238 
surface, or even stellate, from projections there of the crys- 
talline angles or tips of the prisms ; and frequently occur, 
very regularly disposed, in a perfect network of cells, which 
I call Sphseraphid Tissue, and a pretty one it is, engraved 
in the ‘Annals of Natural History’ for September, 1863, 
plate iv, fig. 13. Sometimes each of the sphaeraphides seems 
to be connected by a slender pedicle to the inside of the cell- 
wall, and then noticed by Continental writers as a ‘ cysto- 
lith.’ Meyen, I think, originally described this organism in 
Ficus ; the presence in many other allied plants of such 
crystals was observed by Payen ; Weddell called them ‘ cys- 
toliths,’ and insisted on their value as a diagnostic character. 
Great are the merits of the brothers Quekett, who distin- 
guished sphaeraphides under the name of ‘ conglomerate’ 
raphides, and added greatly to our knowledge of this branch 
of Phytotomy. They are generally by other writers con- 
founded with and simply designated as ‘ raphides/ 
Sphaeraphides are very common and widely diffused in 
Phanerogamia, as may be easily witnessed among our Caryo- 
phyllaceae, Geraniaceae, Lythraceae, Haloragaceae, Chenopo- 
diaceae, Urticaceae, and a host of other British plants. The 
leaves or stem of the Hop, Nettle, Pellitory of the Wall, and 
many T Goosefoot-weeds, are good plants for sphaeraphides ; 
and the cystoliths may be successfully examined with the aid 
of an objective of an eighth of an inch focal length in these 
first three species. The leaves of the Mulberry will also 
answer this purpose ; and the sphaeraphides are pretty in the 
fruit-capsule of the Elm, as well as in many parts of the 
Sandworts, Spurrey, and Saxifrages. The sepals of the 
Loosestrife and Geraniums, and many other common and 
native plants, afford good examples of the sphaeraphid tissue ; 
but it is far more remarkable in the inner layers of the bark 
of Aralia spinosa, a North American shrub, long and Avell 
known on our lawns. 
And indeed sphaeraphides are much larger, forming even a 
weighty grit, in many exotic species, as is notorious in Cac- 
taceae. Magnificent sphaeraphides are those of the ‘ Prickly 
Pear/ often for sale at the fruiterers ; and they are well seen, 
though smaller, in the petioles of the Passion Flowers, 
throughout the potherb called New Zealand Spinach, and in 
the North American or false Sarsaparilla ( Aralia nudicau/is) 
of the shops. 
III. Crystal Prisms are acicular forms with well-marked 
faces and angles both on the shafts and tips. These prisms 
neither occur in bundles, nor loosely in a cell or other space. 
