260 



MONOCHLAMYDE^ 



3. Buxus (Box) 



I. B. sempervirens (Common Box- tree). —A 

 small, well-known tree, growing in great abun- 

 dance, and apparently wild, on Box-hill in Surrey, 

 where it ripens its seeds. In a natural state it 

 attains a height of 8 or 10 feet ; in gardens it is 

 often clipped into various shapes, and a dwarf 

 variety is commonly used^ as an edging to beds. — 

 Fl. April. Small tree. 



Natural Order I.XXIV 



CALLITRICHACE.E.— Water Star- wort Tribe 



Flowers in different parts of the same plant, 

 axillary, solitary, very minute, imperfect, with 

 two white brads at the base ; calyx and corolla 

 absent ; barren flower, with one stamen, or very 

 rarely two ; filament thread-like, bearing a i-celled 

 anther, which opens at the summit by two trans- 

 verse valves ; fertile flower, ovary 4-angled, 4-celled ; 

 s/)V«s 2, awl-shaped ; s^i'gw a simple ; /r«iY 4-celled, 

 4-lobed, 4-seeded, flattened laterally, not opening. 

 Small aquatic, herbaceous plants, with long, weak, 

 tangled stems, which are usually submerged, opposite simple entire 

 leaves, of which the upper alone float on the surface of the water, 

 and long, thread-like silvery roots, which proceed from the joints 

 of the stem, and are either attached to the soil below or are 

 suspended in the water. 



I. Callitriche (Water Star-wort). — Characters given above. 



Buxus 



Sempervirens 

 (Common Box-tree) 



I. Callitriche (Water Star-wort) 



I. C. verna (Vernal Water Star- ^ 

 wort). — Leaves in pairs, united at the ^s=g 

 base ; flowers in the axils of the leaves ; -^^ 

 carpels bluntly keeled at the back. An 

 aquatic plant, with long slender stems, 

 which send out shining roots from the 

 joints ; either growing in running 

 water, when the leaves are usually very 

 narrow, or in slagnanl wafer, when 

 the upper leaves are broader, and float 

 on the surface, crowded into a starry 

 form, the stamens being the only parts of the plant actually raised 

 above it. Streams and stagnant water ; everywhere. — Fl. May to 

 July. Annual. 



Callitriche Verna 

 {Vernal Water Star-wort) 



