TREES WITH HIGHLY-DEVELOPED FLOWERS 311 



merely of two stamens joined at the base (4). The 

 female flowers have a much-reduced calyx and a superior 

 pistil of two united carpels, and there are two large stigmas. 

 The hermaphrodite flowers have no perianth, but two 

 stamens below the pistil (5). 



The flowers are wind-pollinated, and only one seed 

 matures. As the fruit ripens, the free end of the ovary 

 enlarges into a flat, leathery wing, and forms a samara 

 carried by the wind. A young fruiting branch is shown in 

 6, and the floral diagram in 7. The structure of the fruit 

 has already been studied (p. 24, Fig. 9, 1 and 2). 



Lilac 



The Lilac (Syringa vulgaris) (Fig. 205) is a native of the 

 wooded slopes of Persia and Central Europe, and was 

 introduced into Britain at the beginning of the seventeenth 

 century, when many of our common ornamental trees were 

 brought to this country. It is a shrub ten to fifteen feet 

 high, and is often surrounded by numerous suckers from the 

 roots. The suckers grow rapidly, forming long, straight, 

 switch-like shoots. This increase in vegetative growth 

 tends to reduce its flowering activity, hence the removal 

 of the suckers in cultivation. 



The bark is greenish-brown, fissured and scaly ; and the 

 small, slender branches are grey to olive, with conspicuous 

 oval lenticels. 



The end bud of the ordinary branches often dies, and 

 since the lateral buds are in crossed pairs, this leads to 

 the forked branching (false dichotomy) which is such a 

 striking feature of the shrub. The large inflorescence-bud 

 is also terminal, and forked branching occurs here after 

 flowering, as in the Sycamore and Horse-Chestnut. 



