332 



ORGANOGEAPHY, 



Fig. 738. Progressive developTnent of the arillode of Euonymus. a. Aril- 

 lode. /. Funiculus. 1. reiiresents the youngest seed ; 2. and 3. the 

 progressive development of the arillode; 4. the oldest and fully deve- 

 loped seed. 



Caruncules or Strophioles. — These are small irregular pro- 

 tuberances which are found on various parts of the testa. 

 They are always developed, like the arillus and arillode, subse- 

 quent to fertilization, and are accordingly not found in the ovule. 

 In the Milkwort {fig. 739), they are situated at the base or 

 hilum of the seed ; in the Asarabacca {fig. 740) and Violet on 

 the side, in a line with the raphe ; while in the Spurge, they are 

 placed at the exostome. Some writers consider these caruncules 

 as forms of the aril, of which they then distinguish four varieties, 

 namely: — 1. The true arillus, as in Nymphcea {fig. 737, a, a) ; 



2. The arillode or onicropf/lar arillus, as in Euo7iymus {fig. 738) ; 



3. The raphian arillus, as in Asarum {fig. 740); and 4. The 

 chalazal arillus, as in Epilobium {fig. 741), where the tuft of 



Fig. 739. 



Fig. 740. 



Fig. 741. 



Fiff. 739. Ovate seed of Milkwort (Poly- 

 gala), with a caruncula at its base or 



hilum. Fig. 740. Seed of Asarabacca 



(Asarum), with a caruncula on the side, which is called by some a 



raphian arillus. Fig. 741. Section of the comoseseed of Epilobium. 



The tuft of hairy processes is sometimes called a chalazal arillus. 



hairs at one end of the seed is so regarded. Other writers again 

 partially adopt these views, and detine the caruncules as little 

 protuberances occurring upon the seed, but originating inde- 

 pendently of the funiculus or micropyle, so that the caruncules 



