BOTANY OF THE CEYLON PATANAS. 457 
It is interesting to note that the other species of both Atylosia 
and Hedyotis, viz., A. Candollei and H. verticillaris respectively, 
do not possess these sacs. 
(2) Thick-walled Spongy Tissue in the Leaf of Mussenda 
frondosa.—This leaf is remarkable in having relatively very 
thick-walled spongy mesophyll-cells (Pl. 11. fig. 10, tw.). These 
walls hardly seem to be mucilaginous in nature, for they neither 
swell in water nor stain with corallin-soda. Again, they do not 
appear to be composed of ordinary cellulose, as neither Schultze’s 
solution nor iodine and sulphuric acid stains them the character- 
istic blue colour, but they remain for the most part unchanged. 
(3) Crystals—Notes have been made of the crystalline 
contents of these plants, but very few of these need be recorded. 
Hxacum zeylanicum bas single crystals of calcium oxalate in 
its leaf. This is noteworthy, since it is asserted by Solereder * 
that no crystals have been observed in the order Gentianacee. 
The leaves and stems of this plant also show in the spirit- 
material crystalline spheroidal masses, which to the naked eye 
appear as white specks dotted all over the specimens. These 
are insoluble in hot and cold water and in dilute mineral acids, 
but soluble in potash and concentrated sulphuric acid with yellow 
coloration. The substance is probably a glucoside, and may be 
akin to hesperidin. In the living tissue it is most likely in 
solution, the precipitation being caused by the alcohol. 
Raphides, as is well known, occur frequently in the Rubiacez, 
but attention does not seem to have been called to the fact as to 
whether they may be imbedded in mucilage or not. Of the 
raphide-containing species, Knoxia platycarpa var. hirsuta and 
Hedyotis Lawsonie have mucilage as well, while Hedyotis 
verticillaris, Alleophania decipiens, aud Oldenlandia Heyne are 
wanting in this substance. The raphide-mucilage may be of 
value in retaining water, and so be considered a xerophytic 
character. 
(4) Reserve Carbohydrates.—As might be expected, sphero- 
crystals of inulin were found in the spirit-preserved roots, and 
sometimes in the lower part of the stems of the following 
Composite, viz. :— Vernonia Wightiana, Lagenophora Billardiert, 
Microglossa zeylanica, Blumea flexuosa, B. crinita, Anap halis 
marcescens, and A. oblonga, and also of Lobelia nicotianiefolia. 
Reserve starch in all these cases was absent. 
* — Solereder, Syst. Anat. Dicot. (1899) p. 291. 
