My dear Gray

It was very good of you to send me M^r. Rattan’s letter which has interested me extremely.¹ I suppose that I may give some of his statements. It seems almost certain that the protection of the plumule from frost has determined the curious mode of germination; & this agrees well with the drawing down in winter of so many seedlings by the contraction of their radicles. But I still think the protection of the enlarged roots from being devoured is probably a secondary advantage thus gained.² The “crocks” explain the behaviour in your first case.³

What a curious fact of M^r. Rattan’s,—that of the confluent petioles growing out horizontally without coming into contact with the bottom of the shallow box. From what I have observed with other seedlings I believe I understand the cause, but it is too long a story.⁴ I wish I had a score of germinating seeds to experimentise on.—

Very many thanks for P. Card about roots of Ipomœa leptophylla: I have tried in vain to get seeds of I. pandurata from Kew.⁵

Ever yours very truly | Ch. Darwin

M^r Rattan seems to be a real good observer, & that is a rare species of animal.—