SCIENCE-GOSSIP. 



J 47 



narrow cells, which are the vascular bundles. One 

 set of them runs up the centre of the radicle, start- 

 ing from its tip ; they pass into the cotyledons, 

 there branch and run to the remoter parts. 

 The cells of the fundamental tissues of the coty- 

 ledons are packed with starch grains of oval shape 

 and pearly lustre, lying embedded in proteids and 

 tannin, with some little fatty substance. The 

 starch grains are stores of food containing carbon, 

 hydrogen and oxygen ; the proteids contain nitro- 

 gen and certain mineral salts. The vascular 

 bundles are the pipes along which this stored-up 

 food will travel to the radicle and plumule, as soon 

 as germination begins. The 

 young epidermis has no part in 

 the storing or conducting of food- 

 material ; it is simply a covering, 

 and will extend with the growth 

 of the young plant inside it. 

 When the swelling seed splits its 

 hard investments, the little radicle 

 lengthens and comes out first, 

 turning downwards and entering 

 the soil slowly ; it wants to get 

 firm hold of the ground and to 

 absorb water. The cotyledons 

 remain in the acorn, and the 

 developing root draws its growing 

 material from their richly-stored 

 cells. They nourish the young 

 plant for months, and may even 

 not be entirely exhausted at the 

 end of two years. The cotyledons 

 play a threefold part ; they are 

 storehouses of food, they are pro- 

 tective to the rudimentary tree 

 pressed closely between them, 

 they also perform the task of 

 thrusting out of the seed-case the 

 tiny plant-germ, that its members 

 may elongate in the two directions. 

 The last two duties are much 

 more quickly performed than the 

 first. In my young oaklings 

 of six to eight inches high, grown 

 in water, the cotyledons were still 

 in the seed-case. I have a young oak pressed in 

 its second year of growth with the cotyledons 

 erect and separate. I suppose the enclosing case 

 simply rotted away during the winter, and so set 

 them free. They are a good deal shrunk, but still 

 much thicker than a foliage leaf. Eventually they 

 get entirely emptied out, die off and disintegrate, 

 so that the place of their connection with the stem 

 can scarcely be discovered. The germination of 

 the beech, which I have often watched, is very 

 different. The cotyledons, though thick and 

 fleshy, are folded up tightly like a fan ; they are 

 drawn out of their nut-like covering very early, 



Fig. 3. — Germinating acorn, 

 showing the manner of 

 emergence of the primary 

 shoot and the first scalps. 



(Ajtcr Rossimisslcr.) 



and then expand and rise till they are thick but 

 ilat and green leaves, as oak cotyledons never 

 seem to be. 



When the radicle of the oak is some two to three 

 inches long, the plumule comes out from between 

 the stalks of the cotyledons, which elongate and 

 separate to permit its passage, and begins its 

 growth up into air and light ; this plumule, too, 

 lives on the stored-up food-stuffs of the cotyledons, 

 the dissolved substances are conveyed into it by 

 the small pipes or vascular bundles arranged for 

 that purpose. As the radicle starts into growth 

 before the plumule, so it keeps ahead of it, being 

 always longer and stouter than 

 the young shoot in air, and beset 

 with side strands or rootlets. At 

 first the young oakling is without 

 leaves, bearing only a few scales ; 

 when it is about three inches high, 

 there are two scales close to the 

 top that are a little longer than 

 those that are below, and from 

 between the scales comes the first 

 leaf, a small green leaf of no very 

 decided shape. Then the stem 

 elongates and throws out other 

 leaves that are distinctly oak- 

 leaves in contour. At the end of 

 summer there are five or six leaves, 

 shortly stalked, each between its 

 pair of stipules. A line drawn 

 round this young stem joining the 

 points of leaf insertion, describes 

 a spiral, which circles twice round 

 the stem and arrives at the sixth 

 leaf immediately over the first 

 one. 



The root of one of my little oaks 

 was infested with a curious and, 

 I suppose, a fungoid growth. In 

 appearance it was something like 

 the barnacles of the sea, bluntly 

 conical protuberances along the 

 crack-like markings on the stoutest 

 part of the root; filmy slime 

 seemed to come off from the pro- 

 tuberances, and thicken the water. A young oak 

 of the same size that I dug out from its native soil 

 bore the same parasite, but in much less degree. I 

 was much interested, but unable to investigate 

 these further. Perhaps some of your readers 

 may be able to tell us something about this 

 parasite. 



As I have already indicated, the observation 

 of the growth of plants from their seeds will be 

 found not only most interesting but, in the case of 

 the larger seeds, such as walnut, oak, beech and 

 others, comparatively easy to manage. 

 Ambleside: July, 1895. 



