II MALVACE.E 123 



or less triangular spaces, enclosed by the under side of the 

 leaf, the walls of the nerves, and a fringe of long hairs. 

 Attention to these was first called by Lundstrom,^ 

 who regards them as abodes — "domatia" — for mites. 

 That they are not pathogenic, he proved by growing 

 seedlings and carefully keeping mites away. This was, 

 however, no easy matter, for the mites lay their eggs in 

 the fruit, in which indeed there is, he considers, a special 

 cavity prepared fgr the purpose. In this way the 

 mites develop pari passu with the young plant. During 

 the day the mites remain at home in the domatia, but 

 at night, and sometimes during dull days, they run 

 about all over the leaves, which, 

 however, they do not appear to 

 attack. He suggests — and the 

 theory, though not proved, is 

 probable — that the mites are 

 useful in eating the spores of 

 fungi, which might otherwise 

 grow on and injure the leaves. 

 M. Areschoug thinks he has ob- 

 served that when the mites are _ 

 numerous the leaves are specially puj, 67.— Lime embryo. 

 large and healthy. In certain 

 genera some species have domatia and others not ; in 

 the former the leaves are generally smooth, and in the 

 latter protected by hairs. Similar domatia occur on 

 the leaves of many other forest trees, as the Oak, Elm, 

 Sycamore, Alder, Holly, etc. 



The seedlings of the Lime (Fig. 68) are interesting ^ 

 and peculiar. The cotyledons are leafy, and palmately 

 five-lobed, somewhat like a hand. This form is very rare, 

 if not unique. The seeds are obovoid ; the embryo is at 

 first straight, but ultimately follows the curvature of the 

 seed (Fig. 67). If the leaf grew continuously in a hollow 

 form, it is obvious that it could not unfold without 

 rupturing itself. If any one will take a common tea- 



1 Nova Acta Eeg. Soc. Sci. Upsala, ser. 8. xiii. fasc. 2 (1887). 

 * See Avebury (Lubbock), On Seedlings, i. p. 282. 



