6 



largest. Each of these primary veins again gives rise to numerous 

 secondary and tertiary veins distributed in such a way as to form a 

 perfect network of fibre. The veins are raised on the under-surface 

 of the leaf, but rather sunk- in if observed on the upper side. 



The two surfaces vary also in many other respects. The under- 

 surface is usually downy, whilst the upper is seldom so. The under 

 side is always of a paler colour than the upper. 



In structure the leaves of the vine consist of an epidermis or outer 

 skin, which covers both sides of the leaf, and encloses the paren- 

 chyma or cellular tissue, the cells of which contain the chlorophyl 

 or green colouring matter. 



On the under side of the leaf are to be found the stomata or breath- 

 ing pores, to the number of 13,600 per square inch. These may be 

 termed the lungs of the plant, as it is through them that the air is 

 brought in contact with the inner tissues, which are thus enabled to 

 absorb necessary gases from the air, and to get rid of those 

 eliminated during the process of nutrition, as well as a large amount 

 of water. On the upper surface there are no stomata. 



On the epidermis are hairs, which are either stiff or long and silky, 

 the former on the under side of most vine leaves, especially on the 

 veins, whilst the latter constitute the cottony down occasionally 

 present on the under or on both sides of the leaf. 



FLOWER. 



The flowers of the vine are grouped in bunches, which are too 

 familiar to require description. The bunch is botanically termed a 

 raceme, and is an example of indefinite inflorescence. The flower 

 itself is small and insignificant looking, and of a pale green colour. 

 It may be described as follows : 



Calyx small, almost entire, formed of five sepals united at their 

 base. Corolla, usually composed of five petals, alternate with the 

 sepals and cohering above; when the bud opens they are set free at 

 the base, but remain united at the summit, so that the whole corolla 

 falls off in a single piece. Stamens, usually five in number, opposite 

 to the petals, the anthers being ovate and versatile. Alternate with 

 the stamens are five nectariferous glands, which give rise to the 

 fragrant perfume of the flower. Pistil style short. It is divided 

 into two cells, each with two ovules. This is the complete or 



