WHAT PLANTS NEED 3 



firmly around the seeds to bring them in close touch 

 with it. Thev__can take up water 

 cover touches the soil, for the 

 to absorb water. The covers of some seeds have this 

 power to a great degree. The covers of other seeds 

 (like buckeye or castor bean) seem at first sight to be 

 almost waterproof, but they are able to take up water 

 slowly. We sometimes crack or break hard seed covers 

 (nuts, peach pits), or put them in a pan and rub them 

 with sand, which serves the same purpose (small flower- 

 seeds) . This lets the water in, and they sprout quickly. 

 Acacia seeds are boiled two or three minutes to soften 

 the covers and make them take up water. 



FIG. 1. The bean at the left has soaked in water only a few minutes. 

 The next one has soaked a little longer. The one at the right has soaked 

 longest. The wrinkling shows where the water begins to go in and how 

 it spreads inside. 



Spme_geeds take up water easily because their 



ings seize upon^it and fill themselves with it. These 

 coverings may be spongy (nasturtium) or like mucilage 

 (flax, quince, radish) or fibrous (outer husk of walnut). 

 The chaff of grain and the pulpy covering of fruits and 

 berries also act in this way. Put these and other seeds 

 in water to see how they act. 



Most seeds have openings by which the water enters 

 and spreads in the seed (figures 1 and 2). If we place 



