LEAVITT: TRICHOMES OF ROOT. 
299 
Liliiflorae. 
In this group a single genus, Anigozanthos of the Haemodoraceae, 
was found to exhibit specialized hair-cells. In Anigozanthos pul- 
cherrima (pi. 18, fig. 82-87; pi. 19, figs. 88, 89) the finer rootlets 
allow one to see the cells of the epidermis to the apex. At a distance 
of about 12 or 15 cells from the growing point the first fundaments 
of the trichomes may be seen (pi. 18, fig. 82). Tabular cells in 
this region are cut into unequal segments. The division walls are 
not inclined (pi. 18, fig. 83). The two segments of each mother 
cell stand to each other, as regards length, about in the ratio 2:1 or 
3 : 2. The proximal segment is the shorter ; this is the trichoblast. 
Very soon after its formation, it is seen to be richer in contents and 
darker colored than its atrichomic sister cell. The latter rapidly 
elongates, and in the roots examined, ultimately reaches an extension 
of 25 times its original length. On the other hand the trichoblast 
as a rule increases only 2 or 3 times in this dimension. The atri- 
chomic cell was seldom found subdivided. In consequence the 
epidermis usually consists of two very dissimilar elements in regular 
alternation (pi. 19, fig. 88). Frequently the trichoblast divides 
longitudinally at an early stage (pi. 18, fig. 84), so that two col¬ 
lateral trichomes arise (pi. 18, fig. 87) as in Lachnocaulon, Luzula, 
and Lycopodium. 
SciTAMINEAE. 
The following members of this family were examined, and I was 
able to assure myself that in each the trichomes are predetermined 
in the embryonic stage of the epidermis. The differentiation of the 
future hair-cells was in some cases only to be certainly determined 
from longisections of the root tip, although the distribution of the 
trichomes and their size — slightly less than that of other cells — 
was in these instances indicative of the mode of their formation. 
The nature of the hair-cells is most evident in Costus and Elettaria. 
Musaceae : Musa Cavendisliiana. 
Zingeberaceae : Costus sp. (probably spicatus ), C. afer, Elettaria 
Cardamomum (pi. 19, figs. 90,91). In the last two species 
named the exact origin of the trichoblasts, as proximal segments 
in differentiating divisions of epidermal cells, was ascertained. 
