142 Mr Burkill, On the Fertilisation of some [Feb. 12, 



(2) On the evidence as to the extent of Earth movements and 

 its hearing upon the question of the cause of glacial conditions. 

 By the President. 



[Publication deferred till next number.] 



(3) On the Fertilisation of some Species of Medicago L. in 

 England. By I. H. Burkill, B.A., Gonville and Caius College. 



Historical. The explosive mechanism found in the flower of 

 Medicago has long been known. A. P. de Candolle^ considered 

 it an outcome of the maturity of the flower whereby the stigma 

 was spontaneously pollinated. Hildebrand ^ was the first to show 

 how it had for an object the fertilisation of the flower by insects. 

 In the succeeding year Delpino ^ and G. Henslow * both published 

 papers on the subject. Delpino advanced our knowledge by 

 locating the explosive force, and Henslow noted that the Hive 

 bee {Apis mellifica L.) does not explode the flower ; at the same 

 time he communicated an observation made by Charles Darwin 

 on the fertility of M. lupidina in the absence of insect-visitors. 

 Urban and Hermann Mliller have also studied this genus. Urban® 

 attributes the work of fertilisation to bees, and at variance with 

 Hildebrand states that the flower of M. sativa is not fertile if 

 allowed to remain unexploded. And in the year in which the 

 last was published appeared Miiller's description of the flower ; to 

 him we owe lists of visitors to three species.® 



The species here concei^ned all belong to Seringe's ^ section 

 Lupularia, or to Urban's ^ two sections Lupularia and Falcago. 

 Urban following Doll® has united, not without some justification, 

 under the name of M. sativa three species — M. sativa L., M. fal- 



^ Physiologie, ii. p. 548. Paris, 1832. 'Certaines corolles contribuent meme 

 d'une maniere indirecte a la fecondation :...lorsque leur di^veloppement s'ach^ve, ces 

 crochets (referring to the processes of the alae in Indigofera and Medicago) se 

 detachent, la carene, n'etant plus fix(?e, se d^jette avec ^lasticite, et imprime aux 

 faisceaux des diamines une secousse qui determine la chute du pollen.' 



2 Ueber d. Vorrichtungen an einigen Bliithen zur Befruchtung durch Insekten- 

 hiilfe. Bot. Zeitung, xxiv. p. 71, 1866. 



^ Sugli Apparecchi della Fecondazione nelle Piante antocarpee (Fanerogame). 

 Firenze 1867. Reviewed by Hildebrand. Bot. Zeitung, xxv. p. 283, 1867. 



* Notes on the structure of Medicago sativa as apparently affording facilities for 

 the intercrossing of distinct species. Journ. Linn. Soc. (Bot.) ix. p. 327, 1867, and 

 Notes on the structure of Indigofera... with additional notice of Dr Hildebrand's 

 paper. Journ. Linn. Soc. (Bot.), ix. p. 355, 1867. 



5 Prodromus einer Monographie d. Gattung Medicago L. Verhandl. d. Bot. 

 Vereins d. Provinz Brandenburg, xv. p. 1, 1873. 



•^ (1) Die Befruchtung d. Blumen durch Insekten, Leipzig 1873, p. 225. (2) 

 Weitere Beobachtungen ii. Befruchtung d. Blumen durch Insekten. Verhandl. d. 

 Naturhist. Vereins d. preuss. Rheinlands u. Westfalens, xxxvi. p. 252, 1879. (3) 

 Alpenblumen, Leipzig, 1881, p. 248. (4) The Fertilisation of Flowers translated by 

 D'Arcy Thompson, London, 1883, p. 175 (no additions here to the German of 1873). 



'^ De Candolle's Prodromus, ii. p. 172, 1825. 



^ Loc. cit. 



s Rheinische Flora. Frankfurt, 1843, p. 802. 



