A BIT OF GROUNDSEL. 103 



caused by the enlarged growth of the cells on the end of the 

 flower-stalk. A like process, but on a much more extensive scale, 

 produces the edible heads of the garden artichoke {Cynara 

 scolymus)^ and the luscious strawberry. The stamens which pro- 

 duce the pollen-dust are found in all the Compositce within the 

 tube of the corolla ; and their anthers are united into a tube 

 which encircles the style, whence the plants belonging to this 

 natural order are called in the Linnsean system Syngejiecious (Plate 

 XI., Fig. lo). 



The style (Plate XL, Fig. 9) is well worth attention. It is 

 slender and thread-like, and spHt at the top ; the two portions 

 curving away from each other. The tips and upper surfaces of 

 these are densely set with little processes, from which is exuded 

 the sticky substance that retains the pollen when it falls upon it. 

 It is evident that the position of these processes on the tipper with 

 none on the under sides of the stigma, is to ensure cross, and to 

 prevent self fertilisation. 



Let us next take the stem, which is channelled or streaked 

 with longitudinal lines, and, as seen in the transverse section 

 (Plate XIL, Fig. 2), sHghtly angular; botanical books describe it as 

 -' glabrous, or bearing a little loose cottony wool." This " wool " 

 is found chiefly on the young parts — in the forks of the branches 

 and leaves, and is of the nature of trichome or plant-hairs ; here 

 it is a string of cells, like glassy beads (Plate XIL, Fig. 8), and is 

 similar to the larger hairs of the common Sow Thistle, SoncJms 

 pahistris. 



If we now make a transverse and also a longitudinal section, 

 and note the arrangement and shape of the cells in each, we shall 

 see that all are nearly cubical, except those of the cuticle, which 

 are six times longer than they are wide. Here are to be observed 

 the three systems of tissues, viz. — (i) the epidermal, (2) the ground, 

 and (3) the fibro-vascular. i. — The epidermal tissue, there being 

 no bark (Plate XIL, Fig. 3 and Fig. i a), is one row of long 

 and flattened cells. 2. — The ground or fundamental tissue (Plate 

 XIL, Fig. 4 and Fig. i ^), some of the cell-layers of which are 

 filled with purple colouring-matter immediately outside the fibro- 

 vascular bundles. The cells of the ground tissue gradually 

 increase in size towards the centre of the stem, till they are rup- 



