174 BOTANY. 



branch. The upper leaves have frequently two smaller veins 

 starting from the base of the leaf, and nearly parallel with 

 the midrib (C i). The surface of the leaves is somewhat 

 roughened with hairs, some of which, if slightly magnified, 

 look like little white stars. 



Magnifying slightly a thin cross-section of the stem, it 

 shows a central, ground tissue (pith), whose cells are large 

 enough to be seen even when very slightly enlarged. Sur- 

 rounding this is a ring of fibro-vascular bundles (L, /&.), 

 appearing white and opaque, and connected by a more trans- 

 parent tissue. Outside of the ring of fibro-vascular bundles 

 is the green ground tissue and epidermis. Comparing this 

 with the section of the seedling pine stem, a resemblance is 

 at once evident, and this arrangement was also noticed in the 

 stem of the horse-tail. 



Branches are given off from the main stem, arising at the 

 point where the leaves join the stem (axils of the leaves), 

 and these may in turn branch. All the branches terminate 

 finally in an elongated inflorescence, and the separate flowers are 

 attached to the main axis of the inflorescence by short stalks. 

 This form of inflorescence is known technically as a "raceme." 

 Each flower is really a short branch from which the floral 

 leaves arise in precisely the same way as the foliage leaves do 

 from the ordinary branches. There are five sets of floral 

 leaves: I. four outer perigone leaves (sepals) (F), small, 

 green, pointed leaves traversed by three simple veins, and 

 together forming the calyx; II. four larger, white, inner 

 perigone leaves (petals) (6r), broad and slightly notched at 

 the end, and tapering to the point of attachment. The petals 

 collectively are known as the "corolla." The veins of the 

 petals fork once ; III. and IV. two sets of stamens (E), the 

 outer containing two short, and the inner, four longer ones 

 arranged in pairs. Each stamen has a slender filament (H } /) 

 and a two-lobed anther (an.). The innermost set consists of 

 two carpels united into a compound pistil. The ovary is 



