Darwin Correspondence Project

June 25th 1878. The short petioles of the Cots. of Cassia are enlarged, transversely wrinkled & formed of tissues appearing different from that of lamina & Hypocotyl.— How is Oxalis valdiviana & rosea or floribunda?? I neglected to observe with Cassia whether when Cots. Horizontal upper surface of petiole is transversely wrinkled.—

I have looked at Cots. of Oxalis floribunda & there seems to be a semicircular pale-coloured pulvinus on upper surface formed of smaller cells; but it tired me too much to look carefully.— Now on O. corniculata the cots of which raise only 45o I can see no pulvinus.— This very important showing that pulvinus developed in same genus.