ESSEX   BOTANY   AND   MYCOLOGY  GROUPS 

This is rather a distinctive fern, with long, delicate, brittle, blackish petioles giving rise to three more or less equal sized bipinnate segments that form the thin, vivid green, overall triangular tripartite blades, each segment  being unfurled early in the spring from a separate ball-shaped primordium in the young leaf. The sori are orbicular, naked, and arranged near the margin on the underside of the pinnules. The fronds arise singly quite a distance apart from a long, branched, creeping rhizome, and the three segments of the blade tend to droop downwards at an angle to the petiole. It is typicaly a fern of Oak-Birch woodland in the cooler and wetter parts of north and west Britain on deep acidic mineral soils and brown forest loams with a humus layer that stays wet all year but it also occurs in conifer plantations.  Elsewhere it turns up occasionally on damp walls, particularly on railway bridges, where the steam from trains probably kept it moist. There have been odd records from Norfolk, Suffolk, and Hertfordshire as well as Essex. Although some regard these occurrences as 'garden escapes' due to spores released in the vicinity, it is just, if not more than likely, that the tiny spores have been carried on the wind from across the North Sea. Although George Stacy Gibson cast doubt on the authenticity of the Chingford Church record, these other  records suggest it was more than likely correctly. No plants are known in the county at the present time.