There are a number of orchids from different parts of the world which have nothing in common with each other except for the introduction of a certain type of root. These include the South American stanhopcas, ansellias from East Africa, some species of Grammatophyllum from the Philippines, and, alone among cymbidiums, Cymbidium traceyanum from India.
In addition to producing a normal root system, when these roots have become fully or partially formed further roots then emerge along their length at right angles to them, they then turn upward and after a short time cease to grow leaving a sharp pointed tip to the end of the root which becomes very hard.
Many orchids will adapt, arid this can become noticeable in the colour of the leaves and pseudobulbs, the permanence of aerial roots, as also the length of flower spike, and sometimes the colouring of the flowers. All these aspects can be changed by the environment in which the orchid is growing. Sometimes this can be to the plant’s good, sometimes not. Occasionally, beautiful plants will be grown but finally, it will be found that every plant has problems that will arise in coaxing them to bloom. Grow- ing orchids indoors is a matter of trial and error.
Not all orchids are suitable for indoor culture. For some there is not enough light, for others insufficient heat or humidity. Those orchids which will succeed best are the shade-loving, or low-light, types. These include the paphiopedilums, some of the intergencric odontoglossums, miltonias, and in the warmer range the phalaenopsis.
Medium-light plants for the brighter windowsills include encyclias, coelogynes, some dendrobiums, cattleyas, some laelias, maxillarias, odontoglossums, oncidiums, lycastes and many more. It is the high-light, or sun-loving and usually warm-growing, orchids which should be avoided. These include vandas, ascocendas, warm- growing oncidiums, angraecums etc. It is sad that many very young Vanda seedlings are brought into this country from Thailand to be grown as house plants.
It should be emphasised here that this fantastic root formation will only be achieved where constant moisture is available to the plant. All too often plants suspended in baskets are allowed to suffer from dryness, due to the awkwardness of regular taking down and dipping, or they simply get forgotten.