STUDIES IN THE CRUCIFERÆ. 129 
are long since unanimously conceded to be aggregates, while 
those of Tournefort are for the most part found acceptable 
still. 
Linneus, it is true, chose a generic type; but his criteria 
of affinity were empirical. He judged of relationship by 
techniealities of flower and fruit, ignoring habital resem- 
blances. His genus Erysimum well illustrates this. He 
chose for its type precisely the species which Tournefort had 
done; but he gathered things into the genus according to 
technicalities of the siliques alone. His type was a plant 
with somewhat angular pods quite erect and parallel with 
the stem or rachis. It is as if, having jotted down the salient 
fruit characters of his type, he had straightway gone counter 
to his own doctrine about allowing a genus to fix its own 
character, by admitting to this one such species as came 
nearest responding to the demands of the artificial character, 
ignoring those habital marks which furnish the best clew to 
natural relationship. This is really making the character 
determine the genus, not the genus the character. And the 
result, in this instance, has been that the four species of his 
genus Erysimum are, in spite of their approximate agreement 
as to angular and erect pods, representatives of about four 
genera, according to the judgment of posterity. One must 
be the type of Erysimum. The second is known as the type 
of Barbarea. The third is the monotypic genus Alliaria, 
while the fourth goes into Linneus’ own genus Cheiranthus. 
The type-species of Erysimum, whether one reckon genera 
from Tournefort or from Linnsus, is Erysimum officinale, 
Linn. Here is given an opportunity for any one among the 
champions of priority to explain why in even the most ap- 
proved of recent books and catalogues this, the head and 
front of Linneeus’ genus Erysimum is referred to Sisymbrium, 
and yet a pretended Linnean Erysimum is retained. If the 
very type of Erysimum be a Sisymbrium, then there is no 
Erysimum at all. This is the doctrine of all of us, advocates 
of priority. Why are some of us so openly at war with our 
