Orchids are grouped according to two basic growth habits, namely: monopodials and sympodials. Monopodials are orchids with one main stem with grow taller every year. The stem lengthens, adding new leaves to the top and aerial roots occasionally form along main stem. Flowers are always borne laterally (between leaves) and successively from older nodes towards young nodes. Monopodials include Phalaenopsis, Arachnis, Vanilla, Aerides, Vandopsis, Vanda, Phyncostylis, Ascocentrum and Trichoglottis.
Sympodials are orchids with creeping ground stem or rhizome which sends out shoot which eventually develops into stem and leaves. This new growth produces its own roots and leaves at maturity. Flowers are formed at the terminals or at the sides of the stem. After flowering, another shoot is formed at the base of the proceeding growth to repeat the cycle. The stem is sometimes thickened and fleshy, forming pseudobulbs. Cattleya, Dendrobium, Oncidium, Coelogyne, Bulbophyllum, are examples of orchid general with sympodial growth habit.
Despite the complexity of the variety of orchid flowers, the structure is like any monocot flower. There are three similar sepals and petals but one of the petals is highly modified into an attractive structure known as labellum or lip. The lip attracts pollinators and serves as landing platform for pollinating insects. In the center of the flower is an organ called gynostagium, gynandium, or column. On the inner side of the column is the stigma, a shallow depression which produces a sticky solution where pollinia are deposited.
Unlike seeds of other flowering plants, orchid seeds are so minute consisting of an embryo with little or no stored food. Orchid seeds are produced literally by the thousands or even millions (Cattleya labiata) but only a few develop into mature plants.
Life of orchid seed is very critical during early stages of germination. Unless a symbiotic relationship with a beneficial fungus is established, orchid seed will die. The fungal aid or mycorrhiza is a mass of fungus hyphae, usually of species Rhizoctonia. During germination, mycorrhiza infects the basal end of the seed and releases an enzyme which converts starch, an energy of germination and enhances further its development. Orchids are limited to the environment with suitable fungus, where sugar and amino-nitrogen compounds are readily available for seed germination.
The family Orchidacease consists of about 20,000 to 35,000 species distributed into 800 genera. This constitutes roughly 10% of all flowering plants in the plant kingdom. There are many hybrids and cultivated forms which continue to increase at an average rate of more than 1,000 per year. Many endemic species are found in the Philippines, which have gained worldwide recognition by orchidists. There are about 130 genera and 941 species, of which 25 genera and 140 species based on consecutive estimates are of commercial value.
The genus Dendrobium contains a very large number of heterogenous species. It has erect, cane-type pseudobulb and bears flowers with relatively long vase-like. This group is naturally distributed in warm and humid areas, thus resulting hybrids require warm and humid environment with abundant sunlight for optimum growth and development.
- In the Philippines, the following Dendrobium hybrids appear promising for cutflower production: Purple:
- Den. Tomie, Jacquelyn Concert, Den. Norman Jackson, Den. Vera Patterson x Den. Betty Hecht; Off-White-
- Den. Jacquelyn Thomas; Yellow: Den. May Neal Crosses, Mary Mac, Bethy Ho; White: Den Water Oumme,
- Den. Neo Hawaii, Den. Jack Hawaii, Den. Multico White, Den. Jacqueline Thomas x Den. Alice Spalding,
- Den. Singapore White.
This group is generally sun-loving and robust with colorful, beautifully-shaped flowers, heavy substance and long-lasting.
Vandas are divided into three:
- Strap-leaf Vandas – These are epiphytes with flat, channeled leaves.
- Terete Vanda – Mostly terrestial plants with cylindrical, pencil-like leaves. Most commerciallyimportant hybrid is V. Miss Joaquin.
- Semi-terete Vanda – highly floriferous, making them desirable for cutflower. These are derived from crossing terete hybrid with strap leaf species/hybrid.
Cattleya and its Allies
Modern Cattleyas consists of a complex group of hybrids created by combining cattleya species or hybridization with closely allied genera such as Laelia, Brassavola, Broughtonia. Known as “Cattleya Alliance”, these are natives in Brazil, Columbia, Central America and Mexico. Genus Cattleya is a very interesting diversified group of orchids with broad spectrum of colors and types.
Some of the more famous hybrids are:
- Purple Cattleyas, like Lc. Bonanza, Blc. Norman’s Bay, Bc. Culminant;
- White Cattleyas, like C. Bow Bells, C. Bob Betts, C. General Patton, and C. General Japhet;
- Semi-Alba Cattleyas – also caled white with colored lip. Hybrids derived from C. Mossiae and C. Warscewiczis which are white with purple lips;
- Yellow Cattleyas – Blc. Malworth, Blc. Jane Helton, Blc. Malvern and Lc. Lorraine Shirai;
- Red Cattleyas – Slc. Falcon “Alwanderi”, Slc. Jewel Box, Lc. Desert Orange and Lc. Rojo.