FKOM AN OLD STANDPOINT. 



199 



these into genem, while the accidents " aforesaid " discriminated 

 the genera into species." Doctor Guppy estal)Mshes his theory by 

 the following arguments : — 



1st. That the genus or sub-genus which contains more than any 

 other the characters of an order, and appears thus to be the parent 

 of its other genera, is the very one which is most widely distributed 

 (of which phenomenon he, however, only actually cites two examples). 



2nd. That amono; 23 orders and sub-orders that have been examined 

 we get a result in a descending scale such as the theory would lead 

 us to expect — namely that 92 per cent, of the tribes, 11 per cent, of 

 the genera, and only 1 per cent, of the species are common to the 

 Old World and the Xew. 



3rd. That since the conditions under which land plants live differ far 

 more amongst themselves than those under which fresh-water plants 

 exist, we should expect to find far more species of land orders than 

 of fresh-v/ater ones ; and, as a fact, ^ve find ten times as many of the 

 former as of the latter. 



4th. That where the agencies of dispersal (currents, winds, and 

 birds) have their fullest play in maintaining original species, there 

 the number of strange species found is smallest. 



The case is very strong against the common theory of dispersal of 

 genera from single centres, which other arguments of the author 

 show to be untenable ; but he does not overthrow the view that 

 every genus, and perhaps every species, was originated in one or 

 more of its present abodes. If the species and genera of each order 

 are the result of differentiation, we should expect to see them 

 forming hybrids between themselves ; whereas even the species will 

 not do this naturally — and to bring it about artificially is no easy 

 task — all the proper stamens of the fruiting flower having first to be 

 cut away, for if any of its own pollen be at hand its stigm;i will 

 receive and assimilate this by preference and yield a flower lik 

 itself."^ In an article written a year ago from Palestine to the 

 Gardencrfi Chronicle f by our fellow-member Mr. Arthur Sutton, he 

 described the abundance and beauty of two plants that grow side by 

 side in many parts of Palestine — the Anemone coronaria and the 

 llannnculus Adaticui, The form of the flowers is, he says, the same, 



* Chambers's Encyclopjiedia, Hybrids. 

 t For April 28t]i, 1906. 



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