38 
Tansley and Fritsch. 
Aegiceras majus (Myrsinaceae) also has viviparous embryos, 
which are, however, much smaller than those of the Rhizophoraceae. 
They are strongly curved, so that the lower very sharply pointed 
end points outwards or upwards when hanging on the tree. This 
species is not very common in Ceylon. It furnishes another 
excellent instance of the same adaption being evolved in two 
totally distinct families, owing to similarity of environment. 
Fig. 13. Shoot of Acanthus ilicifolius shewing mode of advance on the mud by 
means of stilt-roots. Half natural size. 
Lumnitzera rncemosa (Combretaceae) is another not uncommon 
tree of the mangrove-swamps of Ceylon. L. coccinea is very rare, 
having been reported only from the Bentotta river. According to 
Schimper it has knee-roots like Bruguiera. Scyphiphora hydro- 
phyllacea (Rubiacete), much like Lumnitzera in appearance, is also 
rare—reported from Jaffna only. These three trees form a sort of 
transition to the “semi-mangroves.” Their adaptations have been 
little investigated. 
At the conclusion of our description of the mangrove-vegetation 
we cannot omit to mention the characteristic covering of Algae, 
which is borne by the submerged parts of the roots of Rhizophora 
