116 JOUBXAL OF THE Er.YAL HOBTICULTUEAL SOCIETY. 
Hungarr and Bavaria lo Hambnrg, and more recently became so serious 
a pest in Sonth Africa that strenuons laws have had to be enforced for its 
extirpation. In onr own common Burdock (Arctium Lajjpa, L. i the 
involncral bracts become hooted and woody in the fruiting stage, so as to 
adhere to the for of animals or the clothes of man : but such is their 
strength that they generally tear themselves free, so that the plant 
springs back and the fruits are jerked away. The calyx of the Bur- 
marigold \Bidem tripartita. L.u one of our British Composite, is repre- 
sented by from two to six strongly barbed bristles : the calyx of some 
species of Myosotis is covered with hooks : and that of the rosaceous genera 
Agriinonia and Ac^na has a circlet of stiff recurved bristles at the apex 
of the fruit. A most interesting form of burr is that of the British Herb 
Benet {Geurn urbanum. L.). In the flower stage each carpel ends in a 
style which, at first straight, develops a double kink. In the fruit 
the apical portion breaks away, leaving the kink as a sharp, hard 
hook. By far the greater number of cases of hook-bearing fruits are 
those in which the hooks are on the pericarp. The achenes of the 
Com Crowfoot {Banunculiis arvensis, L.), the four nutlets of the 
boraginaceous Houndstongue {CynogJossum), the bicarpellate fruits 
of the Woodruff (Asperula\, Bedstraws, such as Cleavers (Galium 
Aparine, L. I and Madder {Bmhia peregrina, L. ) among Eubiaceae. and the 
siliqua of the cruciier Bunios are examples from widely different orders. 
Prickly fruits are not very numerous among L^uminosae ; but Mimosa 
asperata, L., and several species of Medic^ago, such as M. truncatula, 
Ggertn., and M. rigidul-a, Desr., are cases in point. Among UmbeUiferae 
such structures are common, as the popular name Bur-parsley wit- 
nesses. The genera Caucalis, Sanicula, and Daucus may be specially 
cited as examples. In the Carrot {Daucm Carota, L. | the secondary 
peduncles all bend inwards after fertilisation until the fruits are ripe, 
when they bend out again, so that the burred fruits may come in 
contact with passing animals. Xo order, however, is so remarkable in 
the production of hooks as that small, mainly African, group the 
Pedaliaceae. Pedaliuwi murex, L., has a calthrops-hke fruit with rigid, 
straight spines, which would attach themselves only too cruelly to the 
soles of the feet of any animal treading on them. The formidable 
curved hooks, one at the apex of each of the two carpels, resembling 
manunoth tusks in the American genus Marty nia, fasten themselves 
firmly, as we can weU imagine, in the fleece of any passing animal. 
But the mos : ; s in appearance of the whole group is the Grapple 
Plant (Harp J. . : /i procumbem, DC). This fruit, a native of South 
Africa, is surrounded by twelve or more radiating arms, each ending in 
two strong recurved hooks, and having several similar hooks along its 
sides. It is blown about over the dry veldt of the Transvaal and the 
Orange Free State, and buries itself firmly into the hoof of any antelope 
that may tread upon it, driving the animal mad with the pain. It is 
even said to sometimes prove fatal to the Hon, the animal, in endeavouring 
to tear the instrument of torture out of its skin, only making matters 
worse by getting it into its mouth. 
As has been already said, the chief cases of adaptation for carriage 
within the bodies of animals are succolent structures. It is. as might 
