152 REPORT OF THE CONFERENCE ON GENETICS 
SPECIAL OBSERVATIONS ON SOME FAMILIES OR SPECIES. 
I apply the term ‘“cross”’ to the pollination of one species by 
another species, and ‘“‘ products” to the results of such “ crosses.” 
RaNuNcULACE®.—A considerable number of crosses. _ Products : 
individuals almost isolated. Carpels well formed, but not numerous. 
CrucIFER®.—Many vernal species, provided with nectaries, much 
visited by insects. Forms of crosses numerous, and individuals often 
abundant (genera, Arabis, Nasturtium, Cardamine, Draba). Fruits often 
abortive. 
CIsTINEs®.*—Forms of crosses very numerous, giving rise to numerous 
individuals. The cross products bear the impress of the varieties from 
which they have sprung. 
VioLAcEm.—Numerous crosses; individuals abundant. Capsules pro- 
vided with seeds not very numerous. 
CARYOPHYLLE®. Dianthus.—Crosses easy; number of individuals 
very large. Capsules often malformed. 
PAPILIONACE®.— Crosses less numerous ; individuals as a rule almost 
isolated. | 
Pomace®.—The genus Sorbus gives frequent hybrids, the species 
being very distinct ; their products are rather variable, even in the same 
individual, especially in regard to the foliage. The sterile branches 
often differ very much from the fertile ones. Fructification nil, or im- 
poverished. 
Rosacex. Rosa, Rubus.—In these two genera the species are rather 
badly limited. Hybrids are formed between allied or very distant species. 
The forms of the crosses are extremely numerous, and their characteristics 
are ill-defined. The individuals resulting from crosses are relatively 
abundant. Sterility is frequent, but not absolute in these two families. 
Potentilla.—Same observations as for Rosa and Rubus, but more 
often sterile. 
ONAGRARIEH. Hpilobium.—One of the genera in which hybrids 
are very frequent. Most often the capsules contain well-formed seeds, of 
which it would be desirable to know the germinating capacity. 
UMmBELLIFER®.—By reason of precocious fertilisation, hybridisation 
is an exception in this important order. In the whole order there are 
only seventeen hybrid forms recognised, and some of them are very 
doubtful. 
SAXIFRAGACE.—Crosses numerous ; individuals abundant, and fairly 
stable in form. 
RuBIACE”.—Crosses numerous. Varieties abundant. Fertilisation 
relative. 
Composit. Jnula.—Crosses numerous ; individuals abundant. 
Senecio.—Crosses very numerous ; individuals abundant, often provided 
with well-formed but not numerous seeds. - 
Cirsiwm.—Crosses very numerous; individuals very abundant. In 
certain hybrids, C. rigens, C. hybridum, &e., the root gives rise to several 
stalks or branches. The leaves of the central stalks frequently differ 
* My eminent colleague Dr. Bornet, member of the Institute, has published, 
respecting this family, works of such importance that I could not attempt to give an 
analysis of them here. 
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