42 SCIENCE PROGRESS 



very useful reminder of the state of our knowledge on this point. 

 Exclusive of a number of instances amongst Grasses and 

 Sedges, the phenomenon has been observed in some twenty- 

 four genera, and in addition to the examples already known the 

 author records an intrafascicular cambium in the axes of Ere- 

 murus himalaicus, Nothoscordum fragrans, and Asparagus 

 officinalis. This brings up the number of Liliaceous genera 

 exhibiting the feature to fourteen, and the other families in 

 which it occurs include the Orchidacese, Palmae, Junca- 

 ginaceae, Zingiberacese, Typhaceae, Musaceae and Comme- 

 linaceae, besides the Gramineae and Cyperaceae already referred 

 to. 



Evidently then the potentiality for secondary thickening 

 was very widespread and probably future research will reveal 

 its occurrence in the remaining three Cohorts in which so far a 

 cambium has not been observed. 



The number of investigated gametophytes of Lycopodium 

 is so small that any addition to our knowledge is welcome. 

 Chamberlain has recently described those of Lycopodium laterale, 

 L. scoriosum, and L. volubile (Bot. Gaz., Jan. 191 7). In the 

 first of these species the prothallus is green and leafy and 

 possesses a protocorm closely resembling that of L. cernuum. 

 In the two latter the prothallus is subterranean, and there is no 

 protocorm present. 



The adult sporophyte of L. volubile is Selaginella-like in 

 habit and, in common with L. scoriosum, possesses a dorsiventral 

 stele with the xylem in horizontal plates. It is therefore of 

 interest that in both these species the stele of the young 

 sporophyte shows a radial construction with apparently centri- 

 petal development. 



Genetics. — Bateson in the Journal of Genetics (Dec. 19 16) 

 has described an interesting case of bud variation. He finds 

 that the root shoots of the double white Bouvardia known as 

 " Bridesmaid " produce flowers which are pink and in every 

 respect correspond to the kind known as " Hogarth." Since 

 the root cuttings arise endogenously he suggests that Brides- 

 maid is a periclinial chimaera in which the epidermis and 

 hypodermis belong to the white form and consequently offspring 

 raised from seed are of the Bridesmaid type. Since the original 

 parent was doubtless raised from seed its peculiar organisation, 

 assuming that Bateson's explanation be correct, can only be 



