264 MONOCIILAMYDE^ 



prising a large proportion of our English forest trees. They have 

 been subdivided by botanists into several Sub-orders, or groups, 

 four of which contain British specimens. The first Sub-order, 

 Salicine^e (the Willow group), is distinguished by bearing all its 

 flowers in catkins, the fruit being a 2-valved capsule, containing 

 numerous seeds tufted with down. In the Sub-order, Myricejj 

 (Sweet-Gale group), the flowers are all in catkins, and the ripe fruit 

 assumes a drupe-like apipearance, from Ijeing invested by the 

 fleshy scales of the catkin. In Betuline^ (Birch group) the 

 flowers are all in catkins, and the fruit is thin and flattened, con- 

 taining I or 2 seeds, which are not tufted with down. In CuPULi- 

 FBRJE the fertile flowers grow in spikes or tufts, the barren flowers 

 in catkins, and the fruit is either wholly or partially invested with 

 a tough case, termed a cupula. By some modern botanists these 

 groups are severally treated as distinct Orders, under the names of 

 Salicace.e, MvRicACE.iE, Betulace.e, and Cupulifeile ; but it 

 has been thought expedient to retain the few examples described 

 in this volume under the comprehensive Order Amentace^. 



Suh-order I, Salicine^. — Willow Group 



1. Salix (Willow). — Stamens and pistils on different plants 

 (dioecious) ; scales of the catkin imbricated, entire ; stamens 1-5 ; 

 stigmas 2 ; capsule of 2 valves, i-celled ; seeds numerous, tufted 

 with cottony down. (Name, the Latin name of the plant.) 



A very large genus, widely distributed from the tropics to the 

 Arctic regions, and found both in low-lying lands and at great alti- 

 tudes. This is perhaps the most puzzling famfly with which the 

 student will meet. Not only do many confusing natural hybrid 

 forms occur, but botanists often find it difficult to " pair " the male 

 and female forms of the same species. As many as thirty British 

 species have been described, but the truly distinct forms are pro- 

 bably about half that number. For a detailed description of the 

 species the student is referred to Bentham and Hooker's " British 

 Flora," or John's " Forest Trees of Britain." 



2. PoPULUS (Poplar). — Stamens and pistils on different plants ; 

 scales of the catkin jagged ; stamens 8-30 ; stigmas .4 or 8 ; capsule 

 of 2 valves, obscurely 2 - celled ; seeds numerous, tufted with 

 cottony down. (Name from the Latin, populus, and signifying 

 ths tree of the people, which it was considered to be at Rome and in 

 France during the revolutions.) 



The three principal British species are — 



P. alba (White Poplar, Abele), — A tall growing tree, with smooth 

 ash-grey bark ; ovate-cordate, lobed leaves, white, with cottony 

 down on the under side ; buds downy ; the roots send up many 

 suckers. Perhaps indigenous and much planted. 



