232 
Convolvulus, Ch. 
Aniseia, Ch. 
Porana, L. 
Dinetus, Sweet. 
Neuropeltis, Wall, 
Prevostea, Ch. 
Dethardingia, Nees. Evolvulus, L. 
Reinwardtia, Spr. ? Wilsonia, R. Br. 
Polymeria, R. Br. 
Calystegia, R. Br. 
Shuteria, Ch. 
Calycobolus, W. 
Dufourea, H. B. K. 
Breweria, R. Br. 
Bonamia, Thouars. Mouroucoua, Aubl. 
Cressa, L. 
Skinneria, Ch. 
Order CLXXVII. POLEMONIACE^ 
The Greek Valerian Tribe. 
PoLEMONiA, Juss. Gen. 136. (1789). — Polemonide.^:, DC. and Duty, 329. (1828). — 
PoLEMONiACEiE, Lindl. Sy7iGps. 168. (1829) ; Bentham in Bot. Reg. 1622. {Oct. 
1833). 
Essential Ch.\racter. — Calyx inferior, monosepalous, 5-parted, persistent, some- 
times irregular. Corolla regular, S-lobed. Stamens 5, inserted into the middle of the 
tube of the corolla, and alternate with its segments. Ovary superior, 3 celled, with a few 
or many ovules ; simple ; a trifid ; orwZes ascending or peltate. 3 -celled, 
3-valved, few- or many-seeded, with a loculicidal or septicidal dehiscence ; the valves 
separating from the axis. Seeds angular or oval, or winged, often enveloped in mucus, 
ascending ; embryo straight in the axis of horny albumen ; radicle inferior ; cotyledons 
elliptical, foliaceous. — Herbaceous plants, with opposite, or occasionally alternate, com- 
pound, or simple leaves ; stem occasionally climbing. 
Affinities. The ternary division of the ovary connected with the pen- 
tandrous corolla and 5-lohed calyx bring this order near Convolvulacese, from 
which the habit, embryo, and corolla, distinguish it ; from Gentianacese, to 
which it also approaches, the 3-celled ovary di^'ides it. It is remarkable for 
the blue colour of the pollen, which is usually of that hue, whatever may be the 
colour of the coroUa. In Collomia linearis I have noticed (in Botanical 
Register, folio 1166) that the dilatation of the mucous matter in w^hich the 
seeds are enveloped, and which, when they are thrown into water, forms 
around them like a cloud, depends upon the presence of an infinite mul- 
titude of exceedingly delicate and minute spiral vessels, lying coiled up, 
spire within spire, on the outside of the testa ; when dry, these vessels are 
confined upon the sm*face of the seed by its mucus, without being able to 
manifest themselves ; but the instant water is applied, the mucus dissolves 
and ceases to counteract the elasticity of the spiral vessels, which then dart 
forward at right angles with the testa, each carrying with it a sheath of mucus, 
in which it for a long time remains enveloped as if in a membranous case. 
The order has been remodelled by Bentham in the place above quoted. 
Bartling refers Retziaceae to Convohiilaceae, from which he distinguishes them 
by their polyspermous cells and straight embiyo. Ord. Nat. 192. 
Geography. Very abundant in both North and South America, in tem- 
perate latitudes, particularly on the north-west side. It is stated by Richard- 
son, that the most northern limit in North America is 54®. Edin. Phil. Journ. 
12. 209. In Europe and Asia they are much more uncommon. They are 
unknown in tropical countries. 
Properties. None, or unknown. 
GENERA.* 
Polemonium, L. 
Phlox, L. 
Hugelia, Benth. Leptosiphon, Benth. Dactylophyllum, Bent. 
Linanthus, Benth. Fenzlia, Benth. 
* For this list 1 am indebted to Mr. Bentham. 
