Where sclerenchyma is found
Sclerenchyma is the one tissue in this chapter you can buy in a shop. Rope, coir matting, cotton thread — all of it is dead plant cells.
Where the fibres are
Inside the plant
As xylem fibres within the xylem tissue, and as phloem fibres within the phloem tissue. Both of those are met in the next two skills.
Outside, as material
Coir, hemp fibre and cotton thread are all sclerenchyma fibre cells. What makes them useful is exactly what killed them: a thick lignified wall that does not rot easily and does not stretch.
Where the sclereids are
In the stone of a fruit
In the inner covering of fruits such as coconut, kaduru and mango — the hard shell around the seed.
In fruit flesh and seed coats
In the wall of fruits such as guava and pears, and in the seed coats of dates and coffee.
The function of sclerenchyma
Providing support to the plant body.
A shell around a seed is a tissue doing its job
Sclereids in a coconut shell are not there to hold the tree up. They are there to stop anything getting at the seed. The function written in the textbook is support, but the mechanical strength a lignified wall provides is useful to a plant in more ways than one — and protecting the next generation is the most valuable of them.
The two strengthening tissues, side by side
Collenchyma is living, its cellulose walls thickened at the corners, and it supports soft growing parts. Sclerenchyma is dead, its walls uniformly thickened with lignin, and it supports permanently, as fibres or as sclereids.