THE ANGIOSPERMAE 1247 



4. Ring in form of a disc in Rhatnmis, Thea 



and Rihes. 



5. Ring of club-like upgrowths from the disc 



in Xanthoceras. 



6. In perigynous flowers the nectary either 



forms a thickened rim to the floral cup 

 {Akhemilla, Scleranthus), or it may 

 form an interior zone of the cup in 

 Prunoideae and Cactaceae. 



(r) Tubular. A somewhat heterogeneous class. 



Examples: i. Bauhinia purpurea. Nectary takes the 



form of a spur sunk in the pedicel and 

 lined with secretory cells. 

 2. Cristatella erosa (Capparidaceae). Nectary 

 takes the form of an open tube rising 

 from the receptacle alongside the 

 ovary. 



Ovarial Type, (a) The carpel walls themselves secrete nectar. 

 Examples : i . At the apex in Androsace. 



2. At the base in Gentiana and Clethra. 



3. In depressions in the lateral walls in Caltha. 



4. All over the free surface of the carpels in 



Tofieldia palustris and Sarracenia. 



5. In the furrows between the carpels in 



Tofieldia calyculata and Ornithogahim. 



(b) The nectaries may form processes from the carpels. 



Example: The nectary forms a cup made up of united 

 scales, around the base of the ovar>^ in Convolvulaceae. 

 It is a difficult matter to decide, in some cases, 

 whether these outgrowths from near the base of the 

 ovary should be classed as toral or ovarial; nor is it of 

 great importance, 

 (f) The nectaries may be formed in the septa of syncarpous 



ovaries. This occurs exclusively in Monocotyledons. 



Examples: Septal nectaries are found throughout the 

 Liliales and in the Musaceae and its related families. 

 There is a slit in each septum lined with secretory 

 cells. The slit opens at the top of the ovary and from 

 this opening the nectar issues and flows down the 

 outside (Fig. 1201). In Allium an open canal connects 

 with the top of the nectary slit and conducts the nectar 

 to the base. 



