BOTANIC MATERIA MEDICA. 487 
Xanthidium—zan’-thid-i-um, plural, Xan- 
thidia (from zanthos, yellow), A very minute 
plant of a globular shape and with many 
spines, only to be seen with a microscope. 
Xanthine—zan’-thin (Gr. zanthos, yellow; Fr. 
xanthine). The yellow, insoluble material 
found in many plants and flowers. 
Xanthophylline—zan’-thof-il’-lin (Gr. zanthos, 
yellow, and phullon, a leaf), The yellow col- 
oring of the leaves in autumn is due to this 
material. 
Xylocarp—zi’-lo-karp (zu/on, wood, karpos, 
fruit). Relating to fruits with a woody texture, 
or fruits that become hard and woody, xylo- 
carpous, 
Yarrow—yar’-ro (As. gearwe). The achilea 
milefolium belongs to the Composite order 
of plants; used as a medicine. : 
Yeast—yest, oascht, froth of beer (As. gist, 
yeast, a blast of wind; Dutch gest, yeast; 
probably from the Gr. zestos, ferment), The 
Cerevisiz Fermentum; used for raising _ 
dough for bread, the ‘orula cerevisie, a spe- 
cies of fungi. 
Yerba—yer’-ba (Spanish, yerba, from the Lat. 
herba, an hee A name applied to many 
small plants or shrubs, as the Yerba Santa, 
etc. 
Zoophyte—zo’-o-fit (Gr, soon, an animal, and 
phuton, a plant). A body resembling in many 
particulars the animal and vegetable. _ 
Zoospores—zo’-o-sporz (Gr. 200m, an animal, 
and spora, seed). Applied to the active 
spores of sea-weed or algee which appear to 
be endowed with voluntary motion, 
