Comparative Physiology. 201 



done by Lindley, Bentham, Brown, and others, to remedy these 

 defects, but much remains still to be done. Distinctions of 

 species are confined to superficial and external characters, the 

 higher structural characters being reserved for the higher divi- 

 sions, which are generally confined to fructification, though 

 sometimes very permanent characters are to be had from less 

 essential parts of the plant. Great experience and judgement, 

 and much reasoning from physiological knowledge, are requu-ed 

 in deciding what are permanent characters and what only trans- 

 itory ; and the want of attention to this has been the cause of 

 much confusion, both in species and genera. Much confusion 

 has arisen from the many ditFerent names given to the same 

 jilant, by selecting mere varieties as species ; by the splitting 

 of genera that might well have stood together, and uniting 

 others that had no call to be so. Undoubtedly many of the 

 changes are necessary; but they greatly tend to confusion, and 

 it would be well if botanists would attend to the rule laid down 

 by some of our most eminent scientific men, rather to j^ut up 

 with trifling inconveniences than to change without urgent 

 necessity can be pleaded. It would be well if, as in pronounc- 

 ing dictionaries, some preeminent authority could be decided on 

 to which all might bend. Much money has been lost needlessly 

 in purchasing what was before possessed, and the public are 

 getting tired of changes, unless good reason can be shown for 

 them, and a prospect of their being permanent. There is much 

 need for some energetic methodical mind, like that of Linngeus, 

 to bring order out of confusion. 



In the lowest groups of plants, as fungi, lichens, algse, &c., it 

 is not easy to define them, he says, by their structure. " Lichens, 

 if removed from light and over-supplied with moisture, have a 

 tendency to assume the appearance of algte. In such simple 

 forms of vegetation as Protoccocus nivalis (red snow), Palmella 

 cruenta (gory dew), and the nostoc or fallen star, there is only a 

 simple aggregation of vesicles without any definite arrangement ; 

 sometimes united, sometimes not, and by their rupture giving ex- 

 istence to the germs contained within. By some they have been 

 placed among algge, by others among fungi, by others among 

 lichens. In beings of such simplicity, there are no definite cha- 

 racters to determine their aflfinities." He next traces the ascent in 

 the scale of existence from minute fungi, as mould, mildew, &c., 

 in which the absorbent nutritive and reproductive functions ap- 

 pear confounded with each other, up through mushrooms, in which 

 a distinct stem is developed separating the pileus or cap, the 

 reproductive system from the nutritive of the root, showing 

 how a progressive complication of form arises without any al- 

 teration of the original characters of the simpler members of the 

 group, and conducts upward to the higher classes. The Cryp- 



