130 OF THE FUNGI. 



clean through cork and leaf, sections of the required thin- 

 ness may be obtained without difficulty. To keep the 

 two pieces of cork from shifting during the operation, they 

 may be thrust through a metal ring of suitable size, or a 

 piece of stout paper may be gummed round them ; a still 

 simpler plan is to tie them together with strong thread or 

 thin string. The section can be placed at once on a slide 

 with a fine hair pencil. 



In a large number of cases the fruit must be examined 

 in a dry state, in order to ascertain the true connection of 

 the spores with their receptacles, as water causes them to 

 separate. Of this description is the whole order of Botry- 

 taceae or Hyphomycetes — an order which embraces most of 

 the common \ moulds, ' growing upon organic substances, 

 both dead and living ; the Peronospora of the potato, to 

 which I lately alluded ; the parasites which infest the 

 onion, pea, rose, and clover, and numerous other pests of 

 the farm and garden. In all these (which to the naked 

 eye appear as patches of a white woolly substance) the 

 fruit, or acrospores, as they are called in technical lan- 

 guage, are situated on the tips of certain upright threads, 

 sometimes solitary, but more generally branched, so as to 

 have the appearance of miniature forest trees, only that 

 there are no leaves, and that each branchlet supports at its 

 apex a single round or oval acrospore. In some cases the 

 branchlet itself is moniliform, or made up of rows of these 

 tiny reproductive organs, adhering end to end. 



From some unknown cause, the ' pedicels ' no sooner 

 . come in contact with water, than they ' lose their heads ; ' 

 the fruit drops off, and the observer misses the chance of 

 ascertaining the way in which pedicel and acrospore were 

 united. If then a fluid is applied at all, a single drop 

 must be laid on the slide after the specimen has been placed 

 ready for examination. Let the water touch the covering 

 glass, and it will creep under by capillary attraction and 

 saturate the object. 



