i7 
Ridley .— The Distribution of Plants. 
later than 1906, I found two or three plants of the Bracken, but no more 
occurred on the whole plateau. It is usual in camping here to put the rice- 
bags and such baggage under the raised floor of the huts, and there can be 
little doubt that the spores were brought in the baggage to these spots. 
Bracken is often used for packing and litter for animals, and it has probably 
largely at least made its way about the world in this way. 
Trichomanes radicans , Sw., occurs over a wide area, but seems always 
to be scarce. It seems to be very variable, if all the plants included under 
its name are specifically identical, and is a plant of warm temperate regions 
which seems to have descended into the tropics along mountain chains. It 
is not known fossil, and is absent from oceanic islands. 
Lastraea thelypteris , Desv., is widely distributed, though absent from 
America, but I have some doubt as to all the specimens recorded being of 
the same species. 
Some others of the more widely distributed ferns are plants of great 
adaptability, such as Litobrochia incisa , Thunb., abundant in the dark, 
wet hill forests from 2,000 feet altitude and upwards, which I have found 
established in culverts by the roadside in the lowlands of Singapore, doubt¬ 
less an escape from the Botanic Gardens, and as the highest ascending 
plant on the bare volcanic rocks of Sibayak Mountain in Sumatra with 
a low temperature and a full sun exposure. 
Ceratopteris thalictroides , Linn., is an aquatic in ditches in the tropics, 
the spores perhaps borne about by water-fowl, and Acrosticlmm aureum , 
Linn., is a tidal-mud plant widely spread along the tidal rivers. Both 
these plants, by virtue of their peculiar habitats, have no fern competitors 
to contend with. 
Ferns like some of the Adiantums and Cheilanthes farinosa , Kaulf., 
which have wide distributions, are popular garden plants, which have 
established themselves in many localities. 
As ferns have an exceptionally favourable dispersal method in their 
minute spores and much less exigence in the matters of fertilization and 
habitats than flowering plants, it is extraordinary that species of an order 
of such undoubted antiquity should have such limited area of distribution as 
they do at present, if age was any qualification for extent of area. 
The most widely distributed Flowering Plants. 
I now deal with the most widely distributed Phanerogams exclusive 
of sea-borne species and weeds. 
The most extensively distributed flowering plant in the world is, I believe, 
the Common Reed, Phraginites communis , Trin. I include under it P. 
Karka ( P . Roxburghii), as I fail to see any real distinction between 
the plant of the temperate region and that of the tropics. The Reed 
ranges all over Europe, Asia, Africa, America, and Australia, but appears 
C 
