272 Winton — Anatomy of the Fruit of Cocos nucifera. 



silicified cells and did not understand that they are sclerenchy- 

 matized cells with silicious contents. Yon Hoehnel,* who 

 uses, however, the term " stegmata," also appears to have 

 fallen into the same error. 



Rosanoft'f found stegmata in twelve species of palms, and 

 Kohy who has made an exhaustive study of the subject, in 

 twenty-three additional species. Neither author mentions 

 Cocos nucifera, but Kohl found in C. flexuosa stegamata 

 with silicious contents which answer the description of those 

 in coir fiber. 



{3. Bast-fibers (figs. 5 and 6, f) completely surround the 

 bundle. They vary in length up to 2 mm and in diameter up to 

 •03 mm . The double cell walls are from one-half to one-sixth 

 the breadth of the lumina, with conspicuous pores and diag- 

 onal markings. In longitudinal section the walls adjoining the 

 stegmata are sinuous in outline, due to the depressions into 

 which the stegmata are fitted. On the edge of the xylem the 

 bast-fibers pass into tracheids (fig. 6, t). 



7. Xylem (fig. 5, x ; fig. 6). The elements are tracheae, 

 tracheids and various forms intermediate between tracheids 

 and bast -fibers, and tracheids and parenchyma. 



The tracheae range in diameter up to *05 ram , the larger 

 (found in large fibers) being reticulated (fig. 6, r) or scalari- 

 form-reticulated (sc), the smaller (found both in large and 

 small fibers) being spiral or reticulated spiral. Among the 

 spiral tracheae one finds considerable variation both as to their 

 size and the steepness of their spirals. As might be expected, 

 those in the protoxylem often have delicate spirals with turns 

 wide apart. An intermediate form is shown in fig. 6 (sp). 



The tracheids, distinguished from the tracheae by the trans- 

 verse or diagonal partitions and by their smaller size and thin- 

 ner walls, likewise display an interesting diversity of size and 

 form. Among these are forms with large pits and curious 

 reticulations (fig. 6, f), also transitional forms between tracheids 

 and bast-fibers (t) on the one hand, and tracheids and paren- 

 chyma on the other. 



8 Phloem. Sieve tubes and cambiform cells make up the 

 phloem (fig. 5,pk). 



Measured in cross sections, the diameters of the sieve tubes 

 vary up to *03 mm . In longitudinal sections it may be seen that 

 the sieve plates are either at right angles to the walls or oblique 

 and that oftentimes they are covered with callus through 

 which run a few indistinct pores (fig. 6, s). 



* Loc. cit, p. 52. 



•f Bot. Ztg., 1871, p. 749. 



I Kalksalze und Kieselsaure in der Pflanze, Marburg, 1889, p. 289. 



