Advancement of Science. But the fact appears to have 
long been familiar to the hunters who traversed the prairies 
in which this plant abounds. The account was somewhat 
discredited at the time, by the observation that the plants 
cultivated in the Botanic Garden at Cambridge, U.S., did 
not distinctly exhibit this tendency. But repeated obser- 
vation upon the prairies, with measurements by the compass 
of the directions assumed by hundreds of leaves, especially 
of the radical ones, have shown that, as to prevalent 
position, the popular belief has a certain foundation in fact. 
The lines in ‘Evangeline’ * were inspired by a personal 
communication made by Gen. Alvord to the poet Long- 
fellow. 
“Since the leaves tend to assume a position in which 
the two faces are about equally illuminated by the sun, it 
might be suspected that their anatomical structure was 
conformed to this position. This has been confirmed, first 
by Mr. Edward Burgess, who, when a pupil of mine, 
observed that the stomata were about equally abundant on 
the two faces of the leaf; and next by Mr. Arthur, of Iowa, 
who has recently published in Prof, Bersey’s Introduction 
to Botany, a figure of a section of a leaf, showing that the 
arrangement of the ‘ palisade cells’ of the upper and lower 
strata is nearly the same. The leaves always maintain a 
vertical position, except when overborne by their weight. 
_ As to their orientation, not only is this rather vague in the 
cultivated plant, but subject to one singular anomaly, 
which may be commended to Mr. Darwin’s attention, I 
have several times met with a leaf abruptly and permanently 
twisted to a right angle in the middle ; 80 that, while the 
- lobes of the basal half pointed Say east and west, those of 
the apical half pointed north and south.” 
* Though, no doubt, familiar to many of my readers, these lines will well bear 
repetition here :— 
“ Look at this delicate plant that lifts its head from the meadow, 
See how its leaves are turned north, as true as the magnet ; 
This is the compass flower, that the finger of God has planted 
Here in the houseless wild, to direct the traveller’s journey 
Over the sea-like, athless, limitles. te of the d 
Such in the soul A gone is faith,” Ss waste of the desert. 
I cannot congratulate the poet on the fidelity of the description of the plant asa | 
“ delicate” one. take 
