April 13, 19 16] 



NATURE 



143 



may be sterile when pollinated with its own 

 pollen, it yields an abundant crop if pollinated 

 with the pollen of certain other varieties. Hence 

 it is of considerable economic importance to dis- 

 cover which varieties serve best for mutual cross- 

 pollination. 



Mr. Cecil H. Hooper has been engaged in the 

 study of this subject for some years, and he pub- 

 lished a short time ago a summary of the results 

 of observations made by others and himself on the 

 pollination of apples, pears, plums, and cherries. 



The list of self-sterile apples is surprisingly 

 large. It includes Lane's Prince Albert, Bis- 

 marck, Annie Elizabeth, Warner's King, Glad- 

 stone, Lady Sudeley, James Grieve, and Cox's 

 Orange Pippin (rarely self -fertile). 



It is to be observed, however, that, as indi- 

 cated in the case of Cox's Orange Pippin, self- 

 sterility is by no rtieans absolute in all these 

 varieties. This, although of no particular im- 

 portance practically — for a poor setter no less than 

 a completely self-sterile variety requires to be 

 planted with a variety the pollen of which causes 

 it to set fruit freely — is nevertheless significant 

 from a scientific point of view. It means prob- 

 ! ably that some link in the chain of chemical 

 I changes pre-requisite for the germination of the 

 I pollen tube on the stigma and its growth in the 

 j style is missing, rather than an inability of the 

 sexual nuclei to unite with one another. Thus 

 1 it is known that the absence of a particular kind 

 I of sugar on the stigmatic surface may suffice for 

 the suppression of the germination of a pollen 

 j tube. Hence it is most desirable that this 

 problem of sterility of fruit trees should be 

 studied more minutely than has been the case up 

 to the present. The pioneer field work has been 

 ■done fairly thoroughly ; it is now time for the 

 physiological botanist to intervene. He, unfor- 

 I tunately, is so sequestered in his laboratory that 

 he rarely discovers even the existence of the 

 ' "Stimulating problems which modern horticulture 

 tiers for elucidation. 

 The establishment of horticultural research 

 rations at Merton, Wisby, and Long Ashton 

 i^ives ground, however, for the hope that this atti- 

 tude of aloofness is a thing of the past, and indeed 

 lit is these stations that are contributing most to 

 jour knowledge of the phenomena of self-sterility of 

 fruit trees. 

 That the reproductive organs of fruit trees, like 

 ijthose of many other cultivated plants, are subject 

 'to grave disturbances is indicated by the fact that 

 not a few apples are very shy of pollen bearing. 

 Among varieties which exhibit this habit, Mr. 

 Hooper mentions Newtown Wonder, King of the 

 Pippins, Irish Peach, Baumann's Red Winter 

 Reinette, Cox's Pomona and Broad-eyed Pippin. 



Pears are apt even more than apples to be 

 >elf-sterile, and such varieties as William's Bon 

 iChretien, Pitmaston Duchess, Doyenn^ du 

 jComice, and others require to be planted in pro- 

 pinquity with good "pollenisers." Progressive 



^ "Notes on the Pollination of Orchards." By Cecil H. Hooper. The 

 Fruit, Fl<nverau(i Vegetable Trades' Journal, September, 191 5. 



NO. 2424, VOL. 97] 



fruit-growers are, of course, well aware of the 

 stubborn fact of partial or complete self-sterility, 

 and see to it that their orchards contain varieties 

 which supplement each other's pollen require- 

 ments ; but it is to be feared that many small 

 growers are not so alive to these facts as they 

 should be. However, so long as many of the 

 small orchards of this country are so ill-cultivated 

 as they are at present, self-sterility of varieties 

 is of no great moment to the trees or owners, 

 for 'the crops would inevitably be poor, in spite 

 of the introduction of good pollenisers. 



Of the insects visiting fruit trees and pre- 

 sumably engaged in transferring pollen to the 

 stigmas of the flowers, Mr. Hooper gives an in- 

 teresting list. In the case of apples observed 

 during 1912 and 1913, the record was : — Hive 

 bees, 72 ; bumble bees, 26 ; other wild bees, 2 ; 

 other insects, 20. The insect visitors to the 

 cherry were in somewhat similar proportions, but 

 in the case of the plum the visits of bumble 

 bees were to those of hive bees as 41 is to 29. 

 How far the reduction in numbers of hive bees 

 due to recent epidemics is likely to have an effect 

 on the yield of apples is an open question. 



Frederick Keeble. 



PROF. OCT A VE LIGNIER. 



PALEOBOTANY recently suffered a serious 

 loss in the death of Graf zu Solms-Laubach 

 and Prof. Zeiller. Another gap has been made in 

 the ranks of the small body of botanists whose 

 work is mainly concerned with extinct plants by 

 the death, on March 19, of Prof. Octave Lignier, 

 who occupied the chair of botany at Caen since 

 its foundation in 1889. Prof. Lignier w^as born 

 on February 25, 1855, ^^ Pougy (Aube, 

 Champagne). His earlier botanical studies 

 were chiefly concerned with investigations under- 

 taken to test the value of anatomical char- 

 acters as a guide to the affinities of the Caly- 

 canthaceae and other Dicotyledons. These re- 

 searches led him to adopt certain views with 

 regard to the important part played by the foliar 

 vascular system (the " meriphyte ") in the evolu- 

 tion of the conducting system of the stem. For 

 his original ideas on this subject Lignier did not 

 always receive his full share of credit. He also 

 wrote on the anatomy and floral morphology of 

 many other recent genera; but it is for his 

 numerous additions to our knowledge of Mesozoic 

 and Palaeozoic plants that he is best known. ^ One 

 of his most impKJrtant contributions is the mas- 

 terly account of Bennettites Morierei, a Cycadean 

 "flower," probably from the Gault. 



Among other important contributions by 

 Lignier reference may be made to his detailed 

 description of several sf)ecies of Jurassic and 

 Cretaceous Coniferous and Cycadean stems and 

 some Upper Cretaceous Angiospermous wood 

 referred to the Hamamelidaceae ; his ingenious 

 suggestions with regard to the relationships of 



1 For a list of Lignier'* papers, see "Titres et Travaux scienttfiques de 

 M. Octave Lignier." Laval, 1914. 



