Cow-tree, a name given to a number of trees of different natural orders, the bland milky juice (Latex, q.v.) of which is used instead of milk. The most famous of these is the Palo de Vaca of the Cordilleras and Caraccas (Galactodendron (Brosimum) utile), an artocarpaceous tree, with large laurel-like leaves and very small flowers. The milk is obtained by piercing the bark of the trunk or branches, and flows so freely that an ordinary bottle may be filled in half an hour. The milk has an agreeable creamy odour and taste recalling that of cow's milk, but is slightly viscid and soon becomes yellow, gradually thickening into a somewhat cheesy consistency. Its chemical composition, of course, widely differs from that of milk, but its nutritive value is considerable. It is much used by the negroes and Indians.
The cow-tree or Hya-hya of Demerara is Tabernæmontana utilis, a tree belonging to the Asclepiadaceæ. In this order the milky juice is usually acrid and poisonous, and even that of other species of the same genus is of sharp and burning taste. In this case, however, the latex is agreeable and wholesome, although somewhat sticky, owing to the large proportion of caoutchouc.