﻿1903] 



BRIEFER ARTICLES 



^IS 



The so-called conducting tissue of the style consists of cells elon- 

 gated in the direction of the long axis of the ovary, and differs in no 

 material respect from that ordinarily seen. The pollen tube passes 

 down the axial tissue of the style till near the cavity of the ovary, 

 where it turns and passes down the ovary wall close to the mar- 

 gin of the cavity. The tissue through which it 

 passes after leaving the style has nothing by 

 which it could be designated "conducting tis- 

 sue," but consists of nearly isodiametric cells. 

 When a point is reached a little below the 

 funiculus, the pollen tube curves, passes through 

 a region of deeply-stained cells (as though 

 mucilaginous), and when under the ovule turns 

 upward towards the embryo sac. 



While the course of the tube is not difficult 

 to see in the ovary wall, it is particularly con- 

 spicuous as it passes through the parenchyma- 

 tous cells of the chalaza and nucellus. The 

 account of the course taken by the pollen 

 tube, as described above, is essentially that 



J 



The branch- 



ing of the tube recorded by Nawaschin ap- Diagram illustrating 

 pears to have its counterpart in the pecan, chalazogamy in the pecan: 

 Although I have not settled this point by a A placenta, cut in the 



nuri^a^^r- ^t ^-u ^' ^Tj'j j-..'^ plane of fusion with the 



number or observations, yet I did see a distinct ^ „ , 



, -^ ovary wall; the approxi- 



branching in one case, and nearly every ovule ^^^^ j-^^^ ^f j^,;^^ ^,^ 

 examined showed the presence of more than represented by dotted Hnes; 

 one tube in the nucellus. If branching occurs, /fibrovascular bundles run- 

 it takes place after the pollen tube has entered ^^^^^^ the ovule; «,nucel- 



tViia 01, Kf.,*.' 1 i.- * lus; w, micropylar canal; 



tne suDtunicular tissue. 



Nothing definite has been made out as to 



//, pollen tube. 



the process of fertilization, or the nature of the embryo sac, but it is 

 hoped that additional material will reveal something of interest along 

 these lines. — Frederick H. Billings, Louisiana State University. 



SELECTED NOTES. 



Leaf variation in Liriodendron Tulipifera,—K recent article by 

 E, M. Berry on the phylogeny of Liriodendron (Box. Gaz. 34:44-63- 

 1902) attracted my attention to the subject of leaf variation in this 



