386 VARIOUS PLANT GROUPS 
ous bristles forming what is termed the pappus.1 Sometimes 
through a prolongation of the torus above the fruit a sort of 
parachute is formed as in lettuce (Lactuca, Fig. 76). The 
one-seeded fruit of Composit# is commonly called an achene, 
although morphologically it is very different from such a 
simple achene as that of the crowfoots. 
In spite of wide diversities in structural detail the members 
of this vast family may generally be recognized as herbs with 
milky or watery juice; flowers in dense heads having a calyx-like 
involucre, gamopetalous, regular or irregular; stamens five, 
syngenesious, but with distinct filaments inserted on the corolla, 
and the pollen-sacs straight; ovary inferior, with a single ovule; 
fruit achenial, often with pappus. 
140. The bellflower order (Campanulales), includes several 
families with flowers perfect, imperfect, or neutral, regular or 
irregular, mostly gamopetalous; the stamens five, adherent to the 
corolla, distinct or more or less coherent; anthers not poricidal; 
ovary compound, inferior. 
The formula of Campanulales is given on pages 420, 421. 
141. The bellflower series (Metachlamydez) in contrast 
with the crowfoot series or Archichlamydez, includes several 
orders which are characterized by the prevalence of a gamo- 
petalous corolla. This, as showing a more advanced develop- 
ment of the perianth than we find in archichlamydeous flowers 
(see section 129), entitles the flower possessing it to be dis- 
tinguished as metachlamydeous.? 
142. The dicotyl sub-class (Dicotyledones) comprises the 
crowfoot series (Archichlamydez) and the bellflower series 
(Metachlamydex). These agree in being made up of seed 
plants with the embryo having two cotyledons or dicotyled- 
onous.2 The parts of the flower are very generally in fours 
or fives, seldom in threes; the leaves are mostly netted- 
veined; and in the stem there may be distinguished a central 
core of pith surrounded by a ring or rings of wood and bark. 
See especially Figs. 232 and 233. Stems thus constructed 
1Pap’-pus > Gr. pappos, grandfather, applied to the thistledown in 
allusion to white hair. STCj. 
2 Met’-a-chla-myd’’-e-ous < Gr. meta, beyond. 
3 Di’’cot-y-led’on-ous < Gr. dis, two; pe teton: seed-leaf. 
