64 PEDICULARTS CANADENSIS. COMMON WOOD-BETONY. 



altered from true leaves, forming a verticil under the spike of 

 flowers. We see by this that the leaves had been j^retty well 

 developed before the drawing in of the spiral coil commenced, 

 and the lesson taught us by our flowxr is therefore this, — tliat 

 the matter of time in the acceleration and retardation of develop- 

 ment is the main cause of many of the varied forms found in 

 vegetation. When the accelerated motion precedes leaf devel- 

 opment, as in many plants it does, there may be but very small 

 bracts, or even no bracts at all. In most other species of PediciL- 

 laris the development is regular, and the involucral-like circle 

 of bracteal leaves does not exist. 



A further lesson we may gather from the flowers. The 

 bracts — the small leaflets amono: the flowers — are changed 

 leaves, and the flowers which spring from the axils are analogous 

 to the branches which spring from the axillary bud at the base 

 of the perfect leaf. A flower is, therefore, a modified brancli, as 

 the bract is a modified leaf. In many flowers we can trace the 

 relations of the floral parts to leaves and branches ; but in 

 this the arrestation has been so severe that we lose all resem- 

 blances in the flower, and we cannot tell whether the corolla is 

 made up of a single leaf or several. The attention of the stu- 

 dent is directed to this point because here will ultimately be 

 found the full explanation of the reason why flowers are some- 

 times of very peculiar forms. 



Generally, we can tell what form the seed-vessel will assume 

 before the petals or the corolla fade ; but in this Pcdicidaj^is, the 

 capsule continues to grow, and ultimately assumes a sword-like 

 beak, projecting beyond the calyx. (See Fig. 2.) When mature, 

 it opens by a slit on tlie upper side through which the ripe 

 seeds escape. Altogether it is a very interesting plant to study, 

 as well as a pretty ol^ject to look at for those who wish to enjoy 

 only the external beauty of nature. 



Explanation ok tiik Plate. — i. A single branch fro:n a root-stock. — 2. Calyx and mature 

 seed-vessel. 



