374 BOTANY [Chap. XI 



Letter 696 man how he could find out what was known on various 

 biological points in our plants, and I answered that I knew 

 of no such book, and that he might ask half a dozen botanists 

 before one would chance to remember what had been pub- 

 lished on this or that point. Not long ago another man, who 

 had been experimenting on the quasi-bulbs on the leaves of 

 Cardamine, wrote to me to complain that he could not find 

 out what was known on the subject. It is almost certain 

 that some early or even advanced students, if they found in 

 their Flora a line or two on various curious points, with 

 references for further investigation, would be led to make 

 further observations. For instance, a reference to the viscid 

 threads emitted by the seeds of Compositae, to the apparatus 

 (if it has been described) by which Oxalis spurts out its 

 seeds, to the sensitiveness of the young leaves of Oxalis 

 acetosella with reference to O. sensitiva. Under Lathy rus 

 nissolia it would [be] better to refer to my hypothetical 

 explanation of the grass-like leaves a than to nothing. Under 

 a twining plant you might say that the upper part of the 

 shoot steadily revolves with or against the sun, and so, when 

 it strikes against any object it turns to the right or left, as 

 the case may be. If, again, references were given to the 

 parasitism of Euphrasia, etc., how likely it would be that 

 some young man would go on with the investigation ; and 

 so with endless other facts. I am quite enthusiastic about 

 your idea ; it is a grand idea to make a Flora a guide for- 

 knowledge already acquired and to be acquired. I have 

 amused myself by speculating what an enormous number 

 of subjects ought to be introduced into a Eutopian 2 Flora, 

 on the quickness of the germination of the seeds, on their 

 means of dispersal ; on the fertilisation of the flower, and 

 on a score of other points, about almost all of which we are 

 profoundly ignorant. I am glad to read what you say about 

 Bentham, for my inner consciousness tells me that he has 

 run too many forms together. Should you care to see an 

 elaborate German pamphlet by Hermann Muller 3 on the 



1 No doubt the view given in Climbing Plants, p. 201, that L. nissolia 

 has been evolved from a form like L. aphaca. 



2 A mis-spelling of Utopian. 



3 Verhand. d. Nat. Ver. f. Pr. Rh. u. Wesfal, Jahrg. XXV.: see 

 Fertilisation of Orchids, Ed. II., pp. 74, 102. 



