THE FLOWERTXa-TTMES OF SOAIE BKTTTSH ELAIS 87 



understoofl tliat by "(lowering" I mean tlie opening of tlie ilower- 

 bvul just before the anthers dehisce : not tlie emission of the stigmas, 

 which cannot be seen except very close at hand. 



The trees observed by me belong certainly to two species and 

 include, I believe, some hybrids between them. These two species I 

 indicate hereafter, but, I fear, not very clearly. When dealing with 

 any species of Ulmus, I always feel myself on treacherous ground, 

 owing to the number of puzzling intermediate forms (due, without 

 doubt, to hj^bridisation) with which one meets. I am familiar, I 

 believe, with all the critical matter dealing with the genus which has 

 been published in England during the last ten years ; yet T have 

 a feeling that I know less of the matter now than I thought I knew 

 at the outset. The specific distinctions laid down by those who have 

 written on the subject seem to me highly confusing, and the decisions 

 they have arrived at often contradictory ; at all events, when I have 

 met with an unusual form in the field, I have generally found myself 

 unable to identify it beyond doubt with any described species or 

 variety. In the present case, I have had valuable assistance from 

 Prof. Augustine Henry, who has kindly examined and identified 

 flowers, fruit, and mature foliage from the trees in question. The 

 two species concerned may be defined as follows : — 



(1) The SiiooTH-LEAYED Elm (the "Common Essex Hedgerow 

 Elm," as I have been accustomed to call it), Uhnus nitens Moencli 

 {=JJ. glahra Miller, non Hudson ; j^f/e Moss, Cambr. Engl. Flora, 

 ii. 89 ; 1904) ; it is, how^ever, certainly the tree which most Essex 

 botanists have been accustomed to regard as U. campestris. It is 

 exceedingly abundant throughout the greater part of Essex, growing 

 usually in hedgerows and similar places ; very seldom in woods. Its 

 head is narrow (not rounded). It suckers very freely, especially 

 when young, and usually leafs very late in the year — often not until 

 nearly the 1st of June. In most years it produces an exceedingly 

 thin crop of fruit, its samaras being very small and usually infertile ; 

 yet in some j^ears, at long intervals, it produces an enormous crop, 

 and so exhausts its vegetative powers that it develops little or no 

 foliage until very late in the summer and is often affected similarly 

 in the following summer also. The last year in which this re- 

 markable phenomenon occurred was 1909, when it was observable 

 throughout the whole of Essex and in many adjoining counties. In 

 that year our Essex trees, almost without exception, indulged in a 

 perfect orgy of reproduction, and the croj^ of fruit they bore was 

 truly amazing in quantity — so much so that it attracted the atten- 

 tion of and surprised everyone who saw it : I published at the time 

 {JEissex Naturalist., xvi. 73-81 ; 1910) a full account of the pheno- 

 menon. One feature of it was that some of the seed produced on 

 this occasion was certainly fertile, though I had a suspicion that 

 this may have been borne by trees which were hybridized in some 

 degree Avith the next species, which habitually produces fertile 

 seed. 



The trees of this ;ipecies on which the following observations 



