Gravity is the word—­not solemnity as towards evening, nor menace as at night.  The daylight trees of July are signs of common beauty, common freshness, and a mystery familiar and abiding as night and day.  In childhood we all have a more exalted sense of dawn and summer sunrise than we ever fully retain or quite recover; and also a far higher sensibility for April and April evenings—­a heartache for them, which in riper years is gradually and irretrievably consoled.

But, on the other hand, childhood has so quickly learned to find daily things tedious, and familiar things importunate, that it has no great delight in the mere middle of the day, and feels weariness of the summer that has ceased to change visibly.  The poetry of mere day and of late summer becomes perceptible to mature eyes that have long ceased to be sated, have taken leave of weariness, and cannot now find anything in nature too familiar; eyes which have, indeed, lost sight of the further awe of midsummer daybreak, and no longer see so much of the past in April twilight as they saw when they had no past; but which look freshly at the dailiness of green summer, of early afternoon, of every sky of any form that comes to pass, and of the darkened elms.

Not unbeloved is this serious tree, the elm, with its leaf sitting close, unthrilled.  Its stature gives it a dark gold head when it looks alone to a late sun.  But if one could go by all the woods, across all the old forests that are now meadowlands set with trees, and could walk a county gathering trees of a single kind in the mind, as one walks a garden collecting flowers of a single kind in the hand, would not the harvest be a harvest of poplars?  A veritable passion for poplars is a most intelligible passion.  The eyes do gather them, far and near, on a whole day’s journey.  Not one is unperceived, even though great timber should be passed, and hill-sides dense and deep with trees.  The fancy makes a poplar day of it.  Immediately the country looks alive with signals; for the poplars everywhere reply to the glance.  The woods may be all various, but the poplars are separate.

All their many kinds (and aspens, their kin, must be counted with them) shake themselves perpetually free of the motionless forest.  It is easy to gather them.  Glances sent into the far distance pay them a flash of recognition of their gentle flashes; and as you journey you are suddenly aware of them close by.  Light and the breezes are as quick as the eyes of a poplar-lover to find the willing tree that dances to be seen.

No lurking for them, no reluctance.  One could never make for oneself an oak day so well.  The oaks would wait to be found, and many would be missed from the gathering.  But the poplars are alert enough for a traveller by express; they have an alarum aloft, and do not sleep.  From within some little grove of other trees a single poplar makes a slight sign; or a long row of poplars suddenly sweep the wind.  They are salient everywhere, and full of replies.  They are as fresh as streams.