137 
Species of the New Zealand Orchidaceae. 
tracheides have their pits arranged in regular order a little distance apart ; 
in the larger the pits are more elongated, but closer together. Cuticle 
occurs on both surfaces, but is thicker on the upper. The cells adjoining 
the upper epidermis are somewhat elongated in transverse section, and in 
tangential section they resemble palisade structure to a certain extent. Below 
this row they contain numerous chlorophyll granules. In the assimila- 
tory tissue of the lower portion of the leaf the cells are connected together 
by short tubular extensions, across each of which is a pitted diaphragm. 
Large intercellular spaces occur in this region. Isolated elements, elongated 
in tangential section and containing raphides, are to be found between the 
vascular bundles lying towards the edge of the leaf. Stomata occur on the 
lower surface. Their walls are extremely thick, and the outer are covered 
by the cuticle. Above the midrib the cells are large and thin-walled ; their 
protoplasm is vacuolated, and they contain few chlorophyll granules. 
Earina suaveolens , Lindl. Bot. Reg. (1843) Misc. 61. 
Stems stout, erect or pendulous, slightly compressed, 6-18 in. high. 
Branches numerous, close-set. Leaves 2-4 in. long, | in. broad, narrow 
linear, acute, rigid, coriaceous, striate, midrib evident. Panicle terminal, 
2-4 in. long, many-flowered. Flowers sessile, much closer together than 
in E . mucronata , | in. in diameter, waxy-white with a yellow centre ; 
very fragrant. 
The root does not usually branch. Its velamen consists of from three 
to five rows of cells, of which only the inner have cutinized walls (PL VIII, 
Fig. 28). The thickening strands on all the walls are more or less radial. 
The innermost cells are elongated in both tangential and longitudinal 
directions ; fewer strands are present on their walls than on those of the 
outer rows. In the exodermis only the outer and the radial walls are 
cutinized. Three or four thickened cells occur between any two passage 
cells. Adjoining the latter on the inner side are the usual two small cortical 
cells containing numerous chlorophyll granules. Reticulately pitted cells 
are present in the outer and in the innermost rows of cortex, especially in 
the latter. The larger cells in the middle region have spiral bands or pits 
of various sizes in their walls. Chlorophyll occurs throughout, but it 
is denser near the inner and outer limits. Cells containing raphides lie 
near the exodermis. The walls of the thickened cells of the endodermis are 
cutinized and striated, while those of the passage and of the one or two adjoin- 
ingpericycle cells are of cellulose. Twelve groups of xylem and phloem are 
usually present. As in E. mucronata , the former consist of small tracheides 
and spiral vessels, and the latter of sieve-tubes and companion cells. 
Sclerenchymatous fibres lie between the groups, but near the centre of the 
cylinder they give place to large cellulose-walled elements containing a 
little chlorophyll. 
