INTRODUCTION. 



RULES FOR INVESTIGATION. 



WHEN a plant offers itself to our investigation, the first 

 thing to be determined is, the class to which it belongs. 

 This is to be done by observing the number of stamina, and 

 referring to the preceding Tables of the Classes. Should 

 there be a difficulty in ascertaining the number of stamina, 

 on account of the number appearing different in different 

 flowers, though belonging to the same plant, it is advisable to 

 examine one or more of the flowers which are yet unopened ; 

 for the antherse are in that state more distinct, and we may 

 be certain that none of them have been lost. Having fixed 

 upon the class, we must again refer to the preceding Tables, 

 where we shall find of how many orders the class consists ; 

 and, after observing the circumstances of the pistilla, or 

 other characters by which the orders are determined, we must 

 compare these, and we shall readily discover the class and 

 order to which it systematically belongs. 



If the order we refer it to has any subdivisions, we shall 

 soon perceive under which of the subdivisions the genus 

 should be found : and as this Dictionary presents the student 

 with the characteristics of the orders and their respective 

 subdivisions, and also with the genera belonging to each 

 order or subdivision alphabetically arranged, after having 

 discovered the class by the assistance of the preceding ana- 

 lysis, he will easily ascertain the order in this table under the 

 class to which it belongs, and will there find himself at once 

 referred to the genera and species in the body of the work. 



After comparing the flowers with the characters of the 

 different genera contained in the order, or in the particular 

 subdivision of the order, it will soon be seen with which of 

 them it best corresponds ; and if any one agree pretty exactly 

 with our specimen in all the leading characters, we are then 

 certain of the genus. Doubtful matters will sometimes arise; 

 but these are for the most part made clear, by observations 

 subjoined to the generic descriptions. In consulting these 

 generic descriptions, the learner is advised to pay particular 

 attention to the structure of the pistil, and especially to that of 

 its germen, when it begins to ripen into a seed-vessel ; because 

 these parts being most essential to the continuation of the 

 species, are less liable to variation, than those which are 

 less important. 



If none of the generic characters at the beginning of the 

 class agree with the flower, we must then look at the end or 

 subdivision of the order to which it was referred, and see 

 what plants are there mentioned. If we have not found the 

 plant before, it must be some one of these ; looking therefore 

 for these, and comparing the generic descriptions with the 

 specimen in hand, we shall not only discover the genus, but 

 the circumstance which produced our perplexity. 



The young student is also recommended to practise the 

 investigation of genera only, for a considerable time, before 

 he attempts to ascertain a species; and when by this means 

 he has attained a pretty accurate knowledge of classes and 

 orders ; also of the parts composing a flower, and its sub- 

 sequent state of fruit, or fructification, and likewise with the 

 terms employed in describing them; he may next proceed to 

 determine the species and varieties. 



Whenever the species are numerous, they are subdivided. 

 Consider with which of these subdivisions it agrees; and 

 having determined that, compare it with the several specific 

 characters, as it will probably agree with some one of these. 

 If you are still in doubt, guided by the references to figures 

 which commonly follow the specific character, turn to such 

 figures as you possess ; and to make the point still more cer- 

 tain, compare your plant with the descriptions which follow 

 the references to figures ; for these will remove many an 

 existing doubt, and obviate many a possible mistake. If the 

 plant in question be any remarkable variety, you will pro- 

 bably find it introduced after the additional descriptions above 

 alluded to. 



Make it an invariable rule, not to pass over a single term, 

 the precise meaning of which you do not thoroughly under- 

 stand : always consult the Botanical Dictionary, at the end 

 of this Introduction, which will soon remove the necessity of 

 consulting it at all. 



Lastly ; When gathering plants for examination, collect a 

 considerable number of the flowers, and, if possible, some 

 just opening, others fully expanded, and others with the seed- 

 vessels almost ripe : take care also to gather one specimen of 

 the plant, at least, as perfect and entire as possible. 



It is deemed necessary to subjoin various examples for 

 investigation : the student will, however, do well, after exa- 

 mining', to try his strength by examining any unknown flowers 

 he may pick up in his walks. 



EXAMPLES. 

 COMMON PRIVET. Ligustrum Vulgare. 



This shrub is found in hedges and shrubberies in many parts 

 of England. It generally blossoms in June, and its blossoms 

 are white. Having obtained a branch of it in blossom, we 

 proceed to investigate it ; and looking into several blossoms, 

 find two stamina in each, by which we know it belongs to 

 the Diandria class. This class contains three orders, which 

 depend upon the number of pistilla ; looking again at the 

 flowers, we discover one pistil in each : so that the plant 

 evidently belongs to the order Monogynia. This order is 

 subdivided into several parts ; and observing the marks of 

 these subdivisions, we find that in our specimen the blossom 

 is formed of one regular corolla, fixed beneath the germen; 

 which corresponds with the first subdivision, and that con- 

 tains only one English genus, so that there can be no doubt 

 but the plant is a Ligustrum. We shall also find that the 

 blossom is cloven into four parts, and that it is succeeded by 

 a berry containing four seeds. Referring to the genus Ligus- 

 trum, and comparing it with the generic description, we have 

 the satisfaction to perceive a perfect coincidence. Having 

 ascertained the genus, we proceed to discover the species ; 

 and as there are only two species of that genus, we know the 

 shrub in question, from its lanceolate leaves, must be the 

 common Privet, or Ligustrum Vulgare of Linneus. 



