10 



should be taken to preserve a portion at least of the external contour 

 of the thallus, so as to know whether it is uniform or effigurate. The 

 earth specimens should be reduced in thickness while moist, and a 

 thin solution of mucilage applied on the under side, suflScient to sat- 

 urate the earth, but without coming through to the upper side. 

 When this is dry the specimen will be hard as stone and in no dan- 

 ger of crumbling. The specimens should be cleaned of dirt and 

 extraneous matter as much as possible without injury. "When all 

 these operations are completed the plants will be ready for the 

 herbarium. 



The methods of mounting for final preservation will vary with the 

 taste of the collector, the extent of his collection, and the space at 

 his disposal. Some prefer to place the sjpecimens in paper wrap- 

 pers ; others to mount them on paper. In a small collection, and 

 one in which it is desired to make a show of the specimens, the latter 

 is preferable. Nice white paper should be selected, of which it will 

 be well to have two sizes, one for the large Lichens and the other 

 for small ones. Lichens become brittle with age, and are therefore 

 not so likely to get broken when firmly attached to paper. The 

 plants should be perfectly dry when mounted, as if damp they will 

 contract in drying and curl the paper. It is well to attach them first 

 at the centre, and when they have become dry to fasten them at the 

 edges. As the features of the lower side are often important, two 

 specimens of each species should be mounted, so as to exhibit both 

 sides. Some lichens, like the Caliciums, are diflScult to preserve. 

 These may be softened by moisture and gently pressed till dry, so 

 as somewhat to depress the stipes, and they may then be placed in 

 envelopes, or, if space is not a consideration, in boxes. On the 

 wrappers or on the paper on which the specimen is mounted should 

 be a written or printed label, giving the name of the species, the 

 time and place of collection, a note of any peculiar features, especi- 

 ally of the internal ones of the thallus or fruit, which may have been 

 observed with the microscope, and a sketch of the spores and note of 

 their dimensions. As the proper way of mentioning the name of 

 the autljor of a species seems not to be always understood, it may 

 be well to note it here. "Where a writer is the author of a species 

 which has been referred to but one genus, his name, or an abbrevi- 

 ation of it, follows the name of the species, thus, " Roccella Leuco- 

 phsea, Tuckerm." But if the plant was at first referred to one genus 



