Ranales , Rhoeadales, and Rosales . 707 
Adonis annua . The seedling anatomy is of the ordinary type, but the 
doubleness is more marked in the cotyledon than in many of the Ranuncu- 
laceous forms. 
Myosurus minimus , although absurdly reduced, seems to form its 
minute diarch root in the usual way. 
Helleboreae. 
Nigella aristata and N. hispanica . The hypocotyl has the usual four 
phloem groups, with the four metaxylems connected in the cotyledonary 
plane by a thin bridge of crushed protoxylem. At the node the xylern 
and two phloem groups pass out to form the double bundle of the cotyledon, 
which gives off laterals at this point. Further down the hypocotyl the 
fusion of the phloem groups and approximation of metaxylem to form 
a plate results in the usual diarch root. 
Nigella sativa , described by Gerard, 1 and N. damascena , described by 
Chauveaud, appear to resemble the above species. 
Helleboriis foetidus shows similar features. 
Aquilegia vulgaris , A. alpina , and A. canadensis . This genus very 
closely resembles Thalictrum , and has the same histological peculiarities. 
The transition features seem to be quite normal, but the seedlings examined 
were rather old. As in Thalictrum , the cotyledonary bundle 
is markedly double. 
Delphinium for mo sum, D. luzulinum , and D. sp. (annual 
form). The seedling anatomy is quite normal. The double 
bundle is extremely marked, and the genus resembles Aqui- 
legia even in some of the histological details. 
Trollius asiaticus and Caltha palustris. These species 
conform in some measure to the general type, but present 
special features which will be dealt with in a subsequent paper. 
Paeonieae. 
Paeo7tia herhacea and P. arbor ea show two Y-shaped 
xylem groups in the cotyledonary plane of the hypocotyl, 
alternating with two extended phloem groups in the hypo- 
cotyledonary plane, which, in combination with the lateral Text-fig. 15. 
Paeoma herb deed » 
extension of the xylem arms, is slightly suggestive of the | n at. size, 
tetrarch condition. At the node the half of each phloem 
group passes out with a xylem Y into each cotyledon, where they form 
a large extended double bundle, which in P. arbor ea gives off laterals at 
the base of the petiole. When the strands are followed downwards, it is 
seen that as the diarch root structure is attained by aggregation of phloem 
1 Loc. cit. 
3 B 
