110 TISSUE SYSTBlf. 



DIGESTIVE HAIBS of many insectivorous plants, GLANDULAR HAIRS on 

 the scale of the winter bud of Aesculus Ifippocastanum, and vari- 

 ous kinds of BARBED HAIRS from Mentzelia ornata. 



Strasburger, pp. 72-82; DeBary, pp. 59, 89, 94, 95; Bastin, 

 pp. 42-47. 



It will be noticed that true plant hairs (trichomes) are but a 

 part of the epidermis which has become differentiated, while thorn's 

 are modified branches, and are connected with the vascular system 

 of the plant, e. g., thorns of locust. 



For the study f>f Water Pores, in part modifications of the 

 epidermis, the leaves of Tropaeohnn, Aconitum or Ficus elastica, 

 furnish excellent material, but are not always readily accessible. It 

 will be sufficient in this connection to refer to the study made of 

 the leaf tooth of Fuchsia, p. 97. 



Additional studies could profitably be made of many of the 

 modifications which the epidermis undergoes, but it is believed that 

 enough has already been given, to familiarize the student with the 

 more important characters of this interesting tissue system. 



2. Fibre Vascular System. 



3. Fundamental System. 



Illustration: These Systems should be considered in the fol- 

 lowing groups of plants: (1) EXOGENOUS STEMS, herbaceous (Be- 

 gonia), and woody (Moon Seed Vine). (2). ENDOGENOUS STEMS, 

 herbaceous (Corn), and woody (Smilax hispida). (3). CONIFERAE. 

 (4). VASCULAR CRYPTOGAMS. (Figs. 16, 17, 27, and 28). 



Since studies have previously been made of the elements of the 

 Fibre -vascular bundle, in each of the groups as outlined, it is only 

 necessary in the brief course here included to examine the distribu- 

 tion of the tissues in each of the cases mentioned, together with 

 the relations of the three tissue systems. To this end, careful 

 series should be made of the tongiseetion and transection of stems 

 from the plants indicated. De Bary, p. 232; Goodale, pp. 126- 

 135; Vines' Text Book of Bot., p. 170. 



It must be remembered that the VASCULAR SYSTEM of ROOTS, 

 LEAVES. AND THEIR MODIFICATIONS should be included in the considera- 

 tion of this subject. 



By examination of the material indicated make outline sketches 



