L VII. — THE MARSH SAMPHIRE. 
Sa/icornia herbacea Linne. 
F EW of the Polygonacea- , even when their perianth does consist of two whorls of 
leaves, show much differentiation towards the calyx and corolla of higher 
types. The coloured, nectariferous, and dimorphic flowers of some species of 
Polygonum do, however, suggest the beginnings of more specialised forms ; and, 
when its characters are set down in the necessarily general terms true of most of its 
varied Families, there is but little to show Engler’s tenth Order, the Centrosperm<e, to 
be higher than Polygonales. This Order consists mainly of herbaceous plants, 
the flowers of which may present the more primitive acyclic arrangement or be 
whorled ; and have sometimes a perianth with no distinction between its whorls ; and 
at others a distinct calyx and corolla. Their stamens vary from one to an indefinite 
number ; but their frequent position in front of the perianth-leaves suggests that 
there are degraded types included. The carpels also vary in number ; but they are 
mostly syncarpous, and the most general characters of the Order are the one- 
chambered ovary with central placentation and the embryo curved round the 
perisperm. One can hardly hesitate in considering the Chenopodiace<e as the lowest of 
the Families included in this Order and the Caryophyllacea as the highest. 
The Chenopodiace <e are not a large Family, only comprising some 500 species in 
about seventy-five genera ; but they are widely distributed over the shores, deserts, 
and steppes of the world, many species also occurring as weeds in cultivated land. 
This distribution is the result of their exceptional power of absorbing alkaline salts, 
especially, it would seem, nitrates of potash and soda. The cooling taste of the 
leaves of the various species cultivated as spinach, and the former use of others, such 
as Salsola and Salicornia, in the preparation of barilla for the manufacture of glass, 
both result from this function. When plants are surrounded by large quantities of 
salts in the soil and have this power of absorbing them, it is necessary, in order to 
avoid concentration, that transpiration should be reduced ; and many Chenopodiace <e 
accordingly have fleshy leaves, or are covered with hairs or with a mealy excretion. 
Whether inhabiting dry deserts or saltings, where they are covered at every high 
tide by the waters of the ocean, they are alike structurally and physiologically 
xerophytes. They have generally branched tap-roots ; scattered, simple, exstipulate 
leaves ; and small, inconspicuous flowers with a persistent perianth of one whorl only, 
of sepaloid leaves, five or less in number, and as many or fewer stamens, opposite the 
leaves of the perianth. The ovary is superior, one-chambered, and one-ovuled, and 
forms a dry achene in the fruit stage, the solitary ovule rising from the base of the 
ovarian cavity. When both stamens and carpels occur in one of these small flowers 
it is probably self-pollinating : in other cases the pollen may be carried by crawling 
insects or by the wind ; but the flowers have in general neither honey nor other 
special adaptation for any method of cross-pollination. 
