416 



and veins of leaves vary equally, and the one stated is taken about 

 the middle of the plant and the middle of the leaf. There are many 

 plants, the leaves and branches, or leaf-stalks, of which are triplicates, 

 such as trefoil, wood-sorrel, wild strawberry, wood anemone, Tussi- 

 lago, &c. Others, having whorled leaves, or the leaf rounded, present 

 a similar arrangement in the stemage, or an approach to it. Bed- 

 straw, field madder, corn spurry, &c., are examples of the first, and 

 geraniums, ranunculuses, the marsh-penny, the marsh -marigold, and 

 tormentil of the second. Stemless plants seem to be most difficult to 

 bring within the scope of the analogy in question ; and this, I think, 

 might easily be accounted for; but in the mean time I shall not 

 enlarge. 



Assuming the foregoing observations to have been accurately made, 

 it would appear that Dr. M'Cosh's views are borne out by Nature in a 

 very remarkable manner, and demand still further investigation. 

 Much, no doubt, remains to be done in the study of vegetable mor- 

 phology ; and it strikes me that this is an advance in the proper 

 direction. We find in plants divisions and subdivisions carried out 

 with surprising regularity, so as often to give the leaf, or leafage, a 

 form resembling that of the whole plant ; and we find, on measuring 

 these successive divisions, that equal angles have generally been 

 maintained throughout. Hence we can scarcely resist the conclusion 

 that a plant is a unity, all its parts being formed after the same model. 

 It is in strict uniformity with that beautiful connexion which subsists 

 between unity and diversity in the works of Nature, that there should 

 be fundamental forms in the vegetable as well as in the mineral king- 

 dom. Tn crystals we see variety produced by combinations of forms 

 which may all be referred to one in each crystal, as a base, or type ; 

 and still further, that the edges and faces of consecutive forms in these 

 combinations have equal angles ; and in vegetables, I conceive, we 

 may see the same, by modifications, in each of one fundamental form, 

 and that the leaf. May we not also see that the alternate process, by 

 which the face of one simple form of crystallization assumes the posi- 

 tion of the edge of another to which it is immediately related, is 

 represented in the ramification of a plant, and some of its peculiarities 

 marked by the measurement of the spiral thread ? Be this as it may, 

 an equality of angles does certainly predominate in the vegetable 

 kingdom ; and it may not be too fanciful to suppose that we shall yet 

 have a classification of vegetable forms similar to that of our systems 

 of crystallization, in which the normal angle will form a leading cha- 

 racteristic in the determination of species. 



