tissue is composed of granular phloem parenchyma (fig. 3c, p. par.), whose cells appear roundish in transverse section, and a few sieve-tubes with transverse plates (fig. 3c, s. t.). There is a well-developed cambium of 4–5 layers of small, squarish, transversely elongated cells containing conspicuous nuclei.

The xylem forms more than half the thickness of the entire vascular bundle. There are but few true vessels, one or two spiral and one or two pitted, in each bundle; the greater part of the xylem tissue is composed of libriform cells. In transverse section these appear as polygonal cells with very thick walls, and fitting closely into each other. In a longitudinal radial section (fig. 3c) they are seen to consist of greatly elongated cells, with oblique end walls which dovetail into each other. The thickened cell-walls have thin spots both on longitudinal and transverse walls by which they can communicate with each other. The true vessels occur in the inner part of the vascular xylem.

The pith-cells, which occupy the centre of the stem, are smaller on the outside (next to the xylem) and larger in the centre of the stem. They are polygonal, thin-walled, about as long as they are broad; those next to the xylem contain a great many starch-grains (in winter), while those in the centre have only a few starch-grains.

The older stems and spines become dry and scaly; only the younger can assimilate. The most remarkable features about the structure of the stem are the double epidermis, the great development of chlorenchyma and of woody cells, and at the same time the small number of true vessels in the wood. The two former are evidently intimately concerned with the work of assimilation, and the latter with the question of rigidity. The abundant palisade chlorenchyma facilitates assimilation, while the libriform cells give the stem the rigidity and at the same time the elasticity so necessary to a plant which is often exposed to wind.

Clematis afoliata, Buchanan.

Hooker does not mention this species in the “Handbook of New Zealand Flora,” but T. Kirk, in the “Students' Flora of New Zealand,” mentions it on p. 3. He says its habitat is “Middle Island: Nelson, Marlborough, Canterbury, and Otago; but local.” It belongs to the order Ranunculaceœ. In other species of the same genus the leaves have a long petiole; in this species only the petiole is present—at least; in the adult plant. The petioles arise in pairs from a node, each pair being at right angles to the pair above it; the internodes are very long (about 7 in. in older shoots). The young shoot arises in the axil of the petiole, with the inflorescence at its

This genus belongs to the order Leguminosœ. Hooker^* says, “This genus is confined to New Zealand, and is composed of shrubs or small trees, usually quite leafless, or leafy in the young state only. The branches are flattened and green.” Diels^† Hab. North and South Islands: East Coast, Milford Sound, Nelson, Otago, Akaroa.says concerning this genus, “Carmichaelia exsul, with many tender leaves, grows in the underwood of the palm forests of Lord Howe Island; and even Carmïchaelia australis, the only representative of its stock in the northwest of New Zealand, still parades in a rich foliage…. In their growth they certainly all bear pinnate leaves, like the phyllode-bearing Acacias of New Zealand. These leaves, in the neighbourhood of the soil protected by the shade of higher growths and by a hairy covering from drying up, possess anthocyanin in their interior and insunk stomata. From the beginning stem and leaf-stalk are provided with chlorenchyma and stereom, so that when they have attained a height of 5 cm. the little plants already stop leaf-formation and transfer the function of the leaves to flat shoots which now serve for nourishment for several years.” I had no opportunity of examining young plants. All three species agree in the flattened arrangement of their shoots, but differ somewhat in habit.

Carmichaelia flagelliformis, Colenso.^‡

[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]

This is a shrub about 2 ft.—4 ft. in height, much branched with rather slender branchlets (fig. 6a); often it straggles on the ground. A few very small leaves appear on the young branches (not on the older ones), with the inflorescences; these are only 1/10 in. in length (October), and hence are not of much practical use as assimilatory organs (fig. 6b). The leaves are of the ordinary dorsiventral type; they have a few hairs on their upper and lower surfaces, the stomata are borne on the lower surface, and there is a violet colouration (anthocyanin) in some of the subepidermal cells of the lower surface. The shoots arise at an acute angle from the branch which bears them, and their flattened surfaces are not horizontal, but vertical; so the sun's rays do not strike them directly, evaporation being lessened by this means. A similar growth of shoot-axes is seen also in Carmichaelia monroi (fig. 8) and C. nana (not represented).

[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]

The flattened shoot of C. flagelliformis is about 1/12 in. broad; in C. monroi it is about ⅙ in. broad, and is slightly stouter; in C. nana it is very slender, the flattened surface being about ⅛ in. broad.

Stem-structure.—On the outside is a double-layered epidermis, with slightly insunk stomata. There is a thick cuticle outside. The cells of the outer epidermal layer are larger than those of the inner layer, and are somewhat different in shape, those of the outer layer being squarish, while those of the inner layer are somewhat elongated in a direction at right angles to the radial one (fig. 7a). The lower epidermal layer is wanting immediately under the stomata.

Immediately below the epidermis is a ring of chlorenchyma tissue extending right round the stem. This ring is not complete, but is interrupted by the strands of mechanical tissue, which occur in large numbers immediately below the epidermis. So the chlorenchyma and stereom alternate round the stem. Each of the stereom groups is small, and does not extend inwards as far as the vascular bundles. The cells are small, thick-walled, elongated, polygonal in transverse section (fig. 7a, m. st.). Each group is surrounded (except on the side which is adjacent to the epidermis) by a layer of thin-walled colourless polygonal cells which separate the mechanical tissue from the chlorenchyma. Small groups of stereom cells, surrounded by a layer of thin-walled cells, also occur in the chlorenchyma; these groups alternate with the subepidermal ones. There are also a few stereom cells on the outside and inside of each vascular bundle, but in this case there is no layer of thin-walled cells accompanying them. The chlorenchyma cells are larger than those of the stereom tissue. They extend inwards as far as the ring of vascular bundles. The stomata occur only above the chlorophyll tissue in the epidermis. The outer chlorophyll - containing cells are elongated in the radial direction, and have the form of palisade tissue; further inwards they are more irregular in shape, with fewer granules and air-spaces between them.

The vascular bundles are arranged in an oblong ring round the central pith, with medullary rays between them. They are composed of phloem, cambium, and xylem. As the stem grows older, thickening takes place; the originally flat organ is rounded off, so the assimilatory tissue is not interfered with. A great part of the xylem thickening consists of libriform cells (fig. 7c, l. t.); these are able to support the stem, so the stereom tissue becomes less necessary.

The cells of the pith are large and polygonal; those of the medullary rays are elongated radially to a slight extent.

Anthocyanin is developed in the epidermal tissue of the edges of the shoot, but not of the flattened sides; probably this may be explained by the fact that owing to the habit of the plant only the edges receive the sun's rays directly.

C. monroi, Hooker,^* and C. nana, Colenso.† Hab. North Island: Dry mountainous country at base of Mount Tongariro. South Island: Southern Alps; Otago, Waitaki River.

Both of these differ in habit from C. flagelliformis. Their growth resembles that of alpine plants. C. nana is a “very dwarfy, glabrous, rigid shrub, 2 in.–4 in. high, with much-compressed minutely striated branchlets ½ in. — ⅛ in. in diameter” (Hooker). C. monroi grows higher, reaching about 1ft. in height, but much more closely, forming a very firm cushion of circular form, in which, however, the individual branches and branchlets are easily separated and distinguished. In neither is there any sign of leaves in the adult form, and they flower later than Carmichaelia flagelliformis. The tips of the shoots in C. monroi are coloured brownish-red.

Stem-structure.—In general stem-structure they resemble C. flagelliformis, but the chlorophyll tissue is developed in greater abundance in proportion to the stereom tissue than in the latter. There is the same double-layered epidermis with thick external cuticle; in C. monroi there are slight ridges above the stereom strands, while the stomata occur in the depressions, underneath which is the chlorophyll tissue. Underneath each stoma is an air-cavity. The chlorenchyma tissue extends inwards as far as the vascular bundles, and is of palisade type in both C. monroi and C. nana, without any air-spaces even in the inner layers. (Compare C. flagelliformis, where air-spaces are present.)

In C. monroi the stereom tissue may or may not extend inwards as far as the vascular bundle (fig. 9); when it does not there are occasional small isolated groups alternating with the peripheral groups, and occurring in the chlorophyll tissue. Both these groups have a layer of polygonal thin-walled cells around them. Where the stereom tissue does not extend as far as the vascular bundle there is a crescent-shaped group of stereom cells on the outside of the phloem, with a half-circle of thin-walled cells round the outside; there are also a few similar thick-walled cells on the inside of the xylem, but with no special thin-walled cells round them. The pith is composed of large polygonal cells fitting together, without intercellular spaces. The medullary-ray cells are similar in shape, but somewhat smaller; they pass over gradually into the chlorenchyma cells. The stereom cells are polygonal, tightly packed together; when the shoot is quite young, as also in C. flagelliformis, the cell-walls are quite thin, and the stem is then very soft; but it soon loses its softness and becomes firm owing to the thickening of the cell-walls.

In C. nana the stem is much thinner. There are not so many vascular bundles as in the stem of C. monroi, nor are they opposite each other. The stereom strands reach to the vascular bundle, surrounded on outside by the thin-walled polygonal layer of cells seen also in C. monroi and C. flagelli-formis. The cuticle is not quite so thick as in C. monroi; the stomata occur in a similar place (above chlorenchyma in the epidermis). The chlorenchyma is palisade, but there are occasional air-cavities (fig. 10b). A few isolated groups of thick-walled cells, with a surrounding ring of thin-walled cells, occur in the chlorenchyma tissue, but these are of minor importance owing to their small size. On the inside of the xylem occurs a group of stereom cells; there may be only a few (as in vascular bundle on right hand of fig. 10b), or more (as in vascular bundle on left-hand side of the same figure). The pith-cells are large and polygonal. Since the tissues composing the stems of the three species are similar, a longitudinal section of the stem of C. nana only is given (fig. 10b). The stereom cells are seen to be somewhat elongated with oblique transverse walls, all the walls being much thickened. (The thin-walled layer of cells is not represented.) The phloem elements include sieve-tubes and phloem parenchyma (fig. 10b, s. t., p. par.), with cambium (cm.) on inside. Xylem elements include spiral vessels (sp. v.), pitted vessels (p. v.), with elongated woody cells between. Inside of the xylem is the stereom tissue, followed by the pith, and on the other side chlorenchyma with epidermis. The opening of the stoma is seen best in longitudinal section. The stomata of all three species are fairly numerous, not very large, with no peculiar structure, and only very little insunk (figs. 10b and 7b).

At the apex of the shoot of C. monroi, a violet-coloured fluid (anthocyanin) is present in the inner epidermal cells; lower down in the stem it is absent; it is also absent in C. nana.

The stems of all three species are glabrous.

In the five species which have been considered, evidently the chief danger to be guarded against is excessive transpiration. The total absence of hairs (except in the minute leaf of C. flagelliformis) so commonly occurring in alpine plants shows that it is not a question of loss of heat, but rather of avoidance of excessive heat. This is effected in the case of the Carmichaelias by the vertical position of the shoot-axis, and probably in C. monroi by the development of anthocyanin in the shoot-apices (the lower parts being protected by the cushion-like form of the plant). Transpiration is checked chiefly by the thick cuticle found in all of them, and