400 
GENTIANA 
series of flrs., adapted to higher and higher types of insects. The more 
common sp. may be thus grouped (biologically and to a large extent 
morphologically) : 
Ancestral type. 
G. lutea L. Eugentiana Gentianella. 
I 1 
§ Coelanthe (humble- § Crossopetalum 
bee firs.). (humble-bee flrs.). 
1 I 
§ Cyclostigma (Lepi- 
doptera flrs.). 
§ Endotricha (Lepid. 
and humble-bee flrs.). 
In G. lutea L. the honey is freely exposed (p. 89), the corolla being 
rotate ; the visitors are mostly short-tongued. The colour too is yellow 
(p. 100) and the flr. is homogamous. To § Coelanthe belong G. pur- 
purea L., G. Pneumonanthe L ., &c. The latter sp. (Brit.) has a blue 
corolla with a long tube, is protandrous and visited by humble-bees 
(class H, p. 92). To § Cyclostigma belong G. bavarica L. , G. verna L., 
G. nivalis L., &c.; G . verna (Brit.) resembles G. Pneumonanthe but has 
a still longer and narrower tube and is visited by Lepidoptera. Turning 
to the other division, we find similar phenomena. G. ciliata L. 
(§ Crossopetalum ) is a protandrous bee-fir., G. Amarella L. (Brit.; 
§ Endotricha ) a homogamous bee- and Lepidoptera-flr. G. campestris 
L. (Brit.) is similar. This sketch of the probable course of evolution 
of the gentians is of course hypothetical, but not more so than most 
hypotheses of the evolution of existing forms of life. It is a good 
illustration of the general argument of the Theory of Flowers set forth 
on pp. 87 — 94, which should be carefully read in connection with 
this article. 
The gentians form one of the most striking features of the flora 
of the Alps, occurring in large masses and with very conspicuous 
flrs. ; G. acaulis L. is the most beautiful. In the Brit. Mts. they are 
rare. The root of G. lutea furnishes a tonic. 
Gentianaceae. Dicotyledons (Sympet. Contortae). 64 gen. with 7 50 sp. 
The order has representatives in every part of the globe and in a great 
variety of situations — arctic and alpine plants, halophytes, sapro- 
phytes (Voyria, &c.), marsh plants (Menyanthes, &c.), water plants 
(Limnanthemum), &c. They are mostly herbaceous plants (often 
perennial), but a few shrubs occur. The perennial herbs have 
usually a rhizome. Leaves opp., exstip., usually entire. The infl. 
is usually a dichasial cyme like that of Caryophyllaceae ; as in 
that order, the lateral branches often become monochasial. Other 
cymose infls. also occur. Bracts and bracteoles present or not. 
Firs, regular, 5? , 4— 5-merous (rarely more). K usually (5), imbri- 
