Ridley .— The Distribution of Plants. 23 
over or up to the ranges of hills in the interior, at least later than Mesozoic 
times, but there are a few cases of strand plants being found inland a long 
way from the present sea-coast. Thus at Kanga, in Perlis, at the base of 
the huge limestone islands now far off the sea in a great sandy plain, I found 
the little Boerhaavia repanda , Willd. (Nyctagineae), a typical sea-sand 
plant, while in the damper spots of the plains grew Dolichandrone Rheedii , 
Seem., a typical tidal-mud plant. Here the whole area, at no great distance 
of time submerged by the sea, had gradually silted up with the sand and 
gradually pushed the sea-coast far away, while these plants still remain and 
thrive stranded as they were by the departure of the sea. I have met with 
Boerhaavia repens , Linn., too, growing between the railway lines far inland 
in Java at Muntilan. Here I imagine it was brought in the ballast for the 
line. On a cart-track in Bukit Tangga, Negri Sembilan, thirty-six miles 
from the sea, and on railway banks in Kota Bharu, Kelantan, I have seen 
in sandy spots the sea-shore Convolvulus, Ipomoea biloba , well established 
though far away from its ordinary sea-sand habitat almost within the 
splash of the waves. Here again I have little doubt that it was brought in 
ballast from the sea-coast to which the railway ran, and contrived to 
establish itself on the sandy fields near the railway. But, except for these 
cases, it is remarkable to what a short distance the strand flora goes inland, 
even in such apparently favourable localities as the sandy heaths of Pekan, 
in Pahang, where the sandy cbuntry runs continuously to the strand-flora 
region. 
As a rule, sea-shore plants and tidal-mud plants disappear altogether 
when, by deposit of silt or shifting of the tidal river, the ground they grow 
on ceases to be suitable for the strand flora. The Singapore river at 
Tanglin, from road-making, town-building, &c., has long ceased at this point, 
about four miles from the sea, to be tidal, and all the waste ground in the 
economic gardens near it was a low swampy patch covered with a wood of 
Cinnamomum tilers, Bl., Premna foetida , Reinw., Macarangas, Ficus , &c., 
but when it was cleared a large clump of the tidal-mud fern Acrostichum 
aureum was found still growing there, and the ground was full of Nipa 
palm fruits, which last a very long time underground, showing that this 
must have been at one time a tidal-mud river. I once came across in Johor, 
near Gunong Pantai, a long way from any tidal mud and surrounded by 
dense forest, a large patch of the tidal-mud fern which must have marked 
a long-disappeared tidal river filled up and covered with heavy hill and 
lowland forest. These stranded sea-shore plants do not seem to spread at 
all, but remain, for the most part at least, in the same spot where they were 
left when abandoned by the salt water. 
Dolichandrone Rheedii , Seem. (D. spathacea , Schum.), mentioned above, 
is rather an interesting plant from another point of view, as shown by 
Sprague’s account of the genus in ( ; Kew Bulletin’, 1919, p. 304. The genus, 
