1864. | Botany and Vegetable Physiology. 453 
dacew, Boraginacew, Solanacew, Malvacee, Crucifere, Passifloracem, 
Cactaceew, Umbelliferee, Myrtacee, Rosacee, and Leguminose ; and he 
finds that in Dicotyledons the grains may preserve their fecundating 
property, under certain conditions, for a period varying from one to 
three years; whilst, in Monocotyledons, the period extends to six 
years. 
The parasite called Cuscuta cassythoides grows at the Cape of 
Good Hope, on a species of Lycium, probably L. Afrum. It sends out 
long line-like branches, which entwine themselves firmly round those 
of the Lycium, and after one has established itself on a new branch, 
the connecting link between it and the old stock dies away, and a new 
plant is established on its own account. 
M. Deherain finds that sulphate of lime, when introduced into 
arable land, does not assist the formation of nitrates or of ammonia, but 
that it acts by favouring the solubility of potash. According to him 
it transforms the neutral carbonate of potash into the bicarbonate 
which filters easily through the arable land. He gives detailed ex- 
periments and results in the ‘ Annales des Sciences Naturelles.’ 
In a paper on the variability of the Pear, by M. Decaisne, given 
in the ‘Annales des Sciences Naturelles,’ the author maintains that 
there is no evidence of the degeneration of our fruit trees, in conse- 
quence of their continual propagation by grafting. The facts stated by 
those who contend for degeneration may be explained in various ways, 
such as climates or soils unsuited for the particular wants of the 
varieties, bad culture, or improper grafting. Our ancient pears, so 
justly esteemed for a century or two, are still the same as they were 
at first. The Crassane, Saint Germain, Doyenné, Chaumontel, Bon- 
Chretien, &c., have lost none of their qualities. If they are neglected, 
it is only because cultivators are looking after novelties. M. Decaisne 
also maintains that it is not true that the seeds of good varieties of 
fruit when sown in ordinary soil have a tendency to go back to a wild 
state, and produce crab-fruit. He says that no example has been 
produced of a good fruit fertilized by the pollen of its own flower or 
of other flowers of the same race, having produced seeds which gave 
origin to a wild plant with crab fruit. An esteemed variety fertilized 
by pollen from a variety with sour fruit may no doubt produce fruit of 
inferior quality ; but every good variety, if it is only fertilized by it- 
self, will produce good fruit. He says that we do not find the Can- 
teloup melon returning, by being sown, to the small wild melon of 
India; nor our cauliflowers and cabbages taking on the form of the 
wild plants of the sea-shore. Species in the vegetable kingdom are 
endowed with great flexibility, the same specific type giving rise to 
races and varieties of very different aspects, but having the same mor- 
phological organization, and capable of uniting with each other by 
crossing, like the members of the same family. If we transport one 
of our races of pear to all quarters of the globe, we shall find that 
wherever it can live, it will have a tendency to put itself into harmony 
with the circumstances in which it is placed, and in course of time it 
will give origin to numerous new varieties. 
