Scabiosa caucasia development page 3

Scabiosa caucasia Development (page 3)

Inside the unopened florets

What are the florets like inside before they open? Microdissection reveals they are very closely packed contents which are really a marvel of spatial organisation. As the stamens are taller than the petals and are ‘pre-grown’ before opening the need to be bent to fit within the flower.

Microdissection of an early flower shows that the developing petals carpel and anthers are green in colour. These later develop a purple pigment.
Microdissection of the flower reveals the early style and anthers are green in colour. Even from an early stage, the style surface is indented. The individual loculi of the anthers are obvious
Cloe up of a dissected flower showing the loculi of the developing anthers in one floret in which the petal have been removed. Note the barbed filaments on the outside are green at wider at their base. the brown colour of the base of the flower is an artefact of dissection
A partially dissected floret showing the organisation of the flower as accessory structures prior to opening.
The internal configuration of six micro-dissected florets in which the petals have been totally or partially removed. Note that soon after dissection some anthers have begun to open, possibly as a result of desiccation. The anthers have begun become pigmented before the loculi adopt their final configuration.
In this opened up flower, the green phyllaries have long stalks. Each floret has a collar of connected processes that give rise to the pappus
A micro-dissected unopened floret cut near the top of the anthers shows the close packing of these structures
2 micro-dissected unopened florets show that the pollen is in a swollen or hydrated state at this stage in development.
A closeup of a partially dissected unopened floret in which the upper parts of the developing petals have been removed to reveal the folded stamen filaments on the outer surface of the anthers.
In this dissected floret the developing pappus has been retained but partially opened.
A dissected floret in which the pappus and green phyllaries have been removed. It seems possible that the brown pappus bristles act to constrain circumferential grow.
A dissected flower showing a central cavity penetrated by connecting structures
The carpel and 4 anthers which were isolated by microdissection of one floret. This immature configuration of the 4 loculi changes during development.

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