Robert Sharrock was a fellow of New College, Oxford. Both the Bobarts were professional botanists, the father was author of a Catalogue of the plants in the Hortus Medicus at Oxford, and the son was afterwards Curator of the Oxford Garden.
[4] Mém. Ac. roy. des Sci. for 1719 (1721), p. 59.
[5] Amoen. Acad., 1789, vol. 6. I do not know whether attention has been called to the curious mistake which Linnaeus makes in the course of this argument. He cites the differences between the Mule and the Hinny in illustration of his thesis, pointing out that the Mule is externally more like a horse and the Hinny more like an ass. This, he says, is because the Mule has the horse for a father, and the Hinny the ass, thus inverting the actual facts!
[6] Proc. Washington Ac. Sci., 1909, XI, pp. 17-26.
[7] J. W. Tutt, in Ent. Rec., 1909, XXI, p. 185.
[8] E. Lehmann (Bull. l'Herb. Boissier, Ser. 2, VIII, 1908, p. 229) has published an admirable paper on the interrelationships of these species and has instituted cultural experiments which will probably much elucidate the nature of their specific distinctness. As regards the existence of intermediate forms he comes to the conclusion that two only can be so regarded. The first was described by Kuntze from specimens found on a flower-pot on board a Caspian steamer, from which Lehmann proposes the new specific name Siaretensis. This comes between polita and filiformis, a close ally of Tournefortii. The other, which combines some of the features of both polita and Tournefortii, was found in the province of Asterabad.
[9] In Cambridgeshire for example vespertina is common but diurna is absent. Whether this absence is connected with the general presence of chalk I cannot say. When introduced artificially diurna establishes itself, for a time at least, without any apparent difficulty and occasionally escapes from the garden on to the neighbouring roadside.
[10] Conceivably however it may be a segregated combination. For an account of this plant see Boissier, Voy. Bot. Midi de l'Espagne, 1839, II, 722.
[11] A discussion of this subject with references to literature is given by Rolfe, in an excellent paper on "Hybridisation viewed from the standpoint of Systematic Botany" (Jour. R. Hort. Soc., XXIV, 1900, p. 197). He concludes: "The simple fact is that the two plants (L. diurna and vespertina) are thoroughly distinct in numerous particulars, and affect such different habitats that in some localities one or the other of them is completely wanting. But when their stations are adjacent they hybridise together very readily, and it is here that these intermediate forms occur which have puzzled botanists so much." The same paper contains valuable information concerning several cognate illustrations.
[12] In only two cases have I seen such plants (both females) completely sterile.