Oxford University Cave Club

The Flora of Cueva de Valporquero

S.F. MacPherson Stewart

The flora of the Spanish caves is sparse, but it is much more abundant than that :of the British caves.

The flora consists of liverworts, and mosses at the entrance, and further in are the fungi; the study was made of the fungi only. The conditions of humidity, and temperature within the cave, are ideal for the growth of fungi. The spores are brought in by air currents, flowing water, or on the bodies of animals, even on the muddy overalls of cavers! On reaching a suitable substrate (organic material or mud) the spores germinate. However, due to the lack of light there is often malformation of the fungus: the fruiting-bodies do not form or are sterile, so often any means of identification is lost, since one of the first criteria of identification is the form and or colour of the spores. Again the colour of the fruiting is often lost or altered, and in some cases there is a form of etiolation, which points to the fact that the fruiting body is in some cases positively phototropic; but in other cases there is no etiolation but the fruiting-body is still vertical, even when on a slope, so it is probably negatively geotropic. The area of differential growth is just below the pileus.

If sporulation docs occur, the air around the fruiting-body becomes filled with spores, and there is a greater infection of the area.

A fungus known by the Spaniards as "old man's beard" was found on rotting wood, and is obviously a member of the Mucorales since it is a brown mycelium, with sporangia (asexual reproduction), but no zygospores were found (sexual reproduction). The sporangia contained black spores.

One Boletus* was found with pale yellow-brown mottled pileus; however no spores were found. Coprinus** species were evident in many areas of the cave, and point to reinfection of the vicinity by spores from fruiting-bodies already in the cave. There was one Polyporus or "bracket fungus"*** on a wooden balustrade in the old part of the show cave. Penicillium spinulosum was found on the clay covering some of the walls. It was found only where there was free water; therefore there must be some other water requirement than maximum humidity, but this will have to be examined further.

With a bit more investigation a much clearer idea of the floral populations of caves could be found, and the problems involved in identification could be seen in prospective. Anyone with the slightest interest in botany is urged to do some collecting and identification, the techniques of which are very quickly learnt. The populations are small in any one cave, but a large catalogue could eventually be made.