84 LEAFLETS Or PHILIPPINE BOTANY [Vor. I, Ant" T 
ologists record about 1,000 genera containing over 12,000 spe- 
cies, or one tenth of all known Phaenogams. This vast 
number of species is distinguished more or less by minor 
characters, but there is no species over which there can be 
any doubt as to its family. The dry seed achene with or 
without pappus is common to all. The origin and history 
of this family is obscure, but there is a general opinion 
that it represents the most highly developed group in the 
vegetable kingdom. The great diversity of localized forms 
tends to indieate a very remote origin, although our first 
reliable fossil records belong to the Miocene period of the 
Tertiary era. However, it must be remembered that most 
of the species are herbaceous and none aquatic—conditions 
not favorable to permanent preservation. Economically the 
family ranks extremely low in its direct usefulness to man. 
In fact a great many of its species are troublesome weeds, 
rapidly spreading through unintentional introductions. None 
of them afford green or dry feed, despite the fact that most 
of them are herbaceous. Nor do we find among them trees 
large enough for lumbering. A number of species yield 
seeds that are used as foods and from which certain oils 
are extracted. Young foliage of many species and varieties 
is used in salads, and the tuber of a few is edible. 
Quite a variety is grown for ornamental purposes. Some 
are cultivated for their coloring material, and many have 
medicinal properties. : 
FAMILY CHARACTERS. 
Herbs or shrubs, rarely trees, with watery, resinous or 
milky sap, and alternate or basal, rarely opposite or whorled 
entire, lobed or pinnatifid simple or compound leaves; stip- 
ules none. Flowers perfect, pistillate or neutral, or sometimes 
monecious or dioecious, borne on a common receptacle, form- 
ing heads, subtended by an involucre of few to many bracts 
arranged in one or more series. Receptacle naked, or with 
chaffy scales subtending the flowers, smooth or variously 
pitted. Calyx tube completely adnate to the ovary, the 
limb (pappus) of bristles, awns, teeth, scales, or crown like, 
or cup like, or wanting. Corolla of two forms, the first tub- 
ular or campanulate, 4 to 5-lobed; the lobes valvate and 
