74 IMIF.KITANCE <>F KEP COLOUR IN Jl'TK. 



to serve as a vegetable. Tlio races may l>e grouped conveniently 

 under the following colour types : — 



{'() deep red stem, petioles and fruit?:, with the teeth of the 

 leaves also tipped with red ; 



(h) brownish red stems, petioles and fruits, witli no tlistinct 

 red borders to the leaves ; 



(c) green stems with reddish petioles and fruits : 



{(l) pure green stems, ])etioles and fruits. 



The tints of the various red races contained in group (a) or 

 group (/>) were not, of course, exactly identical : the members of 

 the groups («), (li), and (c) rather formed a series of colour 

 gradations between the extreme types — pure red and pure green. 



The red colour is a soluble pigment, turning brilliant mala- 

 chite o-reen with alkali and 1 right carmine with acid, '•' found — 



(t) chiefly in the brick-shaped parenchyma cells, which lie 

 immediately under the epidermis of the stems and petioles ; 



(/(') in the parenchyma of the petioles, sporadically, even as 

 deep as the phloem ; 



(Hi) ir. sub-epidermal cells near the margin of the leaf and 



{ic) in small multicellular hairs on the leaf and on the stipule.s. 



The intensity of the colour of a red-stemmed jute is due 

 to an almost general distribution of the pigment in the .sub-epi- 

 dermal cells of the parts coloured. Cjiiversely, the fewer the 

 pigmented cells the less red the stem ; until, in pure green races, 

 they are absent. Even the stems of members of class (c) (green 

 stems with red petioles) shew, under the microscope, a few red 

 cells. There are therefore only two real colour types in jute, 

 capable of exact, ready definition, viz. : — red and green ; and the 

 clas.ses (ft), {!>) and (c) in the colour scheme given above, are 

 convenient but arbitrary divisions of degree in colour, without 

 definite boundary lines. 



When a jute seedling appears above ground, whether it be 

 of a red or of a green stemmed race, it is, to the eye, wholly' 



• A pure green plant — onn wlilch. under tlie microscope, elmws no red cells at all-^iloei' 

 not (siTC this rolour reaction. 



