Orchidaceae
Caladenia catenata
Caladenia catenata is commonly known as Pink fingers. A small delicate ground orchid similar in height and appearance to the Blue Fairy but with pink flowers that fade to white with age.
Pollen images
Caladenia caerulea
Caladenia caerulea is commonly known as Blue Caladenia. A delicate little ground orchid with four petals spread out like a hand. As in all orchids, its pollen comes in large packets (pollinia) and is transported by insects as one unit. One pollination event is thus potentially able to pollinate thousands of ovules in the flower's ovary.
Pollen images
Calochilus robertsonii
Calochilus robertsonii is commonly known as Purplish beard orchid. The name 'beard orchid' refers to the long hairy labellum that is present in this species. The flower is generally greenish or brownish and does not stand out in the bush (in fact they are quite hard to spot). Rather than colour, It may be the hairy labellum that attracts this orchid's pollinator. This could be a male wasp which is led to believe that the hairy labellum is a female wasp waiting for fertilisation, alternatively, it may be a female wasp which mistakes the 'beard' for a site to deposit her eggs. In either case, one or several pollinia would be picked up, and on a second attempt, be transferred to another orchid.
Pollen images
Diuris pardina
Diuris pardina (may also appear as Diuris maculata in some books) is commonly known as the Leopard Orchid. Like all orchids, the pollen is dispersed as a packet, called the pollinium. Many orchid pollen grains are beautifully sculptured, yet this may have no bearing on dispersal as the pollinating agents do not come into contact with the individual grains.
The Leopard orchid is a very common orchid around Bendigo, but just what agents act as pollinators is not really known. Hour of observation may not yield a single visitor to the flower.
Pollen images
Glossodia major
The Glossodia major is commonly known as the Wax-lip Orchid. This relatively large and noticeable ground orchid has a single flower with a hooded column. As in all orchids, the masses of pollen are contained in several pollinia at the top margin of the column. Albino forms are not infrequent. Their pollen is similar in appearance to the normal purple form but it is unknown whether or not the albino form attracts the orchid's usual pollination agent.
Pollen images
Thelymitra megacalyptra
Thelymitra megacalyptra is commonly known as the Scented Sun-orchid. The mauve or lavender flowers appear 3 to 8 on a stem in October and open only in the sunshine. There are a number of very similar sun orchids in the Box-Ironbark forests. In a good year, this very common species can colour whole patches of bush with its glorious purple/blue colour.
Orchids produce their pollen in several packets called pollinia. These are relatively large structures, easily visible with the unaided eye. The pollinator usually gets one or two pollinia glued to its body when visiting the flower at the right time. The pollina contain thousands of pollen grains. As sun orchids only open in bright sunshine, it may be possible that self pollination is a last minute resort for those flowers that did not open during their lifetime.
The major pollinating agent is unknown but small flies, gnats and midges are often seen around orchid flowers.
Pollen images
Thelymitra rubra
Thelymitra rubra is commonly known as the Salmon Sun-orchid. According to Orr (1995) in the 'Orchids of Bendigo', this is chiefly a self-pollinating species. The flowers only open in bright sunshine. Like in other orchids, pollen is packaged in pollinia and the pollen also shows an intricately sculptured outer. Why? This question is particularly interesting if the orchid does not need any pollinators. Like many other orchids, the starchy tubers of this species were eaten by Aboriginals.
