Summary

Sleep in Porlieria studied.

Oats begin germinating.

Summary

Chlorophyll development in oat seedling.

Lists the sleeping plants he has seen.

Julius Sachs thinks Hugo de Vries has not cleared up everything [about climbing plants]. But Sachs has not worked on the mechanical problem.

Summary

Asks for list of families of sleeping plants. Believes sleep is merely modified circumnutation at a particular time of day.

Porlieria has had no water for some time but shows no sign of flagging.

Describes the response of Thalia flowers to touch.

Summary

More sleepers from green-house.

Julius Sachs’s view of climbing plants: he distinguishes between nutation to find a support and growth after support is found.

Summary

Discusses sleep movements of Porlieria.

Has read an abstract of Julius Wiesner on heliotropism and geotropism ["Die heliotropischen Erscheinungen im Pflanzenreiche", Anz. Kais. Akad. Wiss. Wien 15 (1878): 137–40] which seems important but is puzzling.

Gives details of his observations on climbing plants with reference to comments by Julius Sachs.

Summary

Has offered Carl Semper the writing machine.

Speculates on the mechanism of movement in plants and their reception of and response to stimuli.

Summary

Horace Darwin suggests FD water the Porlieria copiously to see whether it will keep awake all day.

[Possibly P.S. to 11620.]

Summary

Has been investigating nutational movements of climbing plants; comments on the opinions of Julius von Wiesner and Julius Sachs. Remarks on the sleep movements of certain plants and the mechanism of tendril curvature. Is experimenting with Porlieria.

Has visited K. G. Semper’s laboratory.

Summary

Notes Julius Sachs’s opinion on the heliotropism of moulds: he can see no use in the response.

C. E. Stahl is working on swarm spores which can be made both helio- and apheliotropic.

Sachs has told him that some ferns sleep, and he suspects that some grasses may move.

Sachs also feels they may be working at bloom from a wrong point of view and suggests leaves may need to keep dry in order to keep their stomata open.

Summary

Is forwarding the writing machine to Carl Semper.

Is glad FD has taken up his old friends, the twiners.

Hopes to get heliotropic aerial roots from J. D. Hooker. Asks FD to find out whether any moulds or roots are apheliotropic. Is puzzled by heliotropism in subterranean roots.

Summary

Experiments on effects of removing "bloom" from leaves and fruit.

Summary

Comments on function of bloom.

Describes the effect of water shortage on sleep movements in Porlieria.

Summary

Sachs jumps to the conclusion twiners and tendrils are similar from the Menispermum that twined without a stick. Akebia grows down a stick; not only the free end is involved.

Sleeping plants.

Summary

Is pleased FD’s climbing work goes well.

Thanks him for information on heliotropism.

Discusses sleep movements

and his observations on the sensitivity of radicle tips.

Summary

Instructs FD to plant some Oxalis seeds.

Wishes to trace the movement of an old cotyledon. Asks him to examine and compare the pulvinus of a species which moves its cotyledon greatly with one of a species that moves it only moderately.

Are the tendrils ready for heliotropic experiment yet?

Summary

Instructions to sow some seeds

and suggestions for experiment on effects of removal of bloom.

Likes Hugo de Vries very much; has hardly ever seen so modest a man.

Summary

Asks FD to reply to a letter [11653a] requesting a list of CD’s books.

Summary

Observations of leaf movement at Würzburg Botanic Garden.

Summary

Julius von Sachs’s views on stomata seem largely correct, but CD cannot understand how leaves can survive submerged for such long periods.

Has been observing Drosera and concludes that none of the movement of the tentacles is caused by growth.

Suggests observations to show role of pulvinus in leaf movement.

Summary

He has been working hard at Kew for two days.