[2] Oncidium alexandrae has an ovoid pseudobulb, between 8 and 10 cm (3 and 4 in) long, from the apex of which emerge two soft-textured, erect to arching, linear to strap shaped or lanceolate leaves.

[3] The gracefully arching flower spike, which can be up to 51 cm (20 in) long, emerges from the base of a recently matured pseudobulb along the centre-line of the upper basal sheath.

The slender, slightly arching column is 15 to 18 mm (0.6 to 0.7 in) long and has a pair of broad wings with fringed margins toward the apex.

Oncidium alexandrae shows many variations ranging from pure white to yellow to rose, including various highly spotted flowers.

In the 1901 edition of his Orchid Guide, Sander described 108 varieties under the synonym Odontoglossum crispum and 27 natural hybrids having the species as a possible parent.

[1] Natural hybrids include: Oncidium alexandrae is found in the montane forest of Colombia, at altitudes of between 1,800 metres (6,000 ft) and 3,000 metres (10,000 ft), including in the eastern Cordillera in the departments of Cundinamarca and Boyacá and in the Andes of southern Colombia in the departments of Cauca, Putumayato and Nariño.

[3] They grow chiefly on the trunks and main branches of oak trees in partial shade and occasionally full sun.

[4] The species was discovered in 1841 by Karl Theodor Hartweg,[4] in the high Andes Mountains, near Pacho in the department of Cundinamarca, Colombia, during one of his plant collecting expeditions for the Royal Horticultural Society.

English growers had initially believed that the Colombian tropics were hot and steaming jungles and tried to grow the plant in the hot-houses favoured by Victorian horticulturists.

Amongst the Veitch collectors were David Bowman, who successfully located it in Colombia in 1867,[10] Henry Chesterton who discovered a variety that has been called var.

In the meantime, the collector would build "a wooden stage of sufficient length to bear the plunder expected" where he would clean, sort and dry the orchids.

A European cannot explore that green wilderness overhead; if he could, his accumulations would be so slow and costly as to raise the proceeds to an impossible figure.

"[14]Oncidium alexandrae (as Odontoglossum crispum) appears frequently in the illustrations of John Day in his scrapbooks – 40 times between 1865 and 1887.