4 A DISCOURSE 



INTROD. cere of stature ; that are thick and solid, and stiffly adhere to the ground 

 on which they stand These we shall divide into the greater and more 



^ A Tree is defined to be a perennial plant, which rises to a very great height, with a 

 simple, woody, and durable Stem, or Trunk. By these characters Trees are distinguished, 

 with gi'eat accuracy, from Herbs, whose stems are frequently compound, herbaceous, or 

 succulent, and die down to the root every year. It is evident from the characters just 

 enumerated, that all trees are perennial. Herbs are either annual, that is, of one year's 

 duration ; or biennial, of two : those only are perennial, whose roots, not perishing with 

 the stems, continue a long time under the surface of the ground, and put forth a new stem 

 every yeai*. Upon these obvious and striking differences was founded the very ancient 

 division of vegetables into herbs and trees; though, perhaps, that distinction was princi- 

 pally suggested by the difference of size and duration of the plants in question. Be that 

 as it may, the division has been esteemed so natural and spontaneous, that, from the time 

 of Aristotle and Theophrastus to the present age, it has obtained a principal place in 

 almost every system, except that of Linnaeus, which mixes herbs, shrubs, and trees pro- 

 miscuously together. But this is evidently to preserve the harmony of his system, which 

 is solely founded on the fructification of every individual Genus and Species. We may 

 therefore easily discover the reason of Linnaeus's overlooking every other idea that did not 

 fall in with his own, and of his affirming, that, in this particular, Nature has put no limits 

 between trees and shrubs. Among the celebrated names in botany, which have retained 

 the ancient distinction, are numbered Casalpinus, the Father of Systematic Botany ; Morison, 

 Hermannus, Christopher Knaut, Boerhaave, Ray, Pontedera, and Tournefort. The 

 latter, rather than admit a division, through custom become necessary, chose to hurt the 

 elegance and uniformity of his plan ,• and, in fact, spun out into twenty-two classes, what, 

 without such division, might have been easily comprised in seventeen. On the opposite 

 side are ranged Rivinus, Christian Knaut, Linnaeus, Ludwig, and other names of less note. 

 The distinction into Trees and Shrubs, thougii of equal antiquity, is neither so obvious, 

 nor are its limits so accurately ascertained. In fact, of the numerous characteristic dif- 

 ferences which have been suggested by botanical writers, not one is perfectly satisfactory. 

 To say with Tournefort, that trees are universally taller than shrubs, is, in effect, saying 

 nothing, unless a certain fixed, immutable standard were previously established. Besides, 

 every thing respecting dimension is so variable in its nature, and depends so much upon 

 difference of climate, soil, and management, that were a standard of this kind attempted 

 to be established, the greatest confusion would ensue ; and the same plant in different 

 countries, and even, in opposite soils in the same country, would receive different appel- 

 lations, according as it exceeded, or came short of the given standard. Thus the ricinus, 

 or palma Christi ; the dwarf rosebay, rhododendron ; the strawberry-tree, arhutus ; and several 

 others, which grow to the size of very large trees in warm climates, are, in this country, 

 equalled and even exceeded in height by many of our smallest shrubs. The difference of 

 soil and culture in the same climate, produces a like diversity in dimension. Thus, to 

 take an example from herbaceous vegetables, the marigold, which, in a fat and moist 



