RAN ALES 



391 



from the stele, the two lateral traces from the cortical system, where 

 each is united in origin with a lateral trace of an adjacent carpel. The 

 flowers of Calijcanthus, the Himantandraceae, and the Annonaceae 

 have a somewhat similar but less strongly developed, cortical system. 



The nodes of the vegetative axis have 6 to 17 traces. In other Ranales, 

 only Eupomatia approaches this high number of leaf traces. 



The wood of the Magnoliaceae is more advanced than that of most 

 other ranalian families. It has vessels of a fairly high type — scalariform, 

 with a few widely spaced bars, and, in some genera, simply perforate — 

 and terminal parenchyma. 



Fig. 141. Diagrams of longitudinal sections of carpels and ovules of the Magno- 

 liaceae showing complex vascular supply derived from both stelar and cortical 

 bundles of receptacle. A, Magnolia acuminata; B, Liriodendron tulipfera. 



A prominent feature of flower structure in this family is the absence 

 of staminodes, in strong contrast with the Himantandraceae and 

 Eupomatiaceae, where they form prominent parts of the flower. 



The Magnoliaceae provide an excellent example of lack of uniformity 

 in advance from primitive characters among closely related taxa. 

 Magnolia is commonly considered the most primitive genus and Lirio- 

 dendron, one of the most advanced. But species of Michelia are more 

 primitive in their deeply sunken microsporangia and in the prominence 

 of the protrusion of the connective. If the solitary flower represents a 

 reduced inflorescence, Michelia is more primitive in its clustered flowers. 

 Liriodendron has an advanced type of stamen, with long filament and 

 absence of protruding connective. Michelia has carpels of primitive 

 form, with weak differentiation of style and stigma. Kmeria shows high 

 specialization for ranalian families in its unisexuality, and Pachylarnaxy 

 in its syncarpy. 



