1 88 Gibbs. — Bio-histological notes on some new 
or by an extreme leaf development, or the specialization of vegetative shoots 
which succeed the earlier flowering ones. These secondary vegetative shoots, 
as well as many herbaceous and other plants with soft woody stems, show a 
decumbent tendency, ultimately spreading on the ground. Striking organo- 
graphical deviations to meet physiological conditions are conspicuous by 
their absence, and this fact is no doubt due to the sufficiency of underground 
moisture which can be drawn upon as required. The limitation of that 
supply, however, is shown by the strict economy exercised in its distribution. 
The characteristic spacing of trees, already referred to 1 , is reproduced in the 
growth of herbaceous plants, and may probably be referred to this factor. 
Each plant whilst exhausting the water supply in its own vicinity tends to 
crowd out other competitors by extending its shade area, and thus exercises, 
possibly as a secondary result, a retarding influence on evaporation. 
This bare sufficiency of soil moisture is apparent in the general begin- 
ning of plant life in September and October, before the rains. The rigid 
economy necessitated by the limit of that supply is seen in the tendency of 
trees and shrubs to flower before the leaves expand, and this habit is further 
modified in herbaceous plants by the development of specialized flowering 
shoots. In this way the whole energy of the plants is centred on vegetative 
activity only during the short season favourable to growth. 
The bulbous annual tender herbaceous plants are apparently restricted 
to the summer or rainy season. The few species of Crinum , Buphane , Albnca , 
Urginea and Gladiolus which signal the early spring invariably send up the 
flowering scapes first, even the fruit maturing before the leaves appear ; 
but in the case of bulbs of Albuca caudata Jacq. and corms of Gladiolus 
Melleri 2 brought back by Baker this habit has proved to be due to bio- 
logical conditions. Under favourable cultivation both flowering scape and 
leaves have been simultaneously developed. The same remarks apply to 
trees and shrubs found growing under varying conditions in their natural 
surroundings . 3 The Fuirena and Justicia species here described would thus 
prove exceptional to the general rule, being characterized by very distinct 
organographical modification which takes the form of starch storage tissue, 
in the former a portion of the stem, and in the latter special leaves, being 
involved in its elaboration. In both examples, however, this specialization is 
not to meet the long physiological drought conditions of widely different 
edaphic character ( Fuirena Oedipus being a hygrophilous and Justicia 
elegantula a veld-type) to which each plant is exposed, but to ensure suffi- 
cient reserve food supplies to promote a rapid spring growth, with the least 
expenditure of energy. 
1 Gibbs, 1. c. 
2 This case is particularly interesting, as the corms were given to Dr. Bolus at Cape Town and 
grown out of doors. The first time the plant flowered, the foliage did not come up till two 
months later, but the second year both scape and leaves came up together. 
3 Gibbs, 1. c. 
