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.
With the onslaught of winter, the topography of the high slopes in the Himalayan range changes dramatically – from green to white. With hundreds of vehicles loaded with tourists negotiating the winding roads uphill to see and play with snow, there happens a silent migration of men and beasts downhill.
With high slopes under many feet of snow, the scope of finding food for cattle remains impossible. Not just about food and water, the temperature goes so low, that remaining in the high slopes means disaster. Hence, they move downhill where fresh fodder and favourable climatic conditions are available.
Nomads in the Himalaya face threat from habitat destruction as well as a decreasing numbers in their own population. With many challenges including financial prospects against their livelihood, many members in the nomadic community who were traditionally cattle grazers moved to towns and cities looking for other income generating jobs.
The disappearance of the nomads in the Himalaya is only a matter of time.
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.