no 
ON THE SMALLER SPECIES OF ALGH5 OR FLAGS. 
This plant, as well as the Palmella cruenta, or gory-dew, Lepraria 
kermesina , or bloody rain, with many others called reeks, or earth- 
sweats, as well as certain minute animalculee, will sometimes suddenly 
appear in such great abundance, as even to tinge pools of water with 
the hue of blood, to make red stains on the sea shore, and to discolour 
considerable tracts of ground, so as to simulate red snow, or dew, 
or rain ; and such in fact the appearance is vulgarly supposed to be. 
These occurrences are often regarded by the ignorant as of sinister 
omen ; indeed whole towns have been occasionally alarmed with the 
report, that, in the course of a single night, the water of their pools 
had become changed to blood ; and the dismay was not relieved until a 
philosopher exhibited to the eyes of many, the minute corpuscles which 
had wrought the change of hue, and which were easily separable by 
filtering the fluid. 
Palmella cruenta, or gory dew, is common in many places; I found 
it abundantly, during 1831 and 1832, at Oxford; and it is frequently 
observed in damp situations, forming broad indeterminate patches, of a 
deep rich purple, with a shining surface, as if blood or red wine had 
been poured over the stone or ground. During dry weather it con¬ 
tracts, grows dull, and disappears: but after rain spreads anew, 
resumes its sanguine colour, and becomes conspicuous even to the most 
incurious eye. Its history affords (says Johnson) an easy explanation 
of a phenomenon considered supernatural by monkish chroniclers, and 
to which Drayton, in his notes to Poly-Olbion, refers. “ In the plain near 
Hastings, where the Norman William, after his victory, found King 
Harold slain, he built Battle Abbey, which at last grew to a populous 
town. Thereabout is a place, which, after rain, always looks red, 
which some have attributed to a very bloody sweat of the earth, as 
crying to heaven for revenge of so great a slaughter.” 
But not only have we, at times, showers of the so-called red or bloody 
snow, rain, &c., and gory dew, ice, and so forth, produced as above 
explained, but occasionally these storms and dews are found of different 
colours, as green, blue, and yellow. These analogous phenomena are 
owing to plants not very different in their nature: the blue to Byssus 
cobaltiginea, the green to Palmella holryoides , and the yellow to 
Lepraria candelaris, or chlorina. 
Besides the gory dew, Palmella cruenta, which is similar in its 
structure to the red snow plant, other low vegetable productions have 
been noticed by different authors, as possessing a similar colour; such 
are the Lepraria kermesina, which, by the way, is considered only 
a particular state of the red snow plant itself, and the Byssus cobalti¬ 
ginea . These are always found in situations in which they are exposed 
