CLV.— THE WOOD SPURGE. 
Euphorbia amygdaloides Linne. 
T HE most difficult problem, perhaps, that faces the systematic botanist to-day, 
in the endeavour to make the Natural System of classification more in accord 
with the facts of structure, is the placing of the apetalous Families alongside their 
true affinities. Some of them may possibly consist of persistent primitive types ; 
but the majority certainly present characters indicative rather of the degeneration, or 
comparatively recent simplification, of higher, i.e. more complex, structures. The 
Spurge Family or Euphorbiacece, for instance, the fourth largest Family among 
Flowering Plants, comprising as it does over 4,000 species in some 220 genera, 
having usually a ring of carpels, sometimes to a considerable number, which 
separate when ripe without any prolonged carpophore, have been very generally 
considered to be nearly akin to the Malvales. As, however, they have anatropous 
ovules, one or two in each carpel, with ventral raphe, it is thought that their true 
affinities may rather be with the Geraniales. 
The Family does not extend into Arctic latitudes and, though otherwise 
cosmopolitan, may have originated in the Tropics, where it is now largely represented 
by arborescent species. It is among these tropical trees that the latex, generally 
white, milky, and acrid, which forms such a striking feature of the group, is most 
abundantly secreted, although it occurs also in our British herbaceous representatives 
of the Family. This, perhaps, lends support to the view that a main purpose of 
this acridity is to protect such perennial or woody plants from the depredations 
of boring beetles. 
A very large proportion of the Family are xerophytic, this being especially the 
case with the many African representatives of the genus Euphorbia itself. These very 
generally lose their leaves and develop stipular thorns, the ordinary leaf-functions 
being carried on by the green stems and branches. Their stems may assume nearly 
spherical forms, or become deeply-ridged columns with a thickened cuticle and few 
stomata, so as to check transpiration ; and so closely do they reproduce the 
American desert forms of the CactacecB that, when not in flower, they are often quite 
difficult to distinguish from them. The interior of these stems is largely occupied 
by water-storing cellular tissue. 
The leaves in this Family are usually scattered and stipulate, and there is a 
great variety in the types of branching of the inflorescence ; but the flowers are 
generally small, and always unisexual, polysymmetric, and hypogynous. There may 
be a perianth, though it is often absent, as it is in the genus Euphorbia. Three is the 
most usual number of carpels present ; and they very generally coil up spirally 
when ripe and open so as to discharge the seeds explosively. The ovule has a fleshy 
aril round the micropyle, which persists in the seed. In the seeds or “beans” of 
