Monographs Details: Lemaireocereus hystrix (Haw.) Britton & Rose
Authority: Britton, Nathaniel L. Flora Borinqueña.
Description:Species Description - This tall, columnar cactus was first observed, botanically, on the mainland of Porto Rico, in August 1921, when discovered, by Mrs. Horne, on the southern coast, near Parguera, and her painting, here reproduced, made in the evening of August 14th; it was found, also by Professor Britton at Salinas de Guanica, and near Ensenada; it was previously known to inhabit the small, dry islands Desecheo, Mona, and Cayo Muertos. The plant is also distributed through dry parts of Santo Domingo, Haiti, Cuba, and Jamaica, and on [ ] Island, [ ] .We find no popular Spanish name recorded; in Haiti it is known as Catastres. Lemaireocereus (commemorating Charles Lemaire, a distinguished French horticulturist, who lived from 1801 to 1891) is a genus of mostly large, columnar, leafless cacti, established by Britton and Rose in 1909, and includes about 20 species, natives of tropical America and the southwestern United States. Their ribbed and grooved, mostly simple or little-branched stems bear clusters of spines at the felted areoles on the ribs, but are without hair, or wool. The flowers, borne solitary at upper areoles, are diurnal or nocturnal; funnelform, or bell-shaped, the short tube bearing large scales in some species; the tubercled ovary bears several or many, small scales, is at first spineless, but later often develops clusters of short spines; the numerous stamens are short; the style and the corolla at length fall away from the ripening ovary. The fruit is large, fleshy and many-seeded, globular, or ovoid, spiny, or, when fully mature, spineless, and bursts irregularly, exposing many black seeds. Lemaireocereus hystrix (a porcupine) is at first a simple column, but later branches from near the base, the several, or many, stout, pointed branches ascending, or nearly upright, the plant becoming from 4 to 12 meters high, with a short trunk up to about 0.3 meter in diameter. The green joints are from 7 to 10 centimeters in diameter, with from 9 to 13 ribs, the areoles bearing clusters of gray spines about 4 centimeters long, or shorter, sometimes with brown tips. The flowers are from 7 to nearly 9 centimeters long, the tube bearing large, oblong, fleshy, green or purple scales, the limb 3 or 4 centimeters broad, when fully expanded, the inner segments oblong, white; the tubercled ovary bears small, round scales. The scarlet, ellipsoid, or subglobose fruit is 5 or 6 centimeters long, red-pulpy within, armed with clusters of short spines, which fall away. The flowers are fully expanded at night, but remain more or less open until the middle of the morning.

Discussion:Spanish Dildo Cactus Family Cactus hystrix Haworth, Supplementum Plantarum Succulentarum 73. 1819. Cereus hystrix Salm-Dyck, Observations Botanicae 2: 7. 1822. Lemaireocereus hystrix Britton and Rose, contributions from the United States National Herbarium 12: 425. 1909.