978. Order Gentianales.—Herbs, shrubs, vines, or trees. Six families in the United States.
The olive family (Oleaceæ) includes the common lilac (Syringa), the ash trees (Fraxinus), the privet (Ligustrum).
The gentian family (Gentianaceæ) among other genera includes the gentians (Gentiana).
The milkweed family (Asclepiadaceæ) contains plants mostly with a milky juice. Asclepias with many species is one of the most prominent genera.
979. Order Polemoniales.—Mostly herbs, rarely shrubs and trees. Fifteen families in the eastern United States.
The morning glory family (Convolvulaceæ) includes the bindweeds (Convolvulus), the morning glory (Ipomæa), etc.
The dodder family (Cuscutaceæ) includes the dodders, or “love-vines.” There are nearly thirty species in the United States. The stems are slender and twine around other plants upon which they are parasitic ([see paragraph 179]).
The phlox family (Polemoniaceæ). The most prominent genus is Phlox. Over forty species occur in North America.
The borage family (Boraginaceæ) includes the heliotrope (Heliotropium), the hound’s-tongue (Cynoglossum), the forget-me-not (Myosotis), and others.
The vervain family (verbenaceæ) contains the verbenas.