102 



BOTANY. 



however, by making a large number of very thin sections of the whole 

 leaf (by placing it between two pieces of elder pith), when it will be 

 found that in some cases stomata have been cut through in the man- 

 ner shown in Fig. 92. 



(6) Examples may be obtained from any of tlie higher plants, but 

 those which are of a firm texture and have a smooth epidermis are 

 best to begin with — e.g., the hyacinth, tulip, the lilies, many grasses, 

 f aclisia, lilac, etc. 



(o) Weiss* determined the number of stomata on the epidermis of 

 both surfaces of 167 leaves of plants ; some of his results are given 

 below : 



In one square millimetre. 



Upper side. Under side. 



Olea Europea 



Vinca minor 



Juglans nigra 



Ailanthus gland ulosa 



Syringa vulgaris 



Helianthus annuus 



Brassica oleracea 



Platanus occidentalis 



Populus dilatata 



Solanum dulcamara 



Euphorbia cyparissias 



Madura aurantiaca 



Betula alba 



Berberis vulgaris 



Pisum sativum 



Buxus sempervirens 



Prunus Mahaleb 



Asclepias incarnata 



Datura stramonium 



Taxus baccata 



Zea mais 



Chenopodium ambrosioides. 



Ficus elastica 



Ribea aureum 



Populus monilifera , . 



Pinus sylvestris 



Anemone nemorosa 



Jjilium bulbiferuni 



Iris Germanica 



Avena sativa 























175 



138 







55 



60 



















101 











67 



114 







94 



184 











89 



50 











63 



48 



625 

 477 

 461 

 386 

 330 

 325 

 302 

 278 

 270 

 263 

 259 

 251 

 237 

 229 

 216 

 208 

 204 

 191 

 189 

 166 

 158 

 156 

 145 

 145 

 131 

 71 

 67 

 63 

 58 

 27 



In one square inch. 



Upper side. Under side. 























113,875 



88,910 







85,475 



38,700 



















65.145 











43,215 



73,530 







60,630 



118,680 











57,405 



33,350 











41,925 



30,960 



408,125 



308,665 



298,345 



348,970 



312,850 



309,635 



194,790 



179,810 



174,150 



169,635 



167,055 



161,895 



153,865 



147.705 



139,830 



134,160 



131,580 



133,195 



131,905 



107,070 



101,910 



100,630 



93,535 



93,535 



84,495 



45,895 



43,315 



39,990 



38,410 



17,415 



*Iu a paper on the Number and Size of Stomata, published in 

 Pringsheim's " Jahrbiicher filr Wissenschaftliche Botanik," 1865. 



