In resupinate orchid flowers, when buds are formed they are upside down – meaning the lip and spur (if present) are on top side of the bud. As the buds develop, the pedicel twists either clockwise or anti-clockwise to invert the bud, thus arranging the lip and spur to the bottom side of the flower. This arrangement helps visiting pollinators.
(Note: Pics of spurred buds are used to make the lesson more easier).
Post 16 – 01/October/2020
Spur is the hollow slender extension from the base of the lip. Its length and size varies from species to species. It can be a minute globose to a few cm long cylindrical structure. Spurs are often straight, pendulous or slightly curved toward its apex in arrangement.
However, a few species in genera Aerides produce uncommon perpendicularly bent triangular shaped spurs.
Post 15 – 28/September/2020
When flowers arise in two opposite vertical rows on either side of the axil, the arrangement is termed distichous flower arrangement. The arrangement can be alternate or opposite.
This type of arrangement is not confined to flowers, many orchid species produce distichous leaves also.
Post 14 – 25/September/2020
When all flowers bore on sides of the axil are turned to one direction, the arrangement is termed secund flower arrangement. Probably due to its rarity in the family of orchids, a few orchid species are even named after this flower arrangement with specific names or epithets like secunda, secundum, secundus, secundiflora, secundiflorus, etc.
Many observations during my field trips have opened a new dimension in the study of pollinator behaviours with respect to secund orchid flowers.
Post 13 – 22/September/2020
When each of the many (more than 2) flower pedicels arises from around the same point at the tip of its peduncle, it is termed umbel arrangement. This arrangement is often compared to that of the struts (ribs/frame) of an umbrella.
Many of the species in genera Bulbophyllum are examples of this unique characteristic. Flowers in umbels are referred to as umbellate, or occasionally subumbellate (when flowers are almost umbellate).
Post 12 – 19/September/2020
A modified leaf considered a part of the flower is termed floral bract. The purpose of it is to support or enfold the flower, however in the case of orchid flowers it rarely enfold the flower.
Floral bracts arise from the rachis at the point of contact of the pedicel. It can be a minute triangular-like growth to a leaf-like even longer than the pedicel or the pedicellate ovary. In some species it is larger than the flower and forms a concave shape. The many characteristics of floral bracts like its length, deflexed, hairy, colours, encircling the ovary, deciduous at flowering etc., help in identifying the species.
Post 10 – 16/September/2020
Orchid fruits are in the form of a capsule or a pod, carrying thousands and thousands of dust-like seeds. Fruits are of different shapes and sizes, from a minute globose or berry like capsule to a long cylindrical pod. Fruits attain erect, sub-erect or pendulous arrangement. In some genera the pedicel elongates considerably while the fruit matures. On maturing, fruits burst open laterally by 3 or 6 slits and the minuscule sized seeds get dispersed with the help of air flow.
Many orchid fruits have interesting characteristics to observe and study. Some attain shapes that of sausages or are three-angled; in a few cases the outer surface of the capsule or pod is pubescent (with soft hairs); they are either 3 or 6 ribbed; some are with a unique beak at its apex; in a few genera the fruits mature rapidly while in others it take months; its colour varying from green to brown or brick red, even with unique purple spots and patterns.
Post 10 – 13/September/2020
Pseudobulbs of a few orchid species in genera Pleione and Porpax got a unique sheath covering. As the bulb matures, the sheath partially disintegrates to form a fine fibrous radiating set of veins either forming a net-like pattern or longitudinally converging. This characteristic helps in identifying the species while they are not in bloom or leaf-less.
Post 09 – 10/September/2020
Leaves with its surface compressed against each other at the mid-vein to form a flattened structure with equilateral edges are termed laterally compressed leaves.
Orchid genera like Dendrobium (a few species), Oberonia and Podochilus got laterally compressed leaves.
Post 08 – 07/September/2020
Spur is not an uncommon characteristic in orchid flowers. It is defined as the hollow slender extension from the base of the lip. The purpose of the spur is to hold nectar and it varies in shape and size, solitary across all genera. However, very rarely a few orchid genera flowers possess 2-spurs.
Presented here is a Satyrium sp. and its Alba form.
Post 07 – 04/September/2020