GLOSSARY 161 



Raceme. A simple flower-cluster (wild cherry). 



Rachis. The axi& of a pinnate leaf etc.; sometimes continued 

 as a spine or bristle (pea tree). 



Radiate. The same as digitate when applied to leaves or their 

 veins: with conspicuous flowers around the outside (head 

 of sunflower; inflorescence of Hydrangea or Viburnum). 



Raised. Lying wholly or in part above the general surface of 

 the twig, as applied to leaf-scars. 



Ranks. As applied to leaves, the longitudinal lines on the stem 

 in which foliage is arranged: usually 2, 3, 5 or 8 for alter 

 nate leaves; and 4 for opposite or obliquely opposite leaves. 



Receptacle. The part of a stem that bears the parts of a 

 flower, or that bears the flowers in a conden&ed inflores- 

 cence like that of sunflower or fig. 



Reflexed. Bent downward or backward. 



Resin-passages. Intercellular spaces in the wood of conifers: 

 appearing as pores in cross section, and so capable of being 

 mistaken for ducts' which are absent from such wood. 



Resinous. With copious resin (wood of pine, buds of fir, etc). 



Reticulate. Netted, like the finer veins of an oak leaf or the 

 ridges on the stone of a hackberry fruit. 



Retrorse. Turned backward or downward. 



Revolute. With the margin rolled back, as applied to leaves. 



Rhombic. Four-sided with the opposed sides parallel, but not 

 rectangular: diamond-shaped. 



Ribbed. With longitudinal ridges more prominent than is in- 

 dicated by striate, and more distinct and clearly isolated 

 than fluted indicates. 



Ring-porous. Wood in which each year's layer is marked by 

 large or crowded ducts in the spring growth: contrasted 

 with diffused-porous. 



Rugose. Wrinkled or with the veins impressed. 



Salver-shaped. With a slender tube and spreading border, like 

 the corolla of phlox. 



Samara. A winged fruit (ash, maple, elm, ailanthus). 



Sap. As here used, the fluid that flows from a freshly cut 

 twig or leaf-stalk. 



