Record Holders (with Quiz)

[Klipspringer]

Is the second one also an orchid?

An Early Blue Disa - there are many "Disas" in SA.
Legend has it that a queen named Disa once presented herself to King Sveas wrapped in a fishing net and nothing else. Botanical legend has it that seeing the unusual markings like a fishnet on the petals of an interesting, then unknown Cape orchid brought Queen Disa to mind when Swedish botanist Peter Bergius (1730-1790) was naming it.

The evolutionary radiation of Disa, a large orchid genus of c. 160 species, is characterized by tremendous variation in flower form and pollination systems. 19 different specialized pollination systems were recognised within 27 investigated species in the genus Disa.

[Klipspringer]

spermatophyte ... like Vanilla as well
I've got a lot of Orchids at home, they don't need fertilization (self-fertilization)

Self-pollonation does occur in some flowering plants and in some orchids.
Few plants self-pollinate without the aid of pollen vectors (such as wind or insects). The mechanism is seen most often in some legumes such as peanuts. In another legume, soybeans, the flowers open and remain receptive to insect cross pollination during the day. If this is not accomplished, the flowers self-pollinate as they are closing. Among other plants that can self-pollinate are many kinds of orchids, peas, sunflowers and tridax. Most of the self-pollinating plants have small, relatively inconspicuous flowers that shed pollen directly onto the stigma, sometimes even before the bud opens. Self-pollinated plants expend less energy in the production of pollinator attractants and can grow in areas where the kinds of insects or other animals that might visit them are absent or very scarce.

Let's have a look at orchids sex life which comes in various odd forms:

How do plants do it?
Many plants (conifers, grasses, etc.) produce extra-light pollen in copious quantities then liberate it massively into the air so it will be carried away by the wind. They do so in the hopes that a single pollen grain will accidentally land on a receptive flower of the right species. Wind pollination does work (otherwise, the species that do it would have gone extinct), but what a waste of resources! Sometimes the entire landscape is covered with a thin layer of pollen that will never serve the plant in any way.

Other plants use a more reliable pollinator than the wind - usually an insect, although occasionally a bird (a sunbird, for example) or a mammal - to carry their pollen from one flower to another. Many essentially offer an open bar: they give as a reward a generous amount of nectar and pollen and are none too picky when it comes to their suitors. Many daisy-like common flowers give off a subtle, sugary, generic odor that attracts a wide range of insects and its florets just drip with nectar. They likewise produce more pollen than they need so pollen-eating insects can have their share. The daisy can be pollinated by bees, flies, butterflies, beetles or wasps of many different species.

Scientists call such blooms promiscuous flowers. Such plants are counting on the likelihood that one of their many pollen-laden visitors will eventually land on a plant of the same species and that some of the pollen that stuck to its body as it fed will come free and ensure fertilization. That’s still a lot of pollen and nectar to give away, but at least the investment is worthwhile if they achieve pollination.

Other flowers are very specific and orchids are often in this group. Pollinator-specific flowers come in a distinct color or form, have barriers to keep unwanted pollinators out or a scent that is only appreciated by one specific pollinator or at least a limited number of pollinators, thus forming a specific plant-pollinator interaction. The plant absolutely needs the pollinator and the pollinator can’t get along without the plant. Such plants don’t need to produce as much pollen and certainly not as much nectar as promiscuous flowers but they usually do have to reward the favour of their pollinators in some way: offering pollen, nectar, oils, housing, etc.

Orchids, though, are not as charitable as most plants. Although their heavy pollen can’t be carried by the wind and they are almost always pollinated by insects (more rarely by mammals or birds), they are very stingy with their pollen. They don’t produce “quantities” of pollen, only two pollinia or pollen masses per flower. And most are not particularly generous with their nectar either. Indeed, many produce no nectar at all.
Some orchids rely on self-pollination and thus it is not necessary for flowers to produce nectar, scent, or to be colourful in order to attract pollinators.

The Satyr orchid Satyrium rupestre from Montagu lifts the two pollinaria out of the anther sacs and they move upwards to contact and rest on the stigma - done, no insect required, much energy saved!

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(A) S. rupestre plants in situ at Montagu Pass (scale bar = 50 mm). (B) Infructescence. Swollen ovaries are indicative of high fruit set (scale bar = 20 mm). (C) Close-up of autonomous self-pollination in S. rupestre flower. Both pollinia are lifted out of the anther sac, contacting the stigma, while the viscidia are still in their original position on the rostellum (scale bar = 2 mm). (D) Side view of column of flower in early bud stage. The caudicle follows the bent line of the anther sac channel (ac = anther sac channel, as = anther sac, c = caudicle, co = column, r = rostellum, s = stigma, v = viscidium). (E) Side view of column of flower in late bud stage. The rostellum is elongated and the tissue overlaying the anther sac channel has disappeared, resulting in the upward orientation of the anther sac channel. (F) front view of column of flower in late bud stage. The rostellum has a narrow central portion (scale bar d-f = 1 mm). (G) Side view of column of flower just after the onset of anthesis. The pollinia have lifted out of the anther sac and touch the stigma. A new bend of the caudicle is visible at the point of attachment to the viscidium. (H) Front view of the column of flower just after the onset of anthesis. The narrow central region of the rostellum provides a channel through which the pollinia could pass toward the stigma (scale bar g-h = 0.75 mm). (I) Side view of the column of the insect-pollinated sister species S. ligulatum after the onset of anthesis.

There are many other ways in which orchids achieve pollination whithout giving reward to the pollinators. Floral deception is particularly widespread among Orchidaceae!


So ... this is a quiz here: What's the record the orchid family as a family holds?

(Various reproduction strategies may be one aspect thereof)

[Lisbeth]

The largest family of flowering plants?

[Lisbeth]

Abstract

Orchidaceae, a family of monocotyledonous, angiospermic flowering plants, is the most species-rich family in the world with approximately 19,000-24,000 species. The family is divided into six subfamilies: Orchidoideae, Epidendroideae, Cypripediodeae, Vanilloideae, and Apostasiodeae. Its varied vegetative and floral morphology confers a high taxonomic and ornamental importance, capturing the interest of scientists and horticulturists. In addition, the wide diversity of habitats they occupy and the epiphytic growth of most species make orchids a group of ecological importance. Orchids are widely distributed in the tropics and sub-tropics of Asia, Africa, Oceania, North, Central and South Americas, and temperate regions of Asia and Europe.

[Klipspringer]

Lisbeth, but there are more now


The world’s largest and most diverse plant family – with 26,000 to 30,000 species: orchids.
Around 470 of these orchid species are indigenous to South Africa.

[Lisbeth]

I would never have thought so, because we do not see most of them as they are hidden in the tropical rain forests Surprisingly 270 are indigenous to South Africa

[Richprins]

Who knew!

Klippies and Lis!

[Klipspringer]

The high diversity in orchids may have to do with the orchids' relationship to pollinators. Pollinators play a major role in the generation of novel floral forms and diversity in orchids.

The c. 8000 orchid species that do not offer floral rewards achieve pollination by exploiting food-, mate-, or brood site-seeking behaviour of animals. This is accomplished by visual and olfactory signals that imitate either:
- food plants
- potential mates, or
- brood sites
in a way that varies from generalized approximation to precise mimicry.

Botanists recognized orchids' visual mimicry first, but lately they've uncovered even more interesting scent-based mimicry. Basically, the orchids emit chemicals that smell, to a male insect, just like the sex pheromones emitted by the female of his species.



Pollinator-driven speciation in sexually deceptive orchids

Pollinator-mediated selection has been suggested to play a major role for the origin and maintenance of the species diversity in orchids.

Sexually deceptive orchids - When insect males are stupid enough to mate with flowers
Pollination by deception is very common in orchids; about one third of orchids are deceptive, with sexual deception as an especially intriguing variety. Sexually deceptive orchids mimic the mating signals of female insects and employ male insects as pollinators, inducing them to engage in mating behaviour and pseudocopulation or even copulation.
Chemical mimicry of sex pheromones of pollinator females plays a major role in this process. Because insect mating signals are very specific, pollinator attraction by sexual deception is also very specific, each orchid only attracting one or very few insect species. This specific pollinator attraction therefore acts as a reproductive barrier and prevents gene flow among species.
Among the different sexually deceptive orchids, a well-studied genus is the European Ophrys (Orchideae) with most of the more than
200 species pollinated by species representing different genera of solitary bees, and a few species pollinated by species of solitary wasps, flies, and beetles. 98% of closely related species of this orchid genus attract different pollinators, most likely by the use of different floral odour bouquets.
Ophrys flowers produce a complex mixture of more than 100 chemical compounds.

For South African species there is however not a great deal of research data available. Two sister species of Disa were studied to evaluate the effect that minor differences in floral color, shape, and scent have on pollination. D. atricapilla and D. bivalvata have overlapping distributional ranges, occupy similar habitats, flower at the same time, and often occur sympatrically. Observations indicate that each species is pollinated almost exclusively by male wasps. D. atricapilla is pollinated by Podalonia canescens (Sphecidae), while D. bivalvata is pollinated mainly by Hemipepsis hilaris (Pompilidae). Both wasp genera appear to exhibit mate‐seeking behavior when approaching and visiting flowers. This together with the absence of a floral reward suggests that D. atricapilla and D. bivalvata are pollinated through sexual deception.
Neither species produces any obvious food reward, but both give off a floral scent. The strong perfumy scent of D. bivalvata has been characterized as "very fragrant with the odour of ripening apples". The scent of D. atricapilla is "spicy with a hint of peppermint", but is very weak. This sounds like advertising a new perfume. That's how you attract your favourite wasp guy

Floral deception is one of the great enigmas of the orchid family. First observed in the eighteenth century by the European naturalist Christian Sprengel, and firmly disbelieved by Darwin, who considered insect pollinators too smart to fall for ‘so gigantic an imposture’, floral deception is now known to occur in at least 30– 40% of the ca 27 000 species in the orchid family. Males are not too smart . Females don't visit these deceptive flowers .

[Lisbeth]

[Richprins]