My dear Gray

This is a P.S. to yesterday’s letter to say that the drawing at p. 21 of your text Book w^d. represent perfectly all that I have seen, supposing that a line were drawn, representing the surface of the soil, $\frac{1}{2}$ inch above the seed, assuming that the seed had been sown at $\frac{1}{2}$ inch depth.—² You may perhaps like to hear that the first true leaves break out through a split at base of confluent petioles of Delphinium nudicaule presicely as in Megarrhiza.³ The swelling of the plumules bursts the tube, & then the bowing downwards of the tip of the plumules of Megarrhiza, forces it laterally out of the tube. The tip is at first straight.—

This bowing down of the tip is a very common or rather universal movement with seedlings, but here it plays a new part.

Ever yours | C. Darwin