68 J. SAUNDERS — NOTES ON THE MYCETOZOA. 



Plasmodium is sometimes found to have stained crimson the wood 

 on which it grows. Quite recently Mr. C. Crouch observed in Silsoe 

 Park, Beds, a mass of it, several inches square, which was visible 

 more than fifty yards away. The sporangia are compacted into 

 masses which vary in size from that of a pea to that of a hazel-nut, 

 and they may often be seen in groups on fallen logs in early spring. 

 The species is not uncommon in such places as Shcrrards Wood, 

 near Welwyn, and in the valley of the Ver, near Eedbourn. 



A rare species, which has a deep crimson plasmodium, is Clathro- 

 ptychmm rugulosum. This is less reserved in its habits than is 

 Lycogala epidendrum^ and it creeps about on the surface of decayed 

 willow logs which are shaded by vegetation, 



Brefcldia maxima should be sought for in moist hollows near 

 streams and springs where decayed logs are to be found. The plas- 

 modium is opaque white, and about the thickness of cream. It creeps 

 about in the decayed vegetation near a rotten log for some ti,me, 

 and then spreads itself over the wood in a beautiful creamy-looking 

 mass. When matured the aggregated sporangia (sethalium) become 

 of a purplish black colour, 



Crihraria argillacea has plasmodium of a dull leaden hue when 

 rising to maturity, and is usually found on decayed conifers. 



Didymium squamulosum is a very abundant species, growing in 

 such places as damp ditches where leaves have acci:mulated, and in 

 boggy spots under the shade of trees. Its plasmodium is of a dirty 

 white colour, and in creeping over dead foliage it leaves a number 

 of vein-like tracks behind. One is enabled sometimes to assume 

 its proximity fi'om the traces it has left. It is plentiful in the 

 valley of the Ver, near Redbourn. Didymium farinaceimi occurs 

 amongst dead leaves and twigs which have accumulated in moist 

 situations. The plasmodium is grey, its dusky hue being probably 

 partly due to the ingested particles of decayed foliage on which it 

 feeds. At least we find that some species with a similar habit, 

 such as Craterium indgare, have this peculiarity, and also have the 

 power of cleansing themselves from the refuse material, becoming 

 lighter and clearer in colour just prior to the fruiting stage. 



Most of the Physarefe have a greyish-white or dirty grey 

 Plasmodium. Tliat of Fhysarum leucophaiun is with difficulty 

 distinguished when attached to the bark of oak. That of 

 P. leucopua is dirty grey in a natural state, but under cultivation 

 it becomes lighter, and sometimes shows a beautiful network of 

 veins, appearing almost white when on a dark background. The 

 Plasmodia of Physarum, Craterium, and Badhamia agree in the 

 habit of progressing by throwing out fan-shaped processes or veins, 

 often of the most intricate patterns. (See Plate V.) If they do 

 not find food, or if their surroundings are not favourable to further 

 progress, they have the power of retracting and condensing them- 

 selves into a small compass, thus assuming a resting stage until the 

 recurrence of congenial conditions. 



Fhysarum citrinum., a handsome species very rarely found in 

 Eritain, has recently been detected in considerable quantity in a 



