500 



DICOTYLEDONES. 



jection (6 vascular bundles indicate that the number 6 is prevalent 

 here, as in Asm-urn) ; 6 stamens (Fig. 540 a), with the dorsal por- 

 tion turned upwards, are united with the short style to form a 

 stylar column ; they are placed quite beneath the 6 commissural 

 stigmatic rays, which arch over them as short, thick lobes. 

 Protogynous ; POLLINATION is effected in Arist. clematitis by small flies ; these 

 enter the erect unfertilised flower through the tube (Fig. 540 A, I) without 

 being prevented by the stiff, downwardly-turned hairs which line the tube and 

 prevent their escape ; they find the stigma (n) fully developed, and may pollinate 

 it with the pollen they have brought with them. The stigmas then straighten 

 and wither (B, n), the anthers open, and the flies may again be covered with 

 pollen ; but the hairs which blocked up the tube do not wither until the 

 anthers have shed their pollen, and only then allow the imprisoned flies to 

 escape and effect cross-pollination. Prior to pollination, the flowers stand 

 erect, but after this has taken place they become pendulous, and the perianth 

 soon withers. A. sipho (Pipe-flower), another speciee, is a climber, and often 

 grown in gardens ; it has only one row of accessory buds in the leaf-axils. 200 

 species ; chiefly in S. Am. OFFICINAL : the rhizome of Aristolochia serpentaria 

 (N. Am.). 



Order 2. Santalaceae. Parasites containing chlorophyll, which, by the help 

 of peculiar organs of suction (haustoria) on their roots, live principally on the 

 roots of other plants. Some are herbs, others under-shrubs. The regular, 

 most frequently -flowers have a simple perianth, which is gamophyllous, 3- or 

 5-partite with the segments valvate in the bud, and a corresponding number 

 of stamens opposite the perianth-leaves. In the inferior ovary there is a 

 free, centrally placed, often long and curved placenta with three ovules (one 

 opposite each carpel) ; these are naked, or in any case have an extremely insig- 

 nificant integument. Fruit 

 a nut or drupe. Seed 

 without testa. Endosperm 

 fleshy. 225 species; chiefly 

 in the Tropics. Thesium, a 

 native, is a herb with scat- 

 tered, linear leaves and 

 small 5-merous flowers (P5, 

 A5, G3) in erect racemes; 

 the subtending bracts are 

 displaced on the flower- 

 stalks. Fruit a nut. Osyris 

 (dioecious shrub ; 3-rnerous 

 flowers) is another Europ- 

 ean genus. Santahim al- 

 bum, which grows in E. 

 Ind., yields the valuable, 

 scented Sandal-wood, the 



FIG. 6<Jl. A fiuit of Myiodevdion Iradiystacliyum 

 (slightly mag.) germinating on a branch. 



oil of which is used medi- 

 cinally. Quinchamalium. 



