ON HYBRIDIZATION AMONG PLANTS. 
307 
We will now pass on to the more special object that we had 
in contributing this Article to the Popular Science Review ; 
namely, to give our readers a brief resume of M. NaudnPs ob- 
servations on Hybridism, as specially set forth in his admirable 
paper,* in reply to the following questions, proposed by the 
Academy of Science : — 
1. To study vegetable hybrids with special reference to their fecundity, the 
perpetuity, or sterility of their character. 
2. In what cases are hybrids fertile of themselves ? Is their fruitfulness in 
accordance with their exterior likeness to the species from which they spring, 
or does it indicate a special affinity with reference to their origin, as has been 
remarked, for the facility of the production of these hybrids themselves ? 
3. Do hybrids, sterile of themselves, always owe their sterility to the im- 
perfection of the pollen ? Are the pistils and ovules always susceptible to 
being fertilized by a foreign pollen suitably chosen ? Is a state of imperfection 
ever appreciable in the pistils or ovules ? 
4. Do hybrids, which reproduce themselves by their own fertilization, 
sometimes preserve invariably their characters during several generations, and 
can they become the type of constant races, or do they always revert, on the 
contrary, to the forms of one of their predecessors at the end of some genera- 
tions, as recent observations seem to indicate ? 
We will follow M. Naudiffis arrangement, and adopt the 
same heads under which he arranges his reply. 
1. Sterility and Fecundity of Hybrids. — It has been long ago 
established that certain hybrids are absolutely barren, others 
are partially sterile, and some quite fertile. In fact, Herbert 
says there is no decided line of absolute sterility ; and we have 
shown that the fertility of a hybrid depends upon varying 
causes, more, in fact, upon “ constitution 33 and idiosyncracy/"’ 
than mere botanic affinity : thus, Crinum cajpense ( Amaryllis 
longifolia), an aquatic and extra-tropical plant, was crossed by 
Herbert with G. scabrum , a drier and tropical species. The 
hybrid produced proved barren for sixteen years, but at last 
produced two good seeds ! Whereas G. capense and G. jpedun- 
culatum both swamp plants, though placed in different genera 
by some botanists, produced a fertile cross. 
In order to account for the sterility of hybrids, M. Naudin re- 
marks that we must, in all probability, go to the ovules to look 
for the cause, as the pistil often presents every sign of fertility, 
while the ovules, either all, or some only, remain abortive, as 
is the case with Luff a acutangulo + cylindrica and Gucumis 
Meloni + trigonus . Moreover, in these cases, he remarks, as 
additional proof, that far more pollen grains were deposited 
on the stigmas than ovules were produced. 
* Nouvelles Lecher dies sur VHybridite dans les Vegetaux. Ann. Sc. Nat. 
XIX. p. 180. 
