HOOKER. — BOTANICAL INSTRUCTIONS. 03 



grasses and sedges which resemble one another so much, and to 

 secure both sexes of the willows. 



Selected specimens of extreme forms and varieties of species 

 should be sedulously collected, in order to show the limits of 

 variation in a given area, and all circumstances that seem to 

 influence variation should be noted. 



Any modification of the fades of the vegetation in the 

 various localities should be noted, as also the relative abundance 

 and variety of the ubiquitous as well as of the scarcer species, 

 their luxuriance of growth, &c. 



Soil collected on icebergs, or on transported masses of ice, 

 should be searched for seeds, roots, and remains of plants, and if 

 practicable spread out and kept moist, till any seeds it may contain 

 should have germinated. The number of kinds that germinate 

 under such circumstances should be noted. 



Mosses and HEPATiciE. 



These have never been collected with the care they deserve in 

 the Ai'ctic regions. They are much more numerous than a casual 

 observer, or one who attends to flowering plants only, would sup- 

 pose, and can only be satisfactorily collected by close attention. 

 Not unfrequently several species grow together in one tuft, and 

 the hepaticse especially are often found threading the tufts of 

 mosses as solitary individuals. When collected, the tufts, if they 

 have to be carried far, should be wrapped singly in paper, as their 

 leaves and organs of fructification are liable to be injured. To 

 preserve them the tufts should be broken up by the hand into 

 fan-shaped specimens and pressed; such specimens indicate the 

 habit of growth ; one tuft will thus supply many ipstructive 

 specimens. In the case of mosses in fruit, the calyptra and oper- 

 culum should be carefully sought for, and if fugacious put in a 

 little fold of white paper by the specimen. The male organs 

 are often minute and obscure, and should be diligently sought for, 

 using the pocket lens in the field if necessary. Many species 

 have the sexes in different tufts ; and in the Arctic regions the 

 male plants are probably more frequent than the female. Of some 

 species indeed the male inflorescence is only known. 



Lichens. 



These have not been collected with any method in the Polar 

 American Islands or in the high latitudes of Greenland. Many 

 of the larger species that grow on rocks or on the earth have 

 indeed been brought home, especially by Lyall and Walker, but of 

 the minute kinds that inhabit the bark of shrubs, and possibly the 

 leaves of various plants in those regions little is known ; nor of 

 the crustaceous kinds that adhere to stones, and which cannot be 

 removed without pieces of the rock or stone on which they grow. 

 To remove them a hammer and a chisel are necessary, and the 

 specimens should be trimmed so as to take as little bulk as possible, 



