74 MISSOURI BOTANICAL GARDEN BULLETIN 
ing gum, and later paraffin was used, chicle seems to be the 
most satisfactory and has practically replaced all other ma- 
terials in the making of this popular confection. The chew- 
ing gum industry of the United States has grown to such 
proportions in the last decade that it now exceeds each year 
by several millions of dollars the value of all synthetic chem- 
icals, dyestuffs included, imported annually before the war. 
DASYLIRION SERRATIFOLIUM 
For tropical ornamentation Dasylirion serratifolium, a 
native of southeastern Mexico, is equal in many respects to 
the commonly used Yucca filamentosa except that it does 
not possess quite the same degree of hardiness. Dasylirion 
forms dense heads of glaucous leaves measuring 2-3 feet in 
length with prominently serrate, prickly margins. 
After having been transplanted into the succulent house 
from the old yucca dome, where it was annoying to all 
passers-by on account of the prickly leaves spreading out 
above the walk, it flowered for the first time in twenty years. 
The flower spike was 15 feet high, formed like a fox tail, 
with hundreds of small yellow flowers attached to the parent 
ps upon small racemes, resembling somewhat the golden- 
rod. 
POTHOS CELATOCAULIS 
The shingle plant (Pothos celatocaulis) is a tropical 
American climber commonly used in greenhouses as a wall 
covering. It fastens itself to the wall by means of hairy pro- 
tuberances radiating from the stem, the leaves being im- 
bricated in the form of shingles. 
As soon as the plant outgrows its support, large-lobed 
leaves are produced and at the same time thick roots are sent 
out, penetrating the ground. In this stage it is often mis- 
taken for Philodendron pinnatifidum with its large-lobed 
foliage. The photograph illustrates the stages from the en- 
tire to pinnatifid formation and the reverse. 
BIRD OF PARADISE PLANT 
The bird of paradise plant is so called because of the bril- 
liant and unusual color combination of its flower stalk. 
Botanically it is known as Strelitzia augusta, the genus being 
named in honor of Queen Charlotte of the Mecklenburg- 
Strelitz family, and wife of George III. This plant belongs 
to the banana family (Musaceae) and includes six species 
