March 11, 1904.] 



SCIENCE. 



415 



ancestral. It is now a well-established 

 generalization that palingenetie features of 

 anatomical structure are apt to persist in 

 reproductive axes, and consequently the oc- 

 currence of ligneous resin-canals in the 

 cones of certain species of Abies is good evi- 

 dence that resin-canals were once a general 

 feature of the wood in the ancestral species 

 of the genus. This conclusion is strongly 

 supported by the presence of resin-ducts in 

 the first annual ring only of vigorous 

 branches in certain species of the genus 

 under consideration, for in this instance we 

 have to do with the phenomenon of recapi- 

 tulation, so well exemplified in seedlings of 

 plants and in the young of animals. The 

 conclusion is accordingly drawn, from both 

 comparative anatomical and experimental 

 data, that the genus Abies has come from 

 ancestors possessing ligneous resin-ducts. 

 Similar data in the case of the other genera 

 usually described as lacking ligneoiis resin- 

 canals, viz., Cedrus, Pseudolarix and Tsuga, 

 lead to the same conclusion, that is, that 

 these too have, come from ancestry posses- 

 sing ligneous resin-canals. As a further 

 consequence of these observations the gen- 

 eralization is made that the older type of 

 wood in the Abietinege, is that in which 

 resin-canals are present. The full signifi- 

 cance of this generalization does not appear 

 at the present time, but will be made clear 

 as the remaining families of the Coniferales 

 are described, from both the morphological 

 and the anatomical standpoints. 



Vegetative Reproduction in Certain Epi- 

 phyllous Lejeunece: Professor A. W. 

 Evans, Yale University. 

 The circular or oblong discoid gemmse 

 found in Lejeunea convexistipa, L. accedens 

 and an allied new species were described. 

 Each consists of a single layer of cells and 

 is attached by its margin to a single pro- 

 jecting leaf-cell. Similar gemmae have 

 been described for the genus Radula and 



also for other LejeuncEe, but all of these 

 differ in various points of detail. In the 

 two Lejeunea referred to the gemmse are 

 shaped like a watch-glass and become in- 

 verted before germination takes place, in 

 this way turning their concave faces toward 

 the substratum. In the flat gemma of the 

 undescribed species no such inversion seems 

 to be necessary. In L. convexistipa the 

 gemma retains its apical cell and upon ger- 

 mination gives rise directly to a leafy shoot. 

 In L. accedens the gemma does not retain 

 its apical cell and upon germination pro- 

 duces a flat protonema, from which the leafy 

 shoot develops later. In the undescribed 

 species both types of germination occur. 

 This last plant is further remarkable be- 

 cause the protonema sometimes gives rise 

 to secondary gemmce, similar in all respects 

 to those developed on the leaves. In this 

 respect it resembles the peculiar genus 

 Metzgeriopsis, of Java, in which the long- 

 lived protonema bears both discoid gemmas 

 and leafy shoots. 



Additional Notes on the Structure of the 

 Starch Grain: Dr. Henry Kraemer, 

 Philadelphia College of Pharmacy. 

 The author has continued his work on 

 the study of the starch grain, and presented 

 evidence to show (1) That the peripherical 

 layer of the starch grain is a distinct mem- 

 brane; (2) that soluble starch is present in 

 the unaltered grain ; ( 3 ) that iodine forms 

 a definite, but easily dissociated, compound 

 with starch; and (4) he gave a method for 

 staining wheat starch grains. This method 

 is as follows: To 0.500 gm. of starch add 

 2 c.c. of an aqueous iodine solution (con- 

 taining 0.1 per cent, of iodine and 0.5 per 

 cent, of potassium iodide) ; allow the mix- 

 ture to stand 20 minutes, and then add 2 c.c. 

 of a saturated aqueous solution of gentian 

 violet; allow this mixture to stand from 

 12 to 24 hours, examining mounts of the 

 material from time to time ; when the grains 



