THE DICOTYLEDONES 



1685 



are few general anatomical features though a tendency to form scalariform 

 perforations in the vessel walls is of frequent occurrence. Hydathodes on 



O 



Fig. 1543. — Floral diagram of 

 Sa.xifraga gramdata (Saxi- 

 fragaceae). [After Eichler.) 



the leaves and chalk glands connected with them occur in some genera, 

 especially Saxifraga, where they distinguish certain sub-genera known as 

 the " Crusted Saxifrages". The family is subdivided as follows: 



Fig. 1544. — Saxi'fraga grauiduta. Longitudinal section of flower. 



I. Saxifragoideae 



Herbs of varying habit, leaves alternate, flowers pentamerous or tetra- 

 merous. Gynoecium bicarpellary, either hypogynous or epigynous, with 

 one or two loculi. Saxifraga (Fig, 1545), Tellima, Chrysosplenium, Par- 

 nassia, Heiichera, Astilbe. 



