ON THE STRUCTURE AND CLASSIFICATION OF SEEDS. 183 



pearance in the solar microscope. It is all composed of 

 extremely dirainvitive netted bags, of thick juice, without 

 any vessels — in short, it Is the first formation of the pabu- 

 lum or softer part of the wood ; and when ready prepared 

 for the sap vessels, they shoot their way through this soft 

 substance. In a graft, which I have repeatedly tied up 

 again, before the vessels had begun to appear, and when I 

 reopened it, I found them and the wood perfectly complete. 

 I have taken this matter from a graft, from a fresh budded Howobtaina* 

 plant; from the interior of a seedy and sometimes from the °'®* 

 shooting of the fresh line of the wood, but this is generally 

 too hasty a performance to profit by ; the fresh wound of a 

 tree is the best way of getting it (next to a graft) if well 

 preserved from the air, and in a fortnight plenty will be 

 found. But the specinjen must be quickly taken, or the 

 wood vessels will shoot. This is the true cambium, the 

 softer part of the wood, before the sap vessels shoot. But 

 I must notice, that the bark is not made in the same man- 

 ner: it is formed all at once, soft and hard; the vessels 

 shoot, while the rest is forming. Mr. Knight very properly 

 observes, ^hat in a graft the fresh wood always resembles 

 exactly th^ wood of the graft, and not the stoqk. 

 I am. Sir, 



Your obliged servant, 



AGNES IBBETSON. 



The five classes into which I have divided the seeds. Classes 



seeds. 

 Common seedy or first class. 



,, .£. * ii r Oak, elm, beech, horse-chest- 



Mamm.ferous, or teat-bear, i ^ ^^ ^ ^^^^ 



ing. See walnut, PI- V,),^^^^ burdock, sunflower, 

 figs 1 2,3; apncot, H^.\^^^^ ^^ ^ther compound 

 ^' ^' ^' Cflowers, 



Second cl^ss^ 



Leaf-bearing or foliferous. (^ 



See figs. 8 and 9, showing! Firs and spontaneous planta 

 the whole embryo, when I of the soil, as arenarias, stel- 

 forced out of the seed in/ larias, potentillas, euphor- 

 the manner described a- i bias, and many of the running 

 bove ; and fig. 7, the heart, I plants^ &c. 

 or corculum* alone, I 



• ^ Third 



