October Gallery

Hardknott Roman Fort EAW589036

HARDKNOTT, Cumbria. Aerial photograph showing the well-placed Roman fort on a promontory overlooking the Lake District (NGR: NY218015). Aerofilms Collection (see Links)

© Historic England

Aerial, Fortification, Landscape, Moor Land, Mountain, Roman, Rural

LM of biogenic silica in horsetail

Light micrograph of a section of the horsetail Equisetum arvensis showing internal deposits of silica (the yellow features). This biogenic silica is taken up in solution from the surrounding soil and then distributed throughout the plant, in sites such as the cell walls, in amorphous (non- crystalline) form. Its function may be to provide structural support since the cell walls of this primitive plant are quite thin and non-lignified. If the soft tissues are removed using acid then a fragile, skeletal structure of silica remains virtually intact. The plant used to be called scouring rush because of the abrasive qualities of its fibres. Magnification: x400 at 35mm size

© POWER AND SYRED/SCIENCE PHOTO LIBRARY

LM of the diatom Pinnularia nobilis

Light micrograph of the diatom Pinnularia nobilis (centre), surrounded by other assorted diatoms. The diatoms are a distinctive group of single- celled algae containing about 10, 000 species. They form an important part of the plankton at the base of the marine and freshwater food chains. The characteristic feature of diatoms is their intricately patterned, glass-like cell wall, or frustule. The frustule consists of 2 halves which fit together like the lid & bottom of a box. It is often decorated with rows of tiny holes, known as striae, which are arranged either radially or on the 2 sides of a central axis. Magnification: x400 at 35mm size

© POWER AND SYRED/SCIENCE PHOTO LIBRARY