AIZOACEAE 205 



Plate 51. 



Mesembrianthemum. 



A. M. aurantiacum Haw. 1. Small piece of plant. 2. Transverse section through 

 petal. 250/1. 



B. M. Hookeri Berger, from Windsorton. 1. Patch of plants in their natural 

 locality. 2. Single plant with ripe capsule. 3. Long, section of flowering twig 

 (corpusculum), with bud of young corpusculum. 



C. M. mitratum Marl. (Trans. Roy. Soc. S. A., Vol. 1, 1910), from Little 

 Namaqualand. 



D. M. Bolusii Hook. fil. Plant in its natural locality, showing six leaves. 

 2. Youns; plant, the flat body formed by the enlarged cotyledons; in the centre the first 

 pair of leaves. 



Mesembrianthemum mitratum. This plant has a remarkable habit of growth, 

 forming shrublets 1 — 2 feet high, the branches being apparently dead, but 

 each one carrying a fleshy knob at its end. The knob really consists of two 

 closely joined leaves, which include a bud. In spring the flower forces its way 

 out through a slit at the side, and while the fruit is ripening, a new bud, of 

 two similar leaves, forms alongside of it, absorbing the food material of the 

 older leaves and then remaining dormant until the next season. 



The plant was discovered by Mr G. Alston in the sandy desert belt 

 near Port Nolloth. 



Mesembrianthemum aurantiacum. A small trailing shrublet, but by its 

 flowers one of the brightest species, occurring in several shades, from bright 

 orange to deep magenta or maroon. The name Mesembrianthemum means 

 midday flower, but there is a great diversity in the hour of the day or night at 

 which the flowers open. Most species show their flowers in bright sunlight 

 only, but others do so at night, like the fragrant M. noctiflorum, or towards 

 evening like M. Bolusii, M. tigrinum and others of the section Ringentia. Most 

 species close their flowers during dull weather and re-open them the next day 

 in sunshine ; but some do not close them at all, when once open, not even in 

 rain, like M. falcatum. Some, like those of the latter species, last for 10 or 

 more days, while others wither after a few hours flowering. 



Mesembrianthemum Hookeri*. This species of the section Sphaeroidea was 

 figured by Hooker (Bot. Mag. Tab. 6077) as M. truncatellum\ ; but it is 

 evidently different from Haworth's original plant, hence its new name. It 

 is one of the few plants with window leaves, being embedded in the soil and 

 showing only the flat apex of the corpusculum. While the subterranean 

 portion is delicately green, the apex is marked exactly like the ferrugineous 

 soil and the pebbles surrounding it, thus providing one of the best illustrations 

 of protective mimicry among plants. 



We have sometimes searched for hours at localities where the plant was 

 known to grow, without discovering it, so well does it harmonize with the 

 surface of the ground. Our figure is only a modest attempt to represent the 

 conditions as they exist in nature. 



* See note on next page. 



+ The real M. truncatellum is not known at present. 



