144 Sargant. — The Reconstruction of a Race of 
of the closed type, which is universal in the mature Monocotyledon, or the 
amphivasal form which is characteristic of it. 
Traces of a cambium in the vascular bundles of Monocotyledonous 
seedlings have been recorded by several observers. Miss Anderssohn ( 1 ) 
in 1887 figured a cambium within the bundles of seedlings belonging to 
thirteen species. The tissue is clear in all her figures : it would seem best 
marked in Zea } Typha , Lilium , and Dracaena . Among my own prepara- 
tions there are ten well-marked instances from eight genera. I found the 
greatest development of cambium in the hypocotyl of Yucca arborescens. 
It is quite clear in the same region of two other species in that genus, 
Y. gloriosa and Y. aloifolia . Cambium appears also in cotyledonary 
bundles of Milla , Dipcadi , Galtonia , Albuca , and Fritillaria . Elettaria 
and Musa show it in the traces of the first and second leaves. 
The cambium in all these forms is very transient. It is not seen 
in the very young bundle, where the protoxylem is only just lignified. 
Such a bundle is often wedge-shaped in transverse section. The lignified 
protoxylem is at the sharp angle of the wedge, a group of scleren- 
chyma at the broad -end, and just within the sclerenchyma a few 
elements of ‘ soft bast ’. Between protoxylem and protophloem is an 
ill-defined region, of which the elements bordering on the protoxylem 
will become metaxylem, and those adjacent to the protophloem will form 
more phloem. Before this process is complete, three or more rows of 
cells between phloem and xylem will often be found in radial series. The 
innermost rows will be added to the metaxylem. the outermost to the 
phloem. Divisions in this region soon cease, and alterations of shape and 
size — perhaps a few irregular divisions too — in the elements added to 
the bundle usually destroy the original radial sequence. When this has 
disappeared, no trace is left of the formation of cambium. 
Professor Queva has worked out the anatomy of Gloriosa superba , 
a tropical Liliaceous climber, from germination to maturity ( 65 ). The 
plant produces fresh aerial stems every year. They die down at the end 
of each growing season. The perennial organ is a V-shaped tuber, which 
is simply a branched and thickened segment of the stem. The tuber lasts 
through two seasons. In the first it is formed on the parent tuber and 
grows to its full size. In the second it renews its growth, giving rise to 
two aerial stems and two new tubers. This activity exhausts the food 
laid up in the first year, and brings about the death of the tuber. 
The bundles of the seedling stem possess a short-lived cambium, which 
adds phloem and xylem elements to the complete structure (Queva, 
p. 102). Traces of its activity are soon obliterated by subsequent divisions 
in the secondary elements, and by irregularities of growth which destroy 
their original arrangement in rows. The bundles of the stem -segment 
which becomes the tuber of the seedling plant have lost all traces of 
