i 74 d e Fraine .— The Seedling Structure of certain Cactaccae. 
6 . The epicotyledonary vascular tissue plays no essential part in the 
transition-phenomena in any of the species examined except Mamittaria 
pnsilla , in which seedling no cotyledons are present ; it is, however, differ¬ 
entiated very early, especially in the Mamillarias, and supplements the 
existing vascular supply. 
7. There are differences in the method of transition between seedlings 
of the same species, in the case of Opuntia strict a, Ecliinopsis multiplex , 
Mamittaria rhodantha and M. pentacantha. 
8. The two £ double ’ bundles of the hypocotyl show a very great 
variation in their method of formation. They may arise :— 
( a ) By the bifurcation of the cotyledonary bundle, e.g. Ecliinopsis 
multiplex, Opuntia sp ., &c. 
( b) By the fusion of separate vascular strands. The strands which 
fuse may be :— 
(1) The two separate bundles present in the cotyledon, e.g. 
Ecliinopsis Lager mannii, Cereusperuvianas and Echinocereus 
Ehrenbergii. 
(2) The cotyledon-bundle and its tubercle-bundle, e. g. Echinocactus 
Ottonis, Series 3, Mamillaria multiceps and M. centricirrha. 
(3) The fusion product of a cotyledon- and a tubercle-bundle to 
form one half of the 4 double * bundle, the other half being 
produced by another similar fusion, e.g. Echinocactus Ottonis, 
Series 1. 
(4) The fusion product of a cotyledon- and a tubercle-bundle to 
form one half of the ‘ double ’ bundle, the other half being 
produced by the fusion of two cotyledon-strands, e.g. 
Ecliinopsis tubiflora. 
(5) The epicotyledonary bundles, e.g. Mamillariapusilla. 
9. 4 Barrel ’ tracheides are present in the hypocotyl and root of Opuntia 
stricta, O. maculacanthay Cereus tortuosus, C. peruvianas, Ecliinopsis 
multiplex, E. tubiflora, E. Lagermannii , Echinocactus Ottonis, and all the 
species of Mamillaria examined. 
Root. 
10. A tetrarch root is characteristic of Pereskia n. sp., the Opuntias , 
Nopalea n. sp., Echinocactus hexaedrophorus, E. denudatus and Mamillaria 
mis sour iensis. 
A c Cereus ’ type of arrangement, with four phloem and two xylem 
bundles, is found in the roots of Pereskia Pititache, Phyllocactus Hookeri , 
Cereus tortuosus , C. peruvianas, C. Jamacaru, C. Spachianus , C. triangularis , 
Pilocereus exerens, P. albispinus, Ecliinopsis Eyriesii, E. multiplex , E. 
tubiflora and Echinocactus Wislezeni. 
