The Presidents Address. By Lord Avebury. 



277 



globular 



and the poppy-heads are swung backwards and forwards, the seeds 

 are jerked out of the capsules. As usual in such cases they are 

 small, and deep brown or nearly black, and thus less conspicuous 

 to birds. They are also more or less pitted. In form they are 

 more or less reniform. 



As regards our four indigenous Poppies, they may be distin- 

 guished as regards the capsules as follows : — 



Capsule, club-shaped \ £ ff^one, hairy. 

 r (P. dubium, smooth. 



( P. hybridum, hairy. 



( P. Rhmas, smooth. 



In P. Argemone the plant is altogether hairy, perhaps as the 

 result of its living in dry regions, and the 

 hairiness of the capsule probably has reference 

 not so much to the capsule itself as to the 

 general habit of the plant. 



In Glaucium (the Horned Poppy) and Che- 

 lidonium the fruit is a pod, and dehisces like 

 that of the Leguminosa?, but while in Glau- 

 cium it opens from the apex downwards, those 

 of Chelidonium do so from the base upwards. 



In Chelidonium the base of the capsule 

 matures, and naturally opens, first. In Glau- 

 cium, however, the pod is much longer, reach- 

 ing from 10 inches to a foot. If the valves 

 separated at the base, the placentas would have 

 to support the whole weight, and would pro- 

 bably give way, in which case the pod would 

 collapse, and the seeds would not be properly 

 scattered. 



The seeds of our Poppies, and of Glaucium, 

 as of so many species where they are jerked 

 out of capsules, are deeply pitted ; those of 

 Meconopsis, Roemeria, and Corydalis are reticu- 

 late ; those of Chelidonium smooth and black. 



CrucifeR/E. — This great family is generally 

 divided for purposes of convenience by the 

 relative length of the pod, and the arrangement of the radicle 

 with reference to the cotyledons, which in some cases have their 

 edges to the radicle (accumbent), while others have the radicle 

 folded over one face (incumbent). The fruit is generally a pod, 

 divided into two cells by a thin partition. It is generally con- 

 sidered that the pod originally consisted of four carpels, but this 

 is now the case in one genus only, Tetrapoma. The valves of 

 the pod generally separate at maturity, but in a few genera the 

 pod is indehiscent. The surface of the seed is generally smooth ; 

 but there are a few interesting exceptions. Some are very much 



Fig. 67.— Capsule of 

 a Poppy, a, indi- 

 cates level of aper- 

 ture. 



