Histology of Monocotyledons. 149 
In a transverse section certain of the crystal- cel Is are seen 
to be of smaller diameter, to contain fewer individual crystals 
of greater sectional area, and to be without the envelope of 
mucilage (Fig. 3). They are arranged rather differently, being 
situated near the xylem, one to three being seen in a section 
to each bundle ; odd ones also occur in the ground-tissue along 
with the ordinary raphide-cells. 
In longitudinal section, the differences are more apparent. 
The new form of crystal-sac is narrower, and contains from 
ten to twenty needles of a larger size than the numerous ones 
composing the raphide-bundles. This type of crystal-sac 
also possesses both nucleus and protoplasm (Fig. 4). 
The raphide-cell averages about 250 //. in length, and the 
individual raphide about 60 \x. The crystal-sac is very little 
longer than the crystals themselves, which average 100 /uu, 
about double the length of the raphide. 
Convallaria majalis resembles Funkia closely as regards 
its crystals, possessing in its leaves both ordinary raphide- 
cells, and sacs containing larger and fewer needles without 
mucilage. The latter are the more numerous. The roots 
and rhizomes seem only to have the mucilaginous raphide- 
cells. Hilgers 1 examined the mucilage of the raphide-cells, 
but makes no mention of the other kind of crystal-sac. In 
Polygonatum multiflorum , however, I have not succeeded 
in finding any type of crystal-cell other than the mucilaginous 
raphide-cells. 
Phormium tenax var. atropurpurea. This plant furnishes a 
more interesting case. In the leaf the crystals which attract 
attention are very similar to those found in Iris , being 
solitary prisms in cells without mucilage arranged in longi- 
tudinal rows (Figs. 5 and 6). Careful observation, however, 
also shows here and there ordinary raphide-cells. These are 
very sparsely scattered. The others are comparatively 
common, and odd ones contain two crystals instead of the 
usual solitary one (Fig. 7). 
Hilgers, loc. cit. 
