RANALES 413 



bisexuality, numerous appendages, spiral arrangement, actinomorphy, 

 absence of fusion, follicular carpels, and anatropous ovules. They are 

 advanced in the presence (in some genera) of unisexuality, few and 

 whorled organs, zygomorphy, connation, and achenes. The ovule also 

 shows strong specialization; the nucellus is absorbed before the flower 

 opens, and the embryo sac is enclosed by the inner integument. This 

 ovule structure is frequent in the Sympetalae but seems to be unknown 

 elsewhere in the Ranales, except in Nandina ( Berberidaceae ) . The 

 wood, except in Hydrastis, is advanced, having simply perforate vessel 

 elements. In the family, basically primitive, the advanced characters 

 are doubtless related to the dominance of high specialization in habit 

 - — herbs and vines. 



The family shows stages in the differentiation of a two-seriate peri- 

 anth, of reduction in number of carpels, of connation in the gynoecium, 

 of reduction of the follicle to the achene, with accompanying simplifica- 

 tion of the carpellary vascular system (Fig. 42), of reduction in num- 

 ber of ovules from many to one, in the development of anemophily. 

 The limitation of subfamilies has varied greatly, and Paeonia has been 

 removed from the family to form a separate family of the Dilleniales. 

 (A position beside the Dilleniaceae was long ago given it.) 



The series in specialization in the gynoecium is perhaps most marked, 

 with reduction in size and number of carpels, in number of ovules, and 

 with the beginning of connation. Cimicifuga and the closely related 

 Actaea show progressive reduction in carpel number — several to one 

 within the genus Cimicifuga and one in Actaea. Reduction in number 

 of ovules accompanies reduction in size of carpel; Anemone, Clematis, 

 PotentiUa (Fig. 42N), and Adonis show vestigial ovules at the top of 

 the ovary, and TroUius (Fig. 42B) shows remnants of the vascular 

 traces to lost distal ovules. The carpel of Hydrastis, with two ovules 

 only and one of these often abortive, is intermediate between the typical 

 follicle and typical achene (Fig. 42D). 



HeUeborus shows, in one species, connation of the carpels for half 

 their length, and Nigella shows, in its various species, progressive 

 stages in their union. The union of the carpels in Nigella has been in- 

 terpreted as apparent only, the result of the upgrowth of receptacular 

 tissue about the carpel bases, as occurs in Nelumbo, but no sound 

 anatomical or ontogenetic evidence supports this interpretation. 



The genus Hydrastis, the object of considerable attention by both 

 taxonomists and morphologists, has been variously placed within the 

 Ranunculaceae and in other families. It has been described as close to 

 Podophyllum in the Berberidaceae. Strong resemblance has been seen 

 to Paeonia, and it has been placed, with this genus, within the 

 Ranunculaceae, Suggestions have been made that it, like Paeonia, be 



