GLANDULA& HAIRS WAX. 99 



cross-section through a winter bud of the horse-chestnut (^Esculus 



Hippocastanum) shows us button-shaped glandular hairs, situated 



on the protective scales of the bud (Fig. 38). The intermediate 



scales of the bud bear glands on 



both sides ; on the external ones 



more are found on the inner side, 



on the inner scales the most on the 



outer surface. The structure of 



the glands in longitudinal section 



is shown in the figure ; there is an 



axial cell-row, which towards the 



top divides, and from which the 



secreting cells radiate. The cuticle t .^? G - 38. -Glandular hair ^ on a scale 



of the winter bud of ^Esculus Hippo- 

 is ruptured by the secretion, and castanum covered with secretion ( x 



this is discharged between the 



scales, coating them and sticking them together. This secre- 

 tion consists of a mixture of gum and resin, In water the 

 gum-drops scattered in the resin can be seen to swell ^ while, 

 on the other hand, by the addition of rosaniline violet the resin 

 mass is coloured a beautiful blue, and the contents of the 

 glands are red. The winter buds of the horse-chestnut can also 

 be preserved as alcohol material. Section-cutting from this 

 material is easier, and the glands can be more readily studied ; 

 but, naturally, the resin will have been removed by the alcohol. 



Wax, On one object (Iris florentina) we have already drawn 

 attention to the finely granular layer of wax which covers the 

 outer surface of the epidermis ; we propose, however, to specially 

 study it upon some other plants. 



Very suitable for this is Echeveria secunda-glauca, or other 

 similar plant, so often used in gardens for "carpet-bedding". 

 The wax-layer, which can easily be wiped off, gives to the plant 

 a hoary or "glaucous" appearance. A surface view of the 

 epidermis shows us a net-like crust of aggregated grains. 



Aggregated short rods forming a wax -layer can be seen in 

 an easily observed form in the surface view of the epidermis of 

 Eucalyptus ylobulus, the Australian blue-gum tree. 



Similar delicate rodlets are shown upon cross-sections of the 

 surface of adult internodes of the Bye, Secale cereale. 



The most beautiful object, however, is the sugar-cane (Sac- 

 charum officinarum'), so commonly cultivated in the plant-houses 

 of botanical gardens, etc. Here the wax covering appears in the 



