TAXONOMY 
3*7 
Caricacece or Papaw Family. — A family of latex-containing trees 
composed of two genera indigenous to tropical America. Of chief 
pharmaceutic interest is the species Carica Papaya, the Papaw or 
Melon tree, the fruit of which yields Papain, a valuable digestive 
ferment. This plant is a tree about 20 feet high which bears at its 
summit a cluster of deeply lobed petiolate leaves and dioecious flow- 
ers. The fruit is a berry, the size of one’s head and contains an acrid 
milky juice from which papain can be precipitated by the addition 
of alcohol. 
Cistacece or Rock Rose Family. — Herbs or shrubs whose stem and 
branches are often glandular, pubescent or tomentose, with simple 
or stellate trichomes. Leaves simple, entire, the lower ones opposite, 
upper alternate. Flowers perfect, regular, terminal, and solitary 
or in cymes or unilateral racemes; sepals five, the two external ones 
often bractiform or wanting; petals five {H elianlhemum) rarely three 
or none { Lechea ); stamens hypogynous, indefinite; carpels three to 
five, ovary free, one-celled. Fruit a one-celled three- to five-valved 
capsule. 
Official drug Part used Botanical origin Habitat 
Helianthemum Herb Helianthemum Eastern United 
N.F. canadense States 
XX. Order Opuntiales. — Cactacece or Cactus Family. — Herba- 
ceous rarely arborescent ( Cereus giganteus) more or less succulent 
plants living in warm dry {Peireskia) usually desert situations, rarely 
becoming epiphytic and correspondingly modified. Stems accord- 
ingly varying from elongate, slightly enlarged, green ( Peireskia ) to 
flattened ( Cereus and Opuntia) to condensed [Echino cactus , Echino- 
cereus, etc.) to greatly condensed ( Mamillaria ). Leaves alternate, 
stipulate or exstipulate, enlarged and more or less fleshy (. Peireskia ) 
becoming reduced green and semicircular ( Opuntia ) or modified into 
spines or wholly absorbed. Flowers, regular, solitary or fascicled in 
axils of leaves; sepals five; petals similar to sepals, petaloid, small to 
much enlarged, in color varying from yellow to white or from yellow 
to yellowish-pink, pink, scarlet or crimson; stamens indefinite in- 
serted at varying levels in the throat of a greatly expanded upgrown 
receptacle; pistil generally tricarpellary; ovary inferior, often 
