INTRODUCTION. 343 
posing his tribe of Artemisiacee to include Ambrosiee and 
exclude Tanacetex, a tribe which he characterizes as irrefutably 
natural, it appears to me that by relying for it solely on one 
character (the anemophilous fertilization) his classification becomes 
as artificial as when Linneus relies solely on the repartition of 
the sexes, Lessing on the shape of the style-branches, Schultz 
Bipontinus on the shape of the achene, or others on the pappus 
alone. As to his idea that heterogamous capitula with fertile 
female ray-florets and sterile disk-florets may be regarded as simple 
hermaphrodite proterogynous flowers descended from inflores- 
cences of proterandrous flowers, this is surely but little more than 
a play upon words. 
With regard to the part I have myself taken in the elaboration 
of this great order, I may observe that, long before I was called 
upon to undertake it for our ‘Genera Plantarum,’ I had had 
repeated occasion to test the value of the labours of my prede- 
cessors, and for various publications had examined in detail the 
Composite of Europe, of British Guiana, of tropical Africa, of 
China and allied Indian forms, and especially of Australia; and I 
have now, with the aid of the rich stores and extensive library 
collected together at Kew, and liberal assistance in the way of 
loan of specimens or notes on typical specimens in Continental 
herbaria, communicated by my friends M. Decaisne and M. 
Cosson of Paris, Dr. Ascherson of Berlin, and Dr. Fenzl of 
Vienna, been enabled to examine specimens and compare the 
original descriptions of an immense majority of the published 
genera, subgenera, or sections, as well as of numerous species which 
have been supposed to present some anomaly, or which by their 
aspect seemed to suggest some peculiarities which might affect 
the genericcharacter. Notwithstanding, however, the lengthened 
period which I have devoted to this tedious labour, I feel that 
there is yet much left to be done to future synantherologists who 
can undertake throughout a specific monograph, such as I have 
only been able to do with regard to the Composite of some 
countries or of a limited number of genera. There are also cer- 
tain characters, and some of them evidently important, which our 
herbarium specimens often do not supply. Perfectly ripe achenes 
are often wanting in whole genera; and microscopical characters, 
such as the form of the pollen, upon which much stress has been 
laid of late years, have been observed in too small a number of 
species to ascertain their real connexion with general affinity. In 
LINN, JOURN.—BOTANY, VOL. XIII. 20 
