REPORT ON THE BOTANY OF JUAN FERNANDEZ AND MASAFUEK \. 29 



the same structure in both, with the noteworthy physiological difference that the latter 

 exuded a viscous substance by which they clung together in clusters. This provision, as 

 we learn from Kerner's admirable observations, is only made where cross fertilisation is 

 effected by insects, being unknown iu anemophilous flowers. So it may be assumed that 

 there is cross fertilisation of the expanded flowers of different plants, and it is known from 

 actual observation that self-fertilisation takes place in the underground closed flowers. 

 The cultivated plants produced underground fruits, which were as large as those repre- 

 sented in St Hilaire"s figure, but Dr Grisebach does not state whether another generation 

 was raised from the seed. 



W ith regard to the purpose of these underground seeds, Dr Grisebach hints that it may 

 be to ensure the reproduction of the plant in a locality where the prolonged droughts might 

 otherwise jeopardise its existence. Cardamine chenopodifolia is a monocarpic, or what is 

 more commonly called an annual plant, and the buried seeds would retain their vitality 

 long after the parent had perished and the seed produced above ground had been dispersed 

 or destroyed ; and then when the rains returned the buried seeds would germinate. But 

 this explanation is hardly sufficient, if we take into account the natural habitat of the 

 plant. St Hilaire says: "Nascitur in pascuis maritimis ; " and on Gibert's label in the 

 Kew Herbarium, as already mentioned, there is the memorandum : " Croit jusque dans 

 l'eau salee." Therefore it would seem more probable that the purpose is to prevent the 

 seed being carried away by the water. We find another provision for this purpose in 

 many of the Mangroves [Rhizophora spp. &c), the seeds of which germinate while still 

 in the seed-vessel attached to the parent plant ; and the thick, heavy radicle goes on 

 elon»atino- until its combined weight and length brino- it down to the mud, in which it 

 soon takes a hold, and the plumule begins to grow, and the connection with the parent is 

 severed. On the other hand, many other plants exhibit the same phenomenon, and some 

 of them grow in quite dry localities ; so it is not safe to generalise as to the advantages 

 enjoyed by them therefrom. In fact, it is a subject awaiting thorough investigation, for 

 doubtless some plants have retained the faculty after they have ceased to derive any 

 benefit from it. Seeds thus sunk in the earth are not only protected from drought or 

 water, as the case may be, but also from birds and many graminivorous animals that do 

 not burrow. 1 



Cardamine flaccida, Ch. et Schl. 



Cardamine fiaceida, Ch. et SchL in Linnapa, i. p. 21. 



Cardamine honariensis, Pers., Synopsis PL, ii. p. 195; DC, Prodi'., i. p. 150. 



Juan Fernandez. Douglas; Moseley, 



There is some doubt whether the Juan Fernandez plant be really Cardamine fiaceida, 

 inasmuch as it is to us uncertain whether that is a distinct species or merely a form of 

 1 For further particulars on this sulject see Dyer in Nature, xvii., 1878, p. 41G. 



