614 Sir John Luhhoch [Feb. 18, 



divided into two classes, those in which the fruits are provided with 

 hooks, and those in which they are sticky. To the first class belong, 

 among our common English plants, the Burdock (Lapjpa, Fig. 14 a), 

 Agrimony (Agrimonia, Fig. 14 h) ; the Bur Parsley {Gaucalis, Fig. 

 14 c) ; Enchanter's Nightshade (Circcea, Fig. 14 d) ; Goose Grass or 

 Cleavers (Galium, Fig. 14 e), and some of the Forget-me-Nots (Myosotis, 

 Fig. 14/). The hooks, moreover, are so arranged as to promote the 

 removal of the fruits. In all these species the hooks, though 

 beautifully formed, are small ; but in some foreign species they 

 become truly formidable. Two of the most remarkable are represented 

 below, — Martynia prohoscidea (Fig. 15 6) and Harpagophyton procum- 

 hens (Fig. 15 a). Martynia is a plant of Louisiana, and if its fruits 

 once get hold of an animal it is most difficult to remove them. 

 Harpagophyton is a South African genus. The fruits are most 

 formidable, and are said sometimes even to kill lions. They roll about 

 over the dry plains, and if they attach themselves to the skin, the 

 wretched animal tries to tear them out, and sometimes getting them 

 into its mouth perishes miserably. 



The cases in which the diffusion of fruits and seeds is effected by 

 their being sticky are less numerous, and we have no well-marked 

 instance among our native plants. The common Plumbago of South 

 Europe is a case which many of you no doubt have observed. Other 

 genera with the same mode of dispersion are Plttosporum, Pisonia, 

 Boerhavia, Siegeshechia, Grindelia, Drymaria, &c. There are com- 

 paratively few cases in which the same plant uses more than one 

 of these modes of promoting the dispersion of its seeds, 'still there 

 are some such instances. Thus in the Common Burdock the seeds 

 have a pappus, while the whole flower-head is provided with hooks 

 which readily attach themselves to any passing animal. Asterotlirix, 

 as Hildebrand has pointed out, has three provisions for dispersion : 

 a hollow appendage, a pappus, and a rough surface. 



But perhaps it will be said that I have picked out special cases ; 

 that others could have been selected, which would not bear out, or 

 perhaps would even negative, the inferences which have been indicated ; 

 that 1 have put the cart before the horse ; that the Ash fruit has not 

 a wing in order that it may be carried by the wind, or the Burdock 

 hooks that the heads may be transported by animals, but that 

 happening to have wings and hooks these seeds are thus transported. 

 Now doubtless there are many points connected with seeds which are 

 still unexplained ; in fact it is because this is so that I was anxious to 

 direct attention to the subject. Still I believe the general explanations 

 which have been given by botanists will stand any test. 



Let us take for instance seeds formed on the same type as that of 

 the Ash — heavy fruits, with a long wing, known to botanists as a 

 Samara. Now such a fruit would be of little use to low herbs, which, 

 however, are so numerous. If the wing was accidental, if it were not 

 developed to serve as a means of dispersion, it would be as likely to 

 occur on low plants and shrubs as on trees. Let us then consider 



