CROSSINGS MADE AT NATURAL HISTORY MUSEUM, PARIS. 219 
the power of fructification. These crossings, which may be called cross- 
ings of the second degree, have generally succeeded much better than 
those made direct between specific types, that is to say, than the crossings 
of the first degree (see Nos. 7 to 12). 
I may be permitted to express a regret—it is that in many cases the 
result of our trials has been compromised by accidental causes (excessive 
drought in 1893 and in the autumn of 1895; cyclone with hail at the end 
of July, 1896), and also and especially by indiscreet curiosity and some- 
times by the wilful destruction of visitors (the Jardin des Plantes is open 
to the public), and even of certain of our gardeners. 
SUGGESTIONS. 
It would be interesting, we think, if it were only from the historical 
point of view, to endeavour to reconstitute certain plants which are 
currently considered as hybrids, but without certain proof of such origin. 
It would be a question of establishing this origin in a precise and 
indisputable manner, that is to say, to do for these plants that which 
M. Lemoine, of Nancy, and I have done for the Varin Lilac (Syringa 
dubia) in reconstituting it by means of crossings of the Persian Lilac 
with the common Lilac (see No. 23). 
The Conference could perhaps organise a series of researches in this 
direction. I make the suggestion with that object. 
By way of indication I give the following list, necessarily incomplete, 
of the plants I have in view. This short list comprises mainly woody 
species, with which I occupy myself more particularly. 
List oF PLANTS CONSIDERED TO BE HYBRIDS, WHICH IT WOULD BE 
INTERESTING TO RECONSTITUTE BY CROSSING. 
Amygdalus persicoides (Duham.) Juglans Vilmoriniana (Carr.). 
=A. Persico-Amygdala (Daléch.). | Prunus cerasifolia (Hort.) 
Aisculus rubicunda (D.C.). =Padus greea (Desf.). 
Berberis Neuberti (Hort.) | Pyrus malifolia (Spach). 
=B. ilicifolia (Hort.). Pyrus Bollwylleriana (D.C.). 
Berberis stenophylla (Moore). | Ribes Gordonianum (Lem.). 
Cerasus Fontanesiana (Spach) _ Ribes intermedium (Billiard 1867). 
=Prunus greca (Desf.). Robinia Decaisneana (Carr.). 
Crategus Oxyacantho-germanica _, Rosa alba (L.). 
(Gillot ) _ Rosa Fortuneana (Lindl.). 
=C. grandiflora (K. Koch) Rosa Hardyi (Cels). 
=C. lobata (Bosc.) Rosa hybrida (Schleich). 
=Mespilus Smithii (D.C.). Rosa Noisettiana (Red.). 
Cytisus Adami (Poit.). Rubus nobilis (Rgl.). 
Dianthus semperflorens (Hort.). | Sorbus hybrida (L.). 
Juglans hybrida (Hort.) | Spirea Van Houttei (Briot). 
=Juglans pyriformis (Carr.). &e., &e. 
