Rarely in a few orchid species, due to their individual genetic disorders, plants produce white flowers, the Alba form, instead of their original colour. These are mainly due to the absence of pigments which define the flower colouration.
Generally, white colour dominates the whole flower parts, but there are instances that the white colour dominates only a certain area of the flower.
Epiphytic orchids attach themselves to the host tree with their basal roots. Those roots provide the plant with support as well as absorb nutrients.
However, there are a set of aerial (air) roots in certain orchid species. Aerial roots arise along the length of the stem. These extraordinary roots also help the plant absorb moisture and nutrients from the atmosphere, thus helping the plant with extra resources for its healthy growth.
Each plant species tends to grow in a particular altitudinal range. Many of them won’t survive the varying climatic conditions of altitudinal differences. However, certain orchid species have evolved to a great extent to widen their populations to multitude of altitudinal ranges – from the tropical to the subalpine/alpine zone.
For example, the Crepidium sp. presented here, has a varying altitudinal range from almost 300 ft to 9800 ft MSL. But the main objective they face is to find the right pollinator, as the life cycle of many insects (the main pollinators of orchids) depend upon many factors including the altitudinal range of their existence. Not all insects can survive in varying altitudinal ranges.
To overcome this challenge, the evolutionary mechanism in orchids developed techniques to change the colouration of its flowers along the altitudinal range to attract pollinators of their habitats with ease.
In orchids, one of the petals is modified as a lip. Usually flat in shape, the lip plays the role of a landing pad for pollinators. However, there are a few genera in which the lip is quite different – pouched.
The pouch varies in shape and size, sub-cylindric, obovoid, globose etc., and plays the role of a trap. Pollinators get attracted to the colour patterns on the flower parts and get trapped in the pouch thus helping in pollinating the flower.
Leaf blades in orchids with pseudobulbs arise from the apex of the bulb, with the axis of both remaining same and in a straight line. However, there are cases in which the leaves bent perpendicularly to the axis of the bulb.
This phenomenon is very rare and occurs in only a handful of orchid species. The reason for this unique characteristic is a little vague. During my studies, it was observed that those species with perpendicularly bent leaves always grow facing a particular direction. Hence, it is to be believed that the perpendicularly bent arrangement of the leaf blade may be for receiving maximum sunlight.
Orchids have developed many resources to attract different pollinators. Nectar is one of the most prominent of those. Many floral parts have developed to great extent to contain the nectar and to attract pollinators with their own mechanisms.
A unique and not so common way to attract pollinators is by providing nectar in grooves or channels on the surface of the lip, the most exposed floral part. As the pollinators land on the lip, the shiny wet grooves or channels lead them to the pollinarium to help in pollination.
Orchids are the most fascinating plants in the entire plant kingdom. Even after more than a century of detailed study, many characteristics and behaviours of orchid plants are not documented or studied in detail.
Orchid blooms appear with duplicate floral parts – 2 lips, 2 spurs, 4 petals, 6 sepals, 2 columns etc. In some cases duplication of all flower parts happens in the same flower, but more frequently only one or two parts get duplicated. Interestingly, not all the flowers on an inflorescence show this variation, maybe a single flower to a few flowers show this freak appearance. This is due to mutations during the flower development.
Mutations in flowers are caused due to a limited gene-pool or some environmental factors. However, this phenomenon is so rare that the chances of finding an orchid plant with monstrous or freak flowers are 1 in 10,000 plants.
Several orchid species are deciduous, meaning they shed their leaves for some part of the year. Shedding of leaves helps the plant survive water loss in varying weather conditions. At the same time, many species tend to flower while they remain leafless. Flowering during leafless season increases the chances of better pollination and wind transmission of seeds.
Presented here is Dendrobium aphyllum (Roxb.) C.E.C.Fisch., during monsoon and winter months.
The apex (point away from its attachment) of the spur is generally pointed, round, obtuse, or rarely truncated. However, few orchid flowers produce spurs with its apex bilobed (also referred to as 2-lobed).
The reasons that make the apex of the spur unique is a topic least researched. However, it has to be believed that this characteristic is related to certain pollinator behaviour.