410 MORPHOLOGY OF THE ANGIOSPERMS 



of the genus — leaves, inflorescences, and fruits — show that it was repre- 

 sented in the Upper Cretaceous and the Tertiary by several species. 



The flowers, without perianth, subtended by bracts, are crowded to- 

 gether on short axes, forming inflorescences which have frequently been 

 interpreted as flowers. The fossil inflorescences show that the flowerlike 

 inflorescences of the living species represent reduced racemes. Evidence 

 that the "flowers" are inflorescences is the presence of bracts which sub- 

 tend small clusters of stamens, in the staminate inflorescences (Fig. 

 146A), and individual carpels, in the pistillate (Fig. 146B). Individual 

 flowers are recognizable in the staminate inflorescences, but reduction 

 of the pistillate flower has been to a solitary carpel, and the compact 

 cluster of these carpels closely resembles a flower. But the presence of 

 a bract subtending each carpel (Fig. 146B, 2) demonstrates that the 

 "flower" is an inflorescence. Vascular anatomy supports this interpreta- 

 tion. The interpretation of the pistfllate inflorescence as a flower re- 

 quired an explanation of the apparent abaxial position of the sutLire of 

 the carpels, a position unknown elsewhere in angiosperms. (There is no 

 evidence, either in external form or in the position and orientation of 

 the vascular bundles of the flower, of a possible twisting of the carpels 

 or flower like that characteristic of some orchids.) 



The stamens are primitive in their prolonged connective and basi- 

 fixed anther, and the latrorse position of the sporangia; the carpels are 

 primitive in their stipitate form and prominent, decurrent stigmatic 

 ridges. The pollen is tricolpate, with unusual furrowing. The secondary 

 wood has primitive scalariform vessels, with numerous perforations 

 (Fig. 22). 



Characters that place the Cercidiphyllaceae apart from other ranalian 

 families are the great variety of leaf form, perhaps showing transition 

 from pinnate to palmate venation; the subopposite placing of flowers 

 in the inflorescences ( irregularly opposite and alternate in fossil species ) ; 

 sporophylls with unusual combinations of primitive and advanced 

 characters — the carpel with a long style and a decurrent, two-ridged 

 stigma (Fig. 146B), the stamen with a long slender filament and a 

 prolonged connective (Fig. 146A). Remarkable also is the association 

 of highly primitive xylem with highly advanced inflorescence and re- 

 duced flowers. 



MONIMIACEAE 



The Monimiaceae, a rather large family of woody genera of varied 

 habit, show much variety in morphological characters; they, like other 

 ranalian families, combine primitive and advanced characters — some of 

 the primitive characters of the Magnoliales and some of the advanced 

 characters of the Laurales. The flowers range from bisexual to vmisexual, 



