Cross. — Observations on some Neiv Zealand Ilalophytes. 



563 



Cortex of thin- walled, hexagonal cells, some of which contain crystals. 

 On the ridges it is modified to form a thick-wall strengthening tissue of 

 small cells, and in the grooves 2-3 layers of chlorenchyma, recalUng the 

 structure of the cortex of Equisetum. 



The f.v. bundles are very anomalous in structure. According to 

 De Bary (i, p. 590-95), " There is first a primary ring of bundles, leaf 

 trace, and perhaps intercalary as well. While the development of these is 



still proceeding, round the 

 outer margins of their 

 phloems an extra fasci- 

 cular ring of cambium 

 appears, and forms on its 

 inner side alternately vas- 

 cular bundles and inter- 

 mediate tissue; on its 

 outer side, a thin layer 

 of bast parenchyma, or 

 nojio at all." The inter- 

 mediate tissue in sections 

 examined seems to have 

 formed a wide layer of 

 wood, wliich in L.S. ap- 

 pears to consist of tough, 

 fibrous elements. The 

 xylem of the small col- 

 lateral bundles can be 

 recognised among the in- 

 termediate tissue by its 

 thicker walls and larger 

 lumina. The phloem forms small groups interrupting the cambium ring, 

 while further out are groups of thick-walled cells (staining blue), perhaps 

 formed from a second ring of extrafascicular cambium. 



The pith is large, and consists of rounded, thin-walled cells, some with 

 crystals. 



8. Salicornia australis. 



Stem (Fig. 2, b). 



Epidermis : A single layer of cells with a sUghtly thickened cuticle. 

 The stomata are rather numerous, of medium size, narrow shtted, and not 

 sunk beneath the general surface, though Warming (v, p. 216) says they 

 have been so described. In surface-view the epidermal cells have a regular 

 polygonal outUne. 



PaUsade tissue 2-3 cells thick. In T.S. the cells are long, very narrow, 

 -closely packed, and contain numerous small rounded chromatophores. 



Water-bearing tissue occupies the greater part of the stem. The colls 

 are polygonal, thin-walled, contain no chromatophores, and have very 

 small intercellular spaces. Towards the outer Umits of this tissue there are 

 bundles of tracheides with spiral markings, forming a broken ring parallel 

 with the epidermis. According to De Bary (i) there are scattered tracheides 

 in Salicornia herhacea; but they occur in the chlorophyll tissue, and are 

 " perpendicular " to the epidermal cells. Warming (v, p. 215) mentions 

 similar tracheides in the green tissue of Salicornia herhacea. It is thought 

 by some authorities that these tracheides serve the purpose of air-storing 

 <xi, 357). 



Fig. 11. — Atreplex patula. 

 T.S. leaf, X 55. 



