86 CLASSICS OF MODERN SCIENCE 



I shall enumerate three or four real mule plants, to whose origin 

 I have been an eye-witness. 



1. Veronica spuria, described in Amoenitates Acad. vol. III. p. 35, 

 came from the impregnation of Veronic maratima by Verbena officin- 

 alis; it is easily propagated by cuttings, and agrees perfectly with its 

 mother in fructification, and with its father in leaves. 



2. Delphinium hybridum, sprung up in a part of the garden where 

 Delphinium datum and Aconitum Napellus grew together; it re- 

 sembles its mother as much in its internal parts, that is, in fructification 

 as it does its father (the Aconitum) in outward structure, or leaves; 

 and, owing its origin to plants so nearly allied to each other, it prop- 

 agates itself by seed; some of which I now send with this Disserta- 

 tion. 



3. Hieracium Taraxici, gathered in 1753 upon our mountains by 

 Dr. Solander, in its thick, brown, woolly calyx; in its stem being 

 hairy towards the top, and in its bracteae, as well as in every part 

 of its fructification, resembles so perfectly its mother, Hieracium 

 alpinum, that an inexperienced person might mistake one for the other ; 

 but in the smoothness of its leaves, in their indentations and whole 

 structure, it so manifestly agrees with its father, Leontodon Taraxacum 

 (DandeHon), that there can be no doubt of its origin. 



4. Tragopogon hybridum attracted my notice the autumn before 

 last, in a part of the garden where I had planted Tragopogon pratense, 

 and Tragopogon porrifoliiim; but winter coming on, destroyed its 

 seeds. Last year, while the Tragopogon pratense was in flower I rub- 

 bed off its pollen early in the morning, and about eight o'clock 

 sprinkled its stigmata with some pollen of the Tragopogon porrifol- 

 ium, marking the calyces by tying a thread round them. I afterwards 

 gathered the seeds when ripe, and sowed them that autumn in another 

 place; they grew, and produced this year, 1759, purple flowers yellow 

 at the base, seeds of which I now send. I doubt whether any 

 experiment demonstrates the generation of plants more certainly 

 than this. 



There can be no doubt that these are all new species produced by 

 hybrid generation. And hence we learn, that a mule offspring is the 

 exact image of its mother in its medullary substance, internal nature, 

 or fructification, but resembles its father in leaves. This is a founda- 

 tion upon which naturalists may build much. For it seems probable 



