MEMORANDA. 207 
grace and their next allies, and yet less simple and sure, 
than any single character hitherto employed. Thus, too, 
we could determine the affinities and contrasts of certain 
plants by a method at once easy, novel, and practical, and all 
this in the absence of those parts heretofore exclusively used 
for the descriptive distinctions. And there would be another 
advantage in enlisting these crystals into the service of 
systematic botany; for we should not be thus employing 
merely an empirical formula, but methodically recognising 
some really fundamental results of plant-life, well fitted to 
keep before us such interesting and important phenomena in 
the economy of vegetation as must be especially valuable in 
a natural system of classification.— Annals of Nat. Hist., Oct., 
1863. 
Onagracee.—This order, as shown in former papers, is so 
well and truly characterised in this manner, that the raphides 
even in the seed-leaves may be sufficient for the diagnosis; 
and I know not that it had ever before been suspected that 
this rudimental part of the plant of one order would thus be 
adequate to distinguish it from the other plants of the nearest 
allied orders. 
Further, I have now to observe that the same difference 
may be demonstrated in the ovule. In its sacs and in the 
placenta the raphides abound, whilst they do not exist there 
or elsewhere in plants of cognate orders. Though I have 
made a few observations to this effect in other raphidiferous 
plants, I have chiefly studied the facts in Onagracez, because 
these are easily obtained, germinate freely, abound so much 
in raphides, and stand in the natural system between orders 
not thus producing raphides. 
Thus, taking the order Onagracee as a typical raphidiferous 
one, we have shown the presence regularly of raphides through 
every part and period of growth of the vigorous plant, from 
the ovule, cotyledons, axis, leaves and their modifications, to 
the parts of fructification, and, finally, to the pulp of the 
berry. In most, if not all, species of the order, the raphides 
occur more or less in the anthers, filaments, style, and stigma, 
and, less plentifully, in the petals. 
Discoreacee.—The raphides are sometimes so very distinct 
and beautiful in this order, that they would be excellent 
examples for demonstration at lectures. By simply drying 
on glass some of the juice of the berry of Tamus communis, 
the raphides may be preserved for an indefinite time; and, 
as they are about =1,th of an inch long and ;,'>,th ich 
thick, they may be seen merely with the aid of a common 
