38 THE HISTOLOGICAL DISTRIBUTION [CH. 



The mesophyll, he considers, to be the usual, and, perhaps, more primitive 

 seat for anthocyanin. 



As regards the distribution in steins, we have the work of Berthold 

 (64) and Buscalioni & Pollacci (17). Two types of distribution can 

 be recognised: 



1. Anthocyanin in the epidermis. Ex. Gentiana, some Labiatae 

 (Berthold, 64), some Solidago and Aster spp. 



2. Anthocyanin in subepidermal assimilating cells. Ex. Alsinaceae, 

 Papilionaceae and Convolvulaceae. 



The histological distribution in petals has been investigated by 

 Hildebrand (30), Koschewnikow (40), Mliller (61) and Buscalioni & 

 Pollacci (17), and in anthers by Chatin (34). In the corolla, anthocyanin 

 is chiefly located in the epidermis, either upper or under, or both, though 

 its appearance in the subepidermal and inner tissues is by no means 

 uncommon. The following table, selected from Buscalioni & Pollacci's 

 (17) records, gives an idea of the relative frequency with which pigments 

 are formed in the various regions of the corolla and perianth. 



6 I I. 



S 4 'a 

 s ? 



^ M '&, 



3 P FM 

 1 



2 Lamium purpureum + + ... ... + + 



3 

 4 

 5 



6 Tropaeolum ... ... ... + 



7 Magnolia + ... ... + 



8 Dianthus + ... ... + 



9 Dielytra spectabilis + ... ... + 



10 Hibiscus + ... ... + 



11 



12 Tulipa + + 



13 Camellia ... + ... ... + 



14 



15 Clerodendron + ... ... + 



16 Corydalis bulbosa + ... ... + 



17 Azalea indica + ... + ... + ... + 



18 Muscari comosum + ... + ... 4 r ... + 



19 Dendrobium tirsiflorum ... + ... + + + ... + 

 20 



21 

 22 

 23 

 24 

 25 

 26 



15 



