418 BOTANY [Chap. XI 



Letter 746 Thymus your view will manifestly be rendered still more 

 probable. I have never felt satisfied with H. Muller's view, 1 

 though he is so careful and admirable an observer. It is 

 more than seventeen years since I attended to Plantago, and 

 when nothing had been published on the subject, and in 

 consequence I omitted to attend to several points ; and now, 

 after so long an interval, I cannot pretend to say to which of 

 your forms the English one belongs ; I well remember that 

 the anther of the females contained a good deal [of] pollen, 

 though not one sound grain. 



P.S. — Delpino is Professor of Botany in Genoa, Italy 2 ; I 

 have always found him a most obliging correspondent. 



Letter 747 To W. Thiselton-Dyer. 



Down, Aug. 24th [1878]. 



Many thanks for seeds of Trifolium resupinatum, which 

 are invaluable to us. I enclose seeds of a Cassia, from Fritz 

 Muller, and they are well worth your cultivation ; for he says 

 they come from a unique, large and beautiful tree in the 

 interior, and though looking out for years, he has never seen 

 another specimen. One of the most splendid, largest and 

 rarest butterflies in S. Brazil, he has never seen except near 

 this one tree, and he has just discovered that its caterpillars 

 feed on its leaves. 



I have just been looking at fine young pods beneath the 

 ground of Aracliis} I suppose that the pods are not with- 

 drawn when ripe from the ground ; but should this be the case 

 kindly inform me ; if I do not hear I shall understand that 

 [the] pods ripen and are left permanently beneath the ground. 



If you ever come across heliotropic or apheliotropic aerial 

 roots on a plant not valuable (but which should be returned), 

 I should like to observe them. Bignonia capreolata, with its 

 strongly apheliotropic tendrils (which I had from Kew), is now 

 interesting me greatly. Veitch tells me it is not on sale in 

 any London nursery, as I applied to him for some additional 

 plants. So much for business. 



I have received from the Geographical Soc. your lecture,* 



1 See Forms of Flowers, Ed. II., p. 308. Also letter 744. 



2 Now at Naples. 



3 Arachis hypo^cea, cultivated for its "ground nuts." 



4 " On Plant Distribution as a field for Geographical Research." 

 Geoe;r. Soc. Proc, XXII., 1878, p. 412. 



