Opuntia macrocentra

The cactus consists of smooth obovate to orbicular shaped pads that are connected to each other by the bottom edge or pad margin. Each pad is from 10–20 centimetres (4–8 in) in width and 10–20 centimetres (4–8 in) in length, but is usually wider than it is long.[3][4] The areoles, highly reduced branch structures from which spines and glochids grow, are dark in color and can be found arranged in diagonal rows on the midstem segment.[2]

Spines are produced on the upper half or the upper edge only of the pad. Each aerole will have from 1-3 central spines coming from it with the longest being 5–10 centimetres (2–4 in) in length. The largest spine will be pointed in a markedly upward direction. Spines are sometimes seen with a white or yellow tip. Flowers are produced on the upper edge of the pads.[2][4]

Flowers of Opuntia macrocentra are large sturdy flowers of bright colors. They consist of yellow petals with red lower portions forming a bright red center. The visible internal reproductive structures are pale yellow to cream in color. This cactus produces flowers in spring, usually March through June.[4] The flowers open in the midmorning, close at night and do not reopen.[5]

If the flower is pollinated, the cactus will produce small oval shaped fruits ranging in color from bright red to dull purple when ripe.[2] The fruit produced is succulent and approximately half the size of the flower, from 2.5 to 4.0 centimetres (1 to 1+5⁄8 in) in length.[2] Each fruit has between 12-16 areoles. The rind of the fruit is purple and the inner pulp and juices are light purple to clear in color. The fruit contains flattened, tan seeds that are less than approximately 4 millimetres (5⁄32 in) in length with a broad notch on one side and prominent ridge.[3][4]