GROUP IV. PHANEROGAMIA : ANGIOSPERM.E : MONOCOTYLEDONES. 555 



crowded on the broad receptacle. The main axis of the inflorescence bears 

 whorls of branches which have a helicoid ramification. It is rather common in 

 damp spots. Damasonium stellatum, the Star-fruit, is found in ditches in the 

 South of England : it has two-seeded ovaries. 



Sagittaria sagittcefolia, the Arrowhead, has monoecious flowers with the 

 formula KB, (7:3, A GO, $ Gj^. The flowers are disposed in trimerous whorls, 

 the 6* in the upper and the ? in the lower whorls. The anthers are extrorse. 

 The ovaries, which are very numerous and one-seeded, are inserted on a fleshy 

 receptacle. Only the sagittate leaves aud the inflorescence appear above the 

 water. 



Order 4. BUTOMACEJE. Flo wersnevermonosporangiate; general 

 floral formula the same as in Alismacese ; anthers introrse ; carpels 

 distinct ; ovules numerous, with superficial placentation j embryo 

 straight or curved. 



Dutnmus umlellatus ia 

 the Flowering Bush (Figs. 

 3(50 A, 361). The flowers, 

 which have violet petals, 

 have the following for- 

 mula : KB, (73, .43 2 -f3, 

 G 3 + 3 ; they are arranged 

 in an umbellate helicoid 

 cyme at the apex of the 

 scape, which is about 3 

 feet high ; this and the 

 leaves, which are of about 

 the same length, spring 

 from an underground rhi- 

 zome. The ovules, which 

 are numerous, are borne 

 on the inner surface of 

 the carpels (Fig. 338 C) : 

 the embryo is straight. 



The other genera all 

 have a curved embryo : in 



FIG. 361. Butomus umbellats. A Flower (nat. size). 

 J3 Gynaeceum (mag.); stigmata. I Diagram: p p 

 perianth; /stamens of the outer whorl duplicate: /' 

 stamens of the inner whorl; c outer, and c' inner whorl 

 of carpels. (After Sachs.) 



Tenagocharis (Butomopsis) there are nine stamens and six carpels: in Hydro- 

 cleis there are indefinite stamens (some sterile) and six carpels : in Liuinocharis 

 both the stamens (some sterile) and carpels are indefinite. 



Sub-series. Syvcarpx. 

 Gynseceum syncarpous. 

 Gommelynales. Perianth heterochlamydeous ; 



Cohort 1. 

 seeds with starchy endosperm. 



Order 1. XYIUDACEJJ. Herbaceous 



sedge-like plants ; floral 



