32 EXPLANATION OF THE CLASSES 



delphous character of this tribe is sometimes quite 

 ambiguous ; the united filaments are commonly nine 

 out of ten, the whole number ; but there are, as in the 

 broom (Spartium), some papilionaceous flowers with 

 all the ten filaments united ; and only the curious gen- 

 era Sesbania, and sensitive Smithia in which the ten 

 filaments are united in two equal numbers. 



In the eighteenth class of Linnoeus (by many justly 

 abolished and added to Polyandria), there are three 

 or more bundles of stamens, more or less united at the 

 base, and it is hence termed Pol\adelphia (or many 

 brotherhoods). In St. John's wort [Hypericum) there 

 are species with the filaments in bundles, and others 

 with the stamens simply Polyandrous. In the beauti- 

 ful examples of Melaleuca, this character can be noth- 

 ing more than generic ; as it is, in fact, the principal 

 distinction which separates it from the Icosandrous 

 M.etrosideros. 



The next class, called Syngenesia (in allusion to 

 the peculiar union of the anthers), is perfectly natural, 

 and one with which you are acquainted as the com- 

 pound flowers. In the examination of the Thistle, the 

 Artichoke, and the Sunflower, you will be at no loss 

 to perceive the double character of this class. The 

 apparent flowers, or rather heads, being always form- 

 ed by the aggregation of several, sometimes some hun- 

 dreds of lesser flowers, hence called jlosculi or florets, 

 which in themselves are peculiarly distinguished by 

 having the anthers (always four or five) united into a 

 minute cylinder, but distinguishable as the parts of so 

 many distinct stamens by the disunion of the filaments 

 that rest upon the small corolla. 



In the class Gynandria, the 20th of Linnaeus, there 

 is a singular union of the stamen and pistillum, suffi- 

 ciently remarkable among the natural tribe of Orchi- 

 deous plants, in which the pollen, or fertilizing pow- 



