150 



(Baillon) ; aud lastlj to the Begouiacese'^ (Baillon) in tlie imisexiial flowers, 



iu tlie iuferior ovary, iu the eouuate stameus, iu the leaf - yeuatiou, iu th'3 



plficeuta aud iu the exalbuiniuous seeds. Auother iustauce of the trausitiou 



frovn the Parietales to the Metaclilamydese can be seen in the gamopetalous 



genera of the Theacsfe, such as Eurya aud Ameslea. Moreover, some couneo- 



tious may be fouud betweeu the Parietales aud the Ericales, when we compare 



the StachyuracesB^^ and Clethracese (Baillon). As is stated above, the relation 



of the Parietales iu oue point or another to other series is of wide extent, 



reaching from the SaKcales or the Centrosparmre fcir up to the Cucurbitales. 



At one time we consider their gamopetalous character, and place them iu the 



Metachlamydese. At another time their jjolypetalous geuera make them 



assiguable to the Archichlamydese. The systematic position of the series should, 



therefore, be dyuamic. As to the famiHes iu this series, it is absohitely 



impossible to arrange them serially, as they inter-relate one another hke the 



uiethes of a net. To this fkict, I shall retum later on. What Englee mentious, 



in this case, partly confirms the above statemeut. He says"*^ : — 



Eine solclie Eeihe wie die Farietales ist niclit ein einlieitliclier 

 monopliyletischer Verwandtschaf tskreis, sondern ein Coinplex von 

 mehreren Verwandtschaf tskreisen, die teilweise von verschiedenen 

 AnfangsiJiinkten ausgehend in ihrer Entwickelnng anf derselben 

 mori)hologischen Hauptstufe Halt gemacht haben, teilweise, wie die 

 TJnterreihe der Flacourtiineae noch verschiedene Hauj^tstTif en der 

 Entwickelung erkennen lassen. 



But, wheu this series had beeu described by Englek as a complex of mauy 



groups, how then is it possible to give it a fixed place? The auswer should 



decidedly be uegative. 



Next, in Englee's system foUow the Opuntiales*\ As has already beeu 



stated, they bear resemblance iu a greater or less degree to other series ; to 



the Eauales in the spiral arraugement of the floral elements, to the Paiietfdes 



iu the structure of the ovary, aud to the Ceutrospermse in the relative positiou 



of the sepals, petals aud stameus. Cousequently, their natm-al positiou changes 



from this place to that accordiug to the way iu which they are cousidered. 



1) NiWiht. Pfl.-fam. 111.-6, a, p. 133. 2) 1. c. 111.-6, p. 103. 



3) Enqlkb, A. — Erlauterungen, 1. c. p. 368. 



4) Engleb, A. — Erlautenmgen, 1. o. p. 369. 



