8 o 
L. Cockayne. 
numerous and form a rather dense, springy, interlacing mass. The 
terete spines are arranged decussately at distances of about 2cm. 
and measure 2cm. to 3cm. in length and 1mm. to l*5mm. in diameter. 
Except at the actual pungent apices, they are bright green when 
young, as are also the flexible axes of the ultimate shoots, but 
finally they dry up, becoming brown and very hard, thus furnishing 
a most formidable protection against intruders. The small leaves, 
-5-1 • 1 cm X 5cm. from the axils of which the spines aregiven off, are 
not very numerous at any time, and in the winter are quite wanting. 
In the spring the leaves are at a maximum 1 and occur for the most 
part on much reduced flowering shoots, given off just below the 
spines. Here too, ordinary long shoots arise; at first, owing to 
their spines not being nearly fully developed, they much resemble 
juvenile shoots, and these add to the leaf-area. But it is only 
during the above season that the leaves play any part worth 
considering in photosynthesis; at other times, it is only the spines 
and shoot-axes that are of moment in this regard. 
The early seedling form is quite without spines, being an erect 
leafy plant. After attaining a height of several centimetres, varying 
probably considerably according to environment, spines commence 
to be developed from the axils of the leaves as in the adult, and the 
plant thenceforth becomes by degrees comparatively leafless and 
very spinous. The juvenile leaves are very similar to those of the 
adult, but are thinner and the earliest leaves are toothed. 2 
Two such seedlings artificially raised from seed in a green¬ 
house, after developing one or two spines, were placed by me more 
than three years ago in a glass case, so constructed as to keep the 
inside atmosphere constantly saturated with moisture, in order 
to see if the plants would continue to produce spines; i.e. if this 
artificial environment would inhibit the formation of spines. The 
conditions provided would not only expose the plants to moist air, 
but the light would be considerably more feeble than that of the 
normal stations of the Discaria. Such conditions indeed would 
be those of a rain-forest interior rather than of a plain or hillside in 
the open, however wet the climate. 
After the plants had been in the moist chamber for one year, 1 
took the photograph here reproduced, (Plate II., Fig. 1) fixing for 
1 The figure in Kirk’s Forest Flora, loc. cit. shows this state of 
the plant. 
2 L. Cockayne. An inquiry into the Seedling Forms of New 
Zealand Phanerogams and their Development. Trans. N.Z. 
Inst., Vol. XXXII., 1900, pp. 92-94. 
