CHAP. IV. RESEDA LUTEA. 117 



The English-crossed plants, though so superior in productive- 

 ness, were, as we have seen, decidedly inferior in height and 

 weight to the self-fertilised, and only equal to, or hardly superior 

 to, the intercrossed plants. Therefore, the whole advantage of a 

 cross with a distinct stock is here confined to productiveness, and 

 I have met with no similar case. 



. KESEDACEJ3. RESEDA LUTEA. 



Seeds collected from wild plants growing in this neighbour- 

 hood were sown in the kitchen- garden ; and several of the 

 seedlings thus raised were covered with a net. Of these, some 

 were found (as will hereafter be more fully described) to be 

 absolutely sterile when left to fertilise themselves spontaneously, 

 although plenty of pollen fell on their stigmas ; and they were 

 equally sterile when artificially and repeatedly fertilised with 

 their own pollen; whilst other plants produced a few spon- 

 taneously self-fertilised capsules. The remaining plants were 

 left uncovered, and as pollen was carried from plant to plant by 

 the hive and humble-bees which incessantly visit the flowers, 

 they produced an abundance of capsules. Of the necessity of 

 pollen being carried from one plant to another, I had ample 

 evidence in the case of this species and of It. odorata ; for those 

 plants, which set no seeds or very few as long as they were 

 protected from insects, became loaded with capsules immediately 

 that they were uncovered. 



Seeds from the flowers spontaneously self -fertilised under the 

 net, and from flowers naturally crossed by the bees, were sown on 

 opposite sides of five large pots. The seedlings were thinned as 

 soon as they appeared above ground, so that an equal number 

 were left on the two sides. After a time the pots were plunged 

 into the open ground. The same number of plants of crossed 

 and self-fertilised parentage were measured up to the summits 

 of their flower-stems, with the result given in the following 

 table (XXXV.). Those which did not produce flower-stems were 

 not measured. 



The average height of the twenty-four crossed plants is here 

 17 17 inches, and that of the same number of self- fertilised plants 

 14 61; or as 100 to 85. Of the crossed plants all but five 

 flowered, whilst several of the self-fertilised did not do so. The 

 above pairs, whilst still in flower, but with some capsules already 

 formed, were afterwards cut down and weighed. The crossed 



