THE OBOUPS OF TISSUES, OR TISSUE-SYSTEMS. 57 



are required, while lower down all older stages may be obtained. In 

 these note the cambium-zone. 



(g) Make very thin cross-sections of a root of germinating Indian 

 corn. The first section should be made within a few millimeters of 

 the root-tip. Others should then be made at a greater distance. By 

 staining the specimens with carmine the sieve-regions may be demon- 

 strated better. Note the bundle-sheath. 



(h) Study in like manner the bundle in the stem of the Club-mosses 

 (some of the species are known as Ground-pines), and if possible 

 make comparison with sections of the smaller Club-mosses (grown in 

 greenhouses often under the name of Lycopodium, although they are 

 in reality species of Selaginella). 



(i) Dig up the underground stem of the common Brake-fern 

 (Pteris) ; preserve what is not wanted immediately in alcohol. The 

 bundles may be seen by the naked eye by making a clean cross-cut 

 and examining carefully in the region immediately surrounding the 

 two dark masses of fibrous tissue. Make thin cross-sections and 

 study with the microscope, comparing with Fig. 36. Longitudinal 

 sections in two planes should be made as in c and d above. 



{j} Make very thin longitudinal sections of some of the reduced 

 bundles which constitute veins and veinlets of leaves, e.g., in gera- 

 nium and primrose. 



(k) Make similar sections of the bundles of petals, e.g., fuchsia. 



(I) Soak petals of fuchsia for several- days in potassic hydrate, 

 then wash in water and carefully mount in pure water. The reduced 

 bundles may generally be well seen by this treatment. 



96. The Fundamental System of Tissues. — This system 

 includes all the tissues v^hich in any part of a plant fre- 

 quently make up the bulk of that part, but are not in- 

 cluded in the epidermal or fibro-yascular systems. Thus 

 if from any stem, for example, we should strip off the epi- 

 dermis and then pull out the fibro- vascular bundles, that 

 which remained would be the Fundamental System of 

 Tissues. In those plants (of the lower classes) which have 

 no fibro- vascular bundles everything inside of the epidermis 

 belongs to the fundamental system. On the other hand, 

 in the stems of our woody trees there is but very little of 

 the fundamental system present, making up the very small 



