VEINS. 



87 



a. In our description of individual forms, we shall select only the most remark- 

 able, leaving others for explanation in the Glossary. 



The most obvious arrangement is that wliich is founded upon the modes of the 

 veining ; but it should be premised that diiferent forms of venation often give rise 

 to the same outline. 



232. Of FEATHER-VEINED Icaves, the following forms depend 

 on the length of the veinlets in relation to each other, and to the 

 mill vein. If the middle veinlets ai-e longer than the rest, the leaf 

 will be 



1, Orbicular (roundish), as in Pyrola rotundifolia. 



FIG. 29. — Figures of feather-veined leaves. The numbers refer to paragraplis. a, deltate 

 leaf of Populus. 



2. Elliptical (oval), as in Lespedeza prostrata; or 



3. Oblong (narrow-oval). Ex. Arenaria lateriflora. 



If the lower veinlets are longer than the rest,the leaf will be 



4. Ovate (egg-shaped), as in the Mitchella repens, or 



5. Lanceolate (lance-shaped), narrow, and tapering to each 

 end. Ex. sweet-william. 



When the veins are most developed towards the summit of 

 the leaf, it becomes 



6. Obovate (inversely egg-shaped), as in the walnut; or 



7. Spathulatc (shaped like a spathula), as in the daisy. 

 Again, if the lowest veinlets are longest, sending off veinulets 



backwards, the leaf will be 



8. Cordate (heart-shaped), hke the ovate fcirm, with a hollow 

 (sinus) at the base, as in the lilac. 



9. Aiiriculate, having ear-shaped lobes at the base. Ex. 

 sage. 



8* 



