636 



SCIENCE 



[N. S. Vol. XXXI. No. 799 



A New Method of Detecting Traces of Illuminating 

 Gas: Lee I. Knight, R. Catlin Rose and 

 WiLUAM Ceockee. 



It has been shown that 12.5 parts of illumina- 

 ting gas or .5 part of ethylene per million of air 

 will play havoc with flowers of the carnation. 

 Chemical tests will detect no less than 100 parts 

 of illuminating gas per million of air. In a num- 

 ber of cases known to us greenhouse men have 

 been unable to determine, through lack of a deli- 

 cate test, whether illuminating gas was the cause 

 of serious injuries to their crop. In these cases 

 there was much evidence that gas leaking from 

 imperfect pipes, seeping through the ground up 

 into greenhouses was the cause of the injury. 

 The injuries occurred in cold weather when the 

 ground was frozen and the houses could be little 

 aerated and they ceased with the repair or re- 

 moval of the defective pipes. We believe from 

 our results reported in the paper above that the 

 etiolated epicotyl of the sweet pea will furnish a 

 delicate and accurate test for traces of illumina- 

 ting gas. 



The Stele of Osmunda oinnamomea: J. H. Faull. 



Nodal rays occur in the xylem of seedlings of 

 Osmunda oinnamomea, and eventually the edges of 

 one of them close around the intruding paren- 

 chyma to form a " stelar " pith. The " extra- 

 stelar " pith arises as an eccentric pocket at the 

 inner entrance to a leaf-gap. Its connection with 

 the cortex has been observed in the adult only. 

 Branching is not a seedling character. The seed- 

 ling stage is long drawn out, and variable. In- 

 ternal phloem has been found in abnormal un- 

 branched plants. 



There is a marked tendency in the Osmundaceae 

 for the xylem to encroach on the pith. Thus in 

 Osmunda dnnamomea one finds internal strands 

 of xylem, closure of the inner ends of medullary 



rays (in reduced plants to the extent of simu- 

 lating the cladosiphony of Osmundites Dunlopi, 

 etc. ) , parenchyma pockets in the xylem ( charac- 

 teristic of the family), projections of the internal 

 endodermis in these pockets, etc., all of which 

 indicate a tendency towards " cladosiphony " in. 

 the Osmundaceae, and a possible point of contact 

 with the Gleioheniaceae. 



The facts connected with the stele of 0. oin- 

 namomea are held to support the theory of the 

 reduction of the osmundaceous stele from an 

 amphiphloic siphonostele. 

 The Ontogeny of Helvella elastica: W. A. Mc- 



Cdbbin. 



The fruiting body arises from aggregated masses 

 of the mycelium. It is enclosed at first by .a 

 definite velum which early degenerates. Through- 

 out life a layer of club-shaped palisade hyphse 

 covers the whole surface. Scattered throughout 

 all parts of the interior except in the stem, are 

 large irregular cells serving apparently as storage 

 organs. 



The ascogenous hyphse are diflterentiated from 

 ordinary hyphal filaments and form a subhy- 

 menial layer. These ascogenous hyphae produce 

 lateral branches from whose 2-nucleate, terminal 

 cells the usual 4-nucleate hooks are formed. 



The process from the antepenultimate cell of 

 this hook may, without fusion of its two nuclei, 

 form a second and similar hook, and this series 

 may extend to at least a sixth, the process from 

 the last, after nuclear fusion, becoming the ascua. 

 Thus the two nuclei imiting to form the primary 

 ascus nucleus are separately descended from the 

 two in the terminal cell of the ascogenous hypha. 



In any hook of a series the terminal and. ante- 

 penultimate cells may fuse, their nuclei passing 

 into a process arising from the terminal cell. This 

 process is equivalent to that arising from the 

 penultimate cell and becomes likewise either an 

 ascus or another hook. 

 An Unusual Walnut: Iea D. Cardiff. 



Two instances of peculiar walnuts have come 

 to the attention of the author: one from a tree 

 of northern Indiana and the other from a tree of 

 southern Tennessee. The trees were found to be 

 walnut {Juglans nigra) in essentially all but 

 their nut characters. The nut itself, externally 

 at least, is very different in appearance from a 

 walnut. The basal portion resembles very closely 

 a walnut while the apical portion resembles a 

 hickory nut, showing the four furrows that divide 

 the external shell into its four valves. These fur- 

 rows, however, do not extend entirely through the 



