DICOTYLEDONES : POLYPETALiE : CALYCIFLOILE. 623 



glomerules in which the terminal flower is usually ? and the 

 lateral ones (^ ; the latter flowers have a simple 4-leaved perianth 

 and four superposed stamens (rarely numerous) ; the former 

 have a trilocular ovary with two ovules in each loculus, the 

 raicropyle of the suspended ovule being directed inwards: fruit 

 a capsule, with loculicidal dehiscence. For the most part shrubs. 



Biixns siempervh-ens, the Box, is an evergreen shrub of Southern Europe ; the 

 wood is valuable. 



Order 3. Empetrace^. Disc wanting : flowers dioecious, with 

 three sepals, three petals, three stamens or a 6-9-locular ovary : 

 ovules solitary, ascending : fruit drupaceous. They are shrubs 

 resembling Heaths in appearance. 



Empetrum nigrum, the Crakeberry, is a small shrub occurring in the north of 

 Europe and in the Alps. 



Order 4. Callitrichaceje. Aquatic plants, with decussate, 

 linear or ovate leaves, in the axils of which stand the solitary 

 diclinous flowers which are destitute of a perianth: the (^ flowers 

 consist of a single stamen; the ? of a bilocular, spuriously 

 quadrilocular, ovary, with four suspended ovules, the micropyles 

 of which are directed outwards. 



Callitriche verna and otber species, forming the section Eu-callitriche, are 

 either partially submerged or they creep on muildy banks, and in them pollin- 

 ation takes place in the air : but in the section Pseudo-callitriche (of which C. 

 autumnalU is the British representative) the plants are entirely submerged, and 

 consequently pollination takes place under water (see p. 434). 



This order has been associated with the Haloragidac m ; but the general 

 structure of the flower, especially the remarkable reduction wbich it presents, 

 and the number and attachment of the ovules, seem rather to indicate affinity 

 with the Euphorbiaceae. 



SERIES III. CALYCIFJiOR^. 



Flowers epigynous or perigynous : calyx usually gamosepalous : 

 stamens definite or indefinite : gynajceum syncarpous or apo- 

 carpous. 



Cohort I. Umbellales. Flowers regular, sometimes actino- 

 morphic, epigynous, with generally a single whorl of stamens 

 opposite to the sepals : calyx inconspicuous : ovary bilocular, with 

 one ovule in each loculus : a disc between the stamens and the 

 styles: inflorescence usually umbellate: seed containing endo- 

 sperm : leaves exstipulate. 



V. S. B. S S 



