72 
We now turn to Schimper's " Plant Geography on a physiological basis," Fisher's 
English translation (Groom and Balfour), 1903. At p. 73 we have- 
In many cases certain lateral roots are differentiated as oxygen-pumps, and in accordance with this 
function differ structurally from other roots. Such respiratory roots or piwumatophores (Jost) have been 
studied by Schenck in species of Jussieuea inhabiting in numbers, as shrubs or ur.dershrubs, the shallow 
waters of warmer districts. 
At fig. 47 are shown the pneumatophores of J, peruviana L. Inconspicuous 
pncumatophores (spongy bodies) may be seen in the common J. repens L. about Sydney. 
Then we may turn to the section " The Eastern Mangrove " at p. 395, the term 
Mangrove having more than a generic significance, including species of various families, 
but having a common habitat. 
On the other har,d, the roots of most Mangrove-trees are characterised by the possession of highly 
p?culiar pneumatophores (figs. 223, 224, 225). These are displayed in their simplest form by Carapa 
obovaia (fig. 223, 3), where the serpentine creeping roots project above the mud with their upper edge, like 
the blade of a thick knife, but studded with lenticels. In Carapa moluccensis the secondary growth in 
thickness in the upper part is irregular, so that the root terminates in finger-like outgrowths. (Pch'mper, 
p. 401). 
The young branch of the root of Carapa obovata seen at fig. 223 (3) shows admirably 
that the lenticels in a pneumatophore apparatus may be abundantly present for 
breathing purposes without either the normally-shaped pneumatophore such as we see 
in Avicennia or the stilt-root, such as we have in Bruguiera. These have been differ- 
entiated by an author in the " Journal of Heredity," quoted at p. 69, as " Ventilating 
Pores." 
Concerning pneumatophores, Schimper goes on to say (p. 403). 
That pneumatophores supply subterranean parts of the trerc upon which they occur with oxygen 
was proved by G. Karsten ar.d Greshoff, as has been already explained. All these structures are 
accordingly provided with devices for absorbing oxygen (lenticels, stomata, thin cork), ar.d for transporting 
it (intercellular passages in the primary cortex or bast). . . . 
A< u-ennia officinalis (figs. 223, 4; 224) together with two American species, Sonneralia acida and 
S. alba, Ceriops Candolleana, and the American Combretaceous Lagunculuria racemosa, all have negatively 
geotropic lateral roots protruding from the ground like asparagus ; these are as long as one's finger, or, in 
Sonneratia, one's arm. 
See also " The Mangrove of the Bombay Presidency and its Biology," by E. 
Blatter, S.J. (Journ. Bomb. Nat. Hist. Soc. xvi, 644 (1905) ) for Pneumatophores. 
This is an especially valuable paper. He follows Schimper in distinguishing 
a Western and an Eastern Mangrove (or, more fully, a Mangrove formation), the western 
one covering the coasts of Western Africa and America, and the eastern one those of 
East Africa, Asia, Australia and Micronesia. He adds Exccecaria agallocha L. to 
Schimper's list. 
He gives an account ' of Rhizophora mucronata (which he styles " The True 
Mangrove ") in some detail, and describes the long aerial roots. 
"phora mucronata forms sometimes tangled thickets by the interlacing of its roots, sometimes 
it is more isolated ; but in any n-se it :tlw:iys occurs on the outer border of the mangrove formation towards 
ihe open sea. thus serving as a protective outpost of the less favoured representatives of the same formation. 
When the tid- is (ait, the ground occupied by the mangrove shows a bluish-black mud, from which 
