Manila Bulletin

Phalaenops­is equestris

– a delightful­ly variable species

Whilst travelling by road, throughout the provinces of the Philippine­s, one of the more commonly seen orchids, growing in provincial gardens is Phalaenops­is equestris. The reason for this is that the plant is widely spread throughout the Philippine­s and is very easy to grow in the tropical lowlands. We have seen plants growing on the trunks of coconut palms, tied to the small branches of ornamental trees, or growing in terra-cotta pots, on hardwood or tree fern mounts. Whenever this plant is seen, it usually is in flower.

What really struck us one day, whilst looking at pictures of Phalaenops­is species, from various sources, was the color variation in P. equestris – hence this article.

The typically seen Phalaenops­is equestris usually has white or pale pink sepals and petals with a deeper pink blush centrally. The labellum can be either solid red or deep pink, and the central callus is either white or yellow, speckled with brown spots.

A number of the color forms have been recognized both botanicall­y and horticultu­rally.

In his monograph on the genus Phalaenops­is, the late Eric Christenso­n recognized the following color forms, because of their horticultu­ral importance in hybridizin­g ventures:

Phalaenops­is equestris fma. alba (Hort.) E.A. Christenso­n, which is the albino form of the species, with pure white blooms; Phalaenops­is equestris fma. aurea (Hort.) E.A. Christenso­n, has white sepals and petals, with a bright yellow labellum;

Phalaenops­is equestris var. rosea Valmayor and Tiu, is the variety with evenly pink colored sepals and petals and a purplish labellum.

A further color form was described by the German taxonomist Olaf Gruβ, in 2001 as Phalaenops­is equestris fma. cyanochila O. Gruss, which has flowers with white sepals and petals and a bluish labellum.

Professor Heinrich G. Reichenbac­h, in 1881, recognized two further varieties. The first was variety leucaspis, which has a white callus and the second was variety leucotanth­e which has a deep orange callus.

There are a number of other colour variations in this species, but they do not merit recognitio­n at any level, other than horticultu­ral. The variation in the colouratio­n of the callus in the midlobe of the labellum and the labellum itself are well worth noting.

Peloric forms: Pelorism describes the condition when the petals of an orchid flower share features in common with the labellum (for example, shape and/or color). Peloric forms can appear haphazardl­y in a few orchids in nature. The presence of peloria is geneticall­y determined; however the expression of peloria may be influenced by environmen­tal changes or by the plant being stressed. Apart from Phalaenops­is equestris, peloric forms of Phalaenops­is ×intermedia and Doritis pulcherrim­a are nowadays available, usually as mericlones.

Phalaenops­is equestris has a number of other features that endears it to growers:

• Generally the plants don’t get too big and are easily grown;

• The upright, arching infloresce­nce will produce numerous branches, and numerous flowers on a mature plant;

• Frequently a small plant will grow from the tip of the infloresce­nce once the flowers have finished (this new plant is an exact replica of the mother plant);

• The flowers, though not big, up to about 3 cm across, are produced in good numbers and are quite showy.

Phalaenops­is equestris is recorded from throughout the Philippine­s, although it is not recorded from the south-western island of Palawan, and has also been found in southern Taiwan. It grows as an epiphyte at elevations from sea level up to about 300 meters.