COMPOSITAE OF PERAUSTRAL AMERICA, 151 



carry special cultures for the purpose of testing this form, but 

 made notes upon it in its wild state near Hilversum, and in the 

 cultures of his collection. At the Xew York Botanical Garden, 

 the pure seed of unfasciated Oenoihevas was as prolific in fascia- 

 tion as the seed of fasciated individuals. Many of the groups of 

 plants also in the large general collection showed it, and it was 

 found in the purest strains of normal heritage. In all these 

 cases its appearance w^as due to the insects, and the malformation 

 was stimulated through their agency. 



The insect is but indirectly the cause of such curious anoma- 

 lies and their physiology belongs to the category of striking and 

 interesting traimiatic phenomena. ]\Ialformations involving 

 change of leaf arrangement, increase in the nundier of parts, and 

 secondary histological differentiation are numerous in the annals 

 of teratology, and the study of the relation of insects to abnoruuil 

 growths of all kinds luav lie said as vet to be scarcely begun. 



THE COMPOSIT.E OF PERAUSTRAL A]\IERICA. 



By Professor George Macloskie. 



George Benthaui's Survey of the Compositse (in the Journal 

 of flie Linnaean Socicly. 1873) has been our chief helj) on this 

 subject. He gives his idea of what the Com]>ositic are, having 

 superior, sympetalous flowers, 5-nierous, save that the gynecium 

 is primitively 2-merous, and is subsequently reduced to an 

 achene witli a single erect seed, devoid of endosperm. A crowd 

 of such flowers are cond)ined into a larger unity, or compound 

 flower head, having a conunon receptacle, and a common invo- 

 lucre ; so that the head of flowers has the appearance of a single 

 more complex flower. Tliis "compounding" has resulted in the 

 reduction of particular parts of the flowers thus aggregated, the 

 anthers coalescing, and the corollas diminished in size, the calyx 

 very much diminished and altered into a pappus, or completely 

 suppressed ; the bracts altered into the chaft' of the rece]itacle, or 

 the scales of the involucre. And sometimes thert is a scxnal 

 dimorphism by the abortion of the ovules or of th-^ antl oi-s in 



