27-4 THE JUSSIEUS AND THE NATURAL METHOD. 



more apparent and easy to be observed. It has been tbongbt that this double 

 object might be fulfilled by joining to the essential characters, which are sometimes 

 little apparent, certain accessory characters, which are constant and always visi- 

 ble, and which indicate the existence of the former by associating the corolla 

 with the stamens, in order to designate the classes." (Memoir of 1774.) 



Laurent lias since said, (1824:) "It wonld be necessary to adhere to this 

 number" (the number sevtm of Bernard,) "if, in order to avoid all exception or 

 variation, the classes could only be founded on invariable characters. But if it 

 be observed that the number of families now adopted amounts to nearly one 

 hundred and fifty, and is consequently quite considerable for each class, the 

 necessity will be felt of foraiing new subdivisions, without deviating, however, 

 from admitted principles, and by always adhering to characters of the greatest 

 value. That which first presents itself, after the invariable, is the character 

 derived from the mediate or immediate insertions, or, otherwise, from the corolla 

 considered as existent or null, as monopetalous or polypetalous. Although it be 

 subject to some variations, it is still that Avhich presents the fewest, and by 

 employing it for the subdivisions, the number of classes can be multiplied, which 

 diminishes embarrassment in the arrangement of families, and may much facili- 

 tate stiidy. It is true that this character is of no utility in dividing either the 

 acotyledons, the ilowers of which are too little apparent, or the three classes of 

 monocotyledons, in which the corolla does not exist, since the part which was 

 long taken for such is a true calyx. It is in the dicotyledons alone, then, that 

 we can employ the character of the insertions, whether mediate, simply immediate, 

 or essentially immediate ; or, in other terms more easily remembered, the character 

 of monopetalous, polypetalous, apetalous plants. We thus establish, though 

 admitting of some exceptions, in each of the three classes of dicotyledons, three 

 subdivisions, without deviating from the principles adopted, and the number of 

 dicotyledinous classes would then be raised to nine. Further, the subdivision 

 or class of monopetals with epigynic corolla, or corolla borne on the pistil, may be 

 separated into two, according to the character of their stamens, distinct in one 

 of its divisions, united in a sheath by the anthers in the other, which comprises 

 solely the great series of composite plants. This separation, which, in the 

 dicotyledons, adds a tenth class, does not separate families and conflicts with no 

 affinity." 



He afterwards adds : "It has already been stated that, in order to arrange the 

 families more easily, it was necessary to multiply the great divisions, always 

 adhering, however, to the most solid characters, and we have seen how it has 

 been practicable to augment this number of classes in the dicotyledons through 

 considerations derived from the corolla. It has appeared to us, nevertheless, that, 

 Avith a view to fiicility of study, an object which should not be neglected, it 

 was necessary, in oi'der to have in the great divisions principal characters easy 

 of apprehension, and to approximate a little in this point to the method of Tourne- 

 fort, founded on the corolla, to give the preference to mediate and immediate 

 insertions over hypogynic, perigynic and epigynic insertions, and not to follow 

 rigorously the first principles established. We shall have the same classes, but 

 presented, in the dicotyledons, according to another series. Thus, by leaving 

 the four classes of the first two giand divisions to subsist in their integrity, and 

 without any change, we shall, in the first place, distinguish the dicotyledons into 

 apetalous, monopetalous and polypetalous plants. In the apetalous, or those with 

 essentially immediate insertion, we shall distinguish three classes with epigynic, 

 perigynic, and hypogynic stamens. If we next pass to plants with a monopetalous 

 corolla or mediate insertion, and if we remember that the insertion of this corolla 

 then becomes the essential and primary character, we shall subdivide the mono- 

 petals into the hypogynic, perigynic and epigynic coi'ollas, and the epigynte will 

 be further divided into synantheraj, having united anthers, and chorisanthera}, 

 having distinct anthers. The polypetalous plants, or those having the insertion 



