Most remarkable fungus-like forms may be obtained by commencing the growth in a concentrated solution, and then {134} carefully pouring a layer of distilled water over the surface of the liquid. The resemblance is so perfect that some of our productions have been taken for fungi even by experts. The {135} stem of these osmotic fungi is formed of bundles of fine hollow fibres, while the upper surface of the cap is sometimes smooth, and sometimes covered with small scales. The lower surface of the cap shows traces of radiating lamellae, which are sometimes intersected by concentric layers parallel to the outer {136} surface of the cap. In this case the lower surface of the cap shows a number of orifices or canals similar to those seen in many varieties of fungus. [Illustration: FIG. 45.--A shell-like calcareous osmotic growth.] [Illustration: FIG. 46.--Osmotic growths in the form of shells.] [Illustration: FIG. 47.--Capsular osmotic growth. The capsule has been broken to show the interior structure.] Shell-like osmotic productions may be grown by sowing the mineral in a very shallow layer of concentrated solution, a centimetre or less in depth, and pouring over this a less concentrated layer of solution. By varying the solution or concentration we may thus grow an infinite variety of shell forms. {137} Capsules or closed shells may be produced in the same way by superimposing a layer of somewhat greater concentration. These capsules consist of two valves joined together at their circumference. The lower valve is thick and strong, while the upper valve may be transparent, translucent, or opaque, but is always thinner and more fragile than the lower one. Ferrous sulphate sown in a silicate solution gives rise to growths which are green in colour, climbing, or herbaceous, twining in spirals round the larger and more solid calcareous growths. [Illustration: FIG. 48.--An osmotic growth in which the terminal organs are differently coloured from the stems, showing that the chemical evolution is different.] With salts of manganese, the chloride, citrate or sulphate, the stages of evolution of the growth are distinguished not only by diversities of form, but also by modifications of colour. We may thus obtain terminal organs black or golden yellow in colour on a white stalk. In a similar way we may obtain fungi with a white stalk and a yellow cap, of which the lower surface is black. [Illustration: FIG. 49.--Osmotic capsular growth with figured belt.]