of plants of the cactus family. Washington: Carnegie Institution of Washington. doi:10.5962/bhl.title.46288.