366 PLANTS FEETILE WITHOUT INSECT-AID. CHAP. X. 



yielded 16'5 grains weight; so that the latter plants were 

 more productive than the uncovered. Professor H. Hoffmann 

 (' Speciesfrage,' 1875, p. 53) also found this species self-fertile 

 when protected from insects. 



P. vagum. Produced late in the summer plenty of seeds, which 

 germinated well. 



P. argemonoides . . . . "j According to Hildebrand (' Jahr- 



Glaucium luteum (Papaverace*) . tL^-f 



Argemone ochroleuca (Papaveraceae) . J are by no means sterile. 



Adlumia cirrhosa (Fumariacese). Sets an abundance of capsules. 



Hypecoum procumbens (Fumariaceae). Hildebrand says (idem), 

 with respect to protected flowers, that ' ' eine gute Frucht- 

 bildung eintrete." 



Fumaria officinalis (Fumariacese). Covered-up and unprotected 

 plants apparently produced an equal number of capsules, 

 and the seeds of the former seemed to the eye equally good. 

 I have often watched this plant, and so has Hildebrand, and 

 we have never seen an insect visit the flowers. H. Miiller 

 has likewise been struck with the rarity of the visits of insects 

 to it, though he has sometimes seen hive-bees at work. 

 The flowers may perhaps be visited by small moths, as is 

 probably the case with the following species. 



F. capreolata. Several large 'beds of this plant growing wild 

 were watched by me during many days, but the flowers 

 were never visited by any insects, though a humble-bee 

 was once seen closely to inspect them. Nevertheless, as 

 the nectary contains much nectar, especially in the evening, 

 I felt convinced that they were visited, probably by moths. 

 The petals do not naturally separate or open in the least ; 

 but they had been opened by some means in a certain pro- 

 portion of the flowers, in the same manner as follows when 

 a thick bristle is pushed into the nectary ; so that in this 

 respect they resemble the flowers of Corydalis lutea. Thirty- 

 four heads, each including many flowers, were examined, 

 and twenty of them had from one to four flowers, whilst 

 fourteen had not a single flower thus opened. It is there- 

 fore clear that some of the flowers had been visited by 

 insects, while the majority had not ; yet almost all produced 

 capsules. 



Linum usitatissimum (Linacese). Appears to be quite fertile. 

 H. Hoffmann, ' Bot. Zeitung,' 1876, p. 566. 



Impatient larbigera (Balsaminaceae). The fl pwers, though ex- 



