Lobelia gibbosa Shakespeare wrote 'What a piece of work is man, how noble in reason, how infinite in faculty....'
Blah blah one doesn't have to look far to see that as utter rubbish, but to his credit Hamlet's speech moves on to our flawed reality.
If only Shakespeare was around to praise Lobelia gibbosa Tall Lobelia, which is a true wonder of nature.
Lobelia gibbosa is a spindly annual herb about 15cm tall with a thickened stem and scale leaves, which flowers now amongst leaf litter on Marri open forest sands and sandy gravels. It is an amazing achievement for an annual to flower, ensure that it is pollinated, and provide seeds for the next season in midsummer.
Single flowers open one at a time. The exquisite little blue and white flowers are difficult for humans to see, but the plant has evolved ingenious measures to ensure pollination by insects
Here are the plants' secrets
Blah blah one doesn't have to look far to see that as utter rubbish, but to his credit Hamlet's speech moves on to our flawed reality.
If only Shakespeare was around to praise Lobelia gibbosa Tall Lobelia, which is a true wonder of nature.
Lobelia gibbosa is a spindly annual herb about 15cm tall with a thickened stem and scale leaves, which flowers now amongst leaf litter on Marri open forest sands and sandy gravels. It is an amazing achievement for an annual to flower, ensure that it is pollinated, and provide seeds for the next season in midsummer.
Single flowers open one at a time. The exquisite little blue and white flowers are difficult for humans to see, but the plant has evolved ingenious measures to ensure pollination by insects
Here are the plants' secrets
Lobelia gibbosa root mass Image Pate et al 2020 Root System - this is mind blowing!
For more information see page 257 of this book.
Lobelia gibbosa roots form a symbiotic relationship relationship with a fungus, which is called an ericoid mycorrhiza (mainly found in in the Ericaceae shrub family on poor sand and gravel soils.) Like many orchids, germinating Lobelia seeds won't develop without mycorrhizal fungi. Ericoid mycorrhizas generally develop at 15 to 60 cms below the soil surface.
Somehow the tiny Lobelia seeds manage to get 15 to 25cm below the surface, germinate, and form a clump of thick mycorrizhal roots (called coralloid roots) that are fed by the fungus through winter and early spring. The fungus could even be transferring nutrients to the Lobelia from other plants via mycorrhizas. This provides nutrient and water storage for the Lobelia, which sends up a bean like shoot after a month to begin the normal leaf formation, growth and flowering processes.
For more information see page 257 of this book.
Lobelia gibbosa roots form a symbiotic relationship relationship with a fungus, which is called an ericoid mycorrhiza (mainly found in in the Ericaceae shrub family on poor sand and gravel soils.) Like many orchids, germinating Lobelia seeds won't develop without mycorrhizal fungi. Ericoid mycorrhizas generally develop at 15 to 60 cms below the soil surface.
Somehow the tiny Lobelia seeds manage to get 15 to 25cm below the surface, germinate, and form a clump of thick mycorrizhal roots (called coralloid roots) that are fed by the fungus through winter and early spring. The fungus could even be transferring nutrients to the Lobelia from other plants via mycorrhizas. This provides nutrient and water storage for the Lobelia, which sends up a bean like shoot after a month to begin the normal leaf formation, growth and flowering processes.
Plant structure
When the soil dries the plant acts like a succulent using stored water in the root system and thickened stem, which gradually dries up from the base.
When the soil dries the plant acts like a succulent using stored water in the root system and thickened stem, which gradually dries up from the base.
White flower streaks mimic stamens, pistil and the ovary Colour
Vertebrates with red/blue/green vision can't easily distinguish small pale blue and white flowers from light brown leaf litter.
Insects can't see red and white, poorly see yellow and brown, but have good green and blue vision. A big addition is ultraviolet (UV) and insects see the colours differently depending on whether the plant tissue reflects or absorbs UV light. For an insect, blue flowers really stand out from brownish leaf litter.
Pattern
Insect eyes readily detect movement, and they are attracted to irregular edged objects that are symmetrical. Think of the rounded symmetry of daisy flowers and bilateral (right/left) symmetry of pea ... and Lobelia flowers.
A flower's reproductive parts the pistil and stamens, absorb UV light to protect them from damage, and look dark to an insect. Many flowers have (insect vision) dark bullseye spots at their centre and streaks resembling stamens to lead insects into the flower.
Vertebrates with red/blue/green vision can't easily distinguish small pale blue and white flowers from light brown leaf litter.
Insects can't see red and white, poorly see yellow and brown, but have good green and blue vision. A big addition is ultraviolet (UV) and insects see the colours differently depending on whether the plant tissue reflects or absorbs UV light. For an insect, blue flowers really stand out from brownish leaf litter.
Pattern
Insect eyes readily detect movement, and they are attracted to irregular edged objects that are symmetrical. Think of the rounded symmetry of daisy flowers and bilateral (right/left) symmetry of pea ... and Lobelia flowers.
A flower's reproductive parts the pistil and stamens, absorb UV light to protect them from damage, and look dark to an insect. Many flowers have (insect vision) dark bullseye spots at their centre and streaks resembling stamens to lead insects into the flower.
Precise Pollination
To ensure that each insect visit results in pollen transfer Lobelias use a sneaky mechanism called secondary pollen presentation.
The most common flower structure shown in the diagram (courtesy madaboutscience.com.au) has separate male and female parts with stamens that usually surround the female pistil. There is great variation depending on the plant species and type of pollinator.
If you look at the Lobelia flower, these are absent, but are simulated by white patterns.
To ensure that each insect visit results in pollen transfer Lobelias use a sneaky mechanism called secondary pollen presentation.
The most common flower structure shown in the diagram (courtesy madaboutscience.com.au) has separate male and female parts with stamens that usually surround the female pistil. There is great variation depending on the plant species and type of pollinator.
If you look at the Lobelia flower, these are absent, but are simulated by white patterns.
 'Typical' flower' with stamens separate from pistil |  Stamens and pistil missing from centre of flower |
A side view of the flower reveals the secret.
Five petals are fused into three lobes to make a tube for the insect to enter. I suspect that Lobelias lack sufficent stored moisture to produce nectar but rely on visual mimicry as do most orchids.
Stamens are united to form a tube containing the pistil, which pokes through the upper lobes and ends at the upturned ends. Anthers surrounding the inside of the tube at the (brown marked) end release pollen into it. The style slowly elongates up the stamen tube until its thickened end (stigma) grows through the anther ring and like a piston, pushes a plug of pollen out to the hairy tip.
Insects pushing into the flower lift and part the upper petal lobes to reveal the pollen-covered stamen tube tip, which smears pollen on to the insect's back. The slow piston action enable the flower to recharge the tip for several insect visits.
Five petals are fused into three lobes to make a tube for the insect to enter. I suspect that Lobelias lack sufficent stored moisture to produce nectar but rely on visual mimicry as do most orchids.
Stamens are united to form a tube containing the pistil, which pokes through the upper lobes and ends at the upturned ends. Anthers surrounding the inside of the tube at the (brown marked) end release pollen into it. The style slowly elongates up the stamen tube until its thickened end (stigma) grows through the anther ring and like a piston, pushes a plug of pollen out to the hairy tip.
Insects pushing into the flower lift and part the upper petal lobes to reveal the pollen-covered stamen tube tip, which smears pollen on to the insect's back. The slow piston action enable the flower to recharge the tip for several insect visits.
Lobelia gibbosa upper view at pollen dispensing stage
Lobelia gibbosa side view at pollen dispensing stage
Dissected Lobelia gibbosa stamen tube at pollen dispensing stage
Some days later when remaining pollen has died, the style emerges from the stamen tube into the flower allowing the stigma to unfold and reveal its inner receptive surface. As an insect enters the flower pollen from its back brushes on to the lobes and pollinates the flower.
Lobelia gibbosa at pollen receiving stage. Top view showing split end of stamen tube due to enlarged stigma emergence
Lobelia gibbosa with petals and sepals removed at pollen receiving stage showing receptive stigma lobes
'What a piece of work is Lobelia gibbosa, how noble in form, how infinite in ingenuity'.
(Foxyspeare)
(Foxyspeare)
Postscript
Later I found a group of roosting male blue banded bees in the vicinity, and read that they prefer blue flowers.
Later I found a group of roosting male blue banded bees in the vicinity, and read that they prefer blue flowers.
