McDonald : T/ie Dog's Mercury. 



267 



stiff one, and from six to twenty tough roots grow downwards 

 from ever}^ node, so that this dense net work of roots and stems 

 makes it very difficult for any other plant to grow beneath them. 



When expanded, the decussately arranged leaves are seen 

 to be oblong, lanceolate, serrate, and stalked, with two small 

 subulate stipules at the base of each. On the underground 

 portion of stem, and towards the base of the aerial portion, 

 neither foliage leaves nor stipules are developed, only scale- 

 leaves whose office is that of protecting the delicate apex wMst 

 it is making its way through the soil (Fig. 7). Both stem 

 and leaves are hirsute. Like the leaves of many other shade- 

 loving plants, their epidermal cells contain some chlorophyll 

 granules, as in such cases they have not to be protected from 

 excessive light. 



As previously stated, the flowers are of two kinds, occurring on 

 separate plants belonging to separate colonies, and though of a 

 somewhat simple character compared with others belonging 

 to the same natural order (Euphorbiaceae) they are pregnant 

 with interest. 



They are arranged on spikes which arise from the axils of 

 some of the low^er foliage leaves. The staminate (male) spikes 

 bear a number of flowers arranged in little definite clusters 

 (glomerules) see diagram.s (Figs. 21 and 22). Each staminate 

 flower consists of a green three-lobed perianth, and from nine 

 to twelve, occasionally a few more, stamens with rather long 

 filaments, the dilated connective bearing two nearly globular 

 anther lobes (Fig. 10). The pistillate spikes are few-flowered, 

 each flower has a similar perianth, a two-lobed and two-celled 

 hirsute ovary, each cell containing one pendant inverted 

 (anatropous) ovule. On the summit of the ovary are two 

 curved styles, their upper or stigmatic surfaces being warty. 

 Alternating with the lobes of the ovary, that is one on each side, 

 are two awl-shaped filaments, which are usually looked upon 

 as degenerate stamens (staminodes) (Fig. 12.) 



Kerner makes the remark that no structure however 

 inconspicuous in any plant, but has some function or it would 

 not be retained. To the writer it was a puzzle for a long time 

 what the function of these staminodes could be, and the solution 

 came as a surprise and unexpectedly. 



To any additional organ in a flower other than perianth, 

 stamens, or pistil, Linnaeus applied the term nectary, and this 

 term was applied to the staminodes in the pistillate flowers of 



igo July I. 



