1898] THE GROUPS OF ANGIOSPERMS 347 
of the series are coordinate and not serial; that they stand side 
by side, but have not proceeded one from another. The Scyto- 
petalacee have a very uncertain position in the series. 
As already indicated, the Parietales reach back in their affini- 
ties through their simpler families to the region of the Ranales. 
The Dilleniaceze were also formerly reckoned with the Ranales, 
but they show affinities for the tropical families Eucryphiacee, 
Ochnacez, Caryocaracez, Marcgraviacee, Quiinacee, Theacez, 
Guttifere, and Dipterocarpacez, and I have brought them all 
together as a subseries, Theinew. Another subseries, the 
Tamaricinee, is made up of the Elatinacee, Tamaricacez, and 
Frankeniacez, which mostly inhabit temperate zones. The 
Fouquieriacez, which in the Pflanzenfamilien were reckoned with 
the Tamaricacez, are better separated as an independent family 
and subseries, on account of their gamopetalous corolla and oily 
albumen. The changes which have been made in this series are 
based chiefly upon the results obtained by Dr. Pritzel in his late 
studies of the seeds of Parietales. His data have great value in 
the determination of the genetic relationships. Such a series as 
the Parietales is not to be regarded asa single monophyletic circle 
* relationship, but as a complex of such circles, which, proceed- 
ing from various starting points, have either arrived in their 
*volution at the same morphological stage of advancement, Or, 
Tike the subseries Flacourtiinez, still show various stages of 
4 ; development. : 
The Opuntiales, with their spiral floral arrangement and 
. ag Ee pracle which encloses the syncarpous cine ne 
little eg a primitive floral type, essentially departing ai 
a ae that of many Nymphezacez. The only reasons 
Pacing this series next the Parietales is that free carpels never 
) itin the Cactacez, that the placentz are parietal, and the 
Styles are united. 
a i. the series Myrtiflore and Umbelliflore the tie 
|. alae within the receptacle has become : zs 2a 
aco st to the preceding series, the arrangemen ee 
oe nstantly cyclic. In the Myrtiflore perigynous an epigy 
ment 
and, 
