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Lotus jacobaeus. Oct 14 Pulvinus development of

In the very young cotyledons about 2 or to 2 1/2 mm long, the impression given is that there is no differentiated zone of smaller cells. The impression is given that all the epidermis cells are of the same size because there is not a region of differently shaped epidermis cells as in the older ones. But the epidermis cells do get bigger as you look farther down the stalk. Near the leaf the cells they are 5.015mm divisions of micrometer*, the biggest ones lower down are 10° .030mm. I Examined 2 plants which were seen to sleep well & had had raise their cotyledons considerably & had cotyledons 4mm long. The part of epidermis which has not devel where the pulvinus is not develop The pulvinus cells are on the average 7.021mm in length & retain their original form. The rest of the epidermis has developed c conical projections so that it looks so ↓[sketch] pulvinus

& the cells are about 20.060mm in length.

[in margin:] Frank *HK viii

Cut a good section of this leaf & found that the parenchyma and cells of the pulvinus differ from the ordinary parenchyma in size, & in roughly the same proportions as the epidermis cells do— That is to say if one takes a middle layer

(F. see over)

2

of cells between the epidermis & the fibro vascular bundles. The epidermis cells of cotyledon itself are in this specimen about 5.034 or 6°.040mm (HKV2)? whereas in the young cotyledons they are about 4.27mm but the measurements on the older specimen are rather doubtful.

There are chlorophyll grains in the parenchyma of a young cotyledon close to lamina, so there must be a retrogression or reabsorption of chlorophyll.

The pulvinus seem formed by growth soon ceasing

[calculations not transcribed]