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Foliage Development in One Plant

Photographs at Holloway Garden in 2000

On February 9, 2000 I completed a study of "Color as an Aid to the Identification of Poison-Oak." The study concluded: "Xanthophils with a reddish purple hue are an easily learned cue to the presence of poison-oak . . . from February to mid-march."

From Christmas through January the poison-oak was dormant (see also The Seasonal Appearance of Poison-Oak: An Overview). By late March the foliage was green, and the poison-oak blended in with the other plants; quick and distant identification was no longer possible.

In order to promote the use of color for identification I took the following pictures:

January

February

12

13

The breaking of dormancy is a very distinct event. Overnight a few of the tiny, hairy, silvery, winter buds swell and crack open, revealing a glimpse of their red contents and giving the whole plant a distinctive reddish tinge. This occurred February 7 at Holloway Gardens and one day later in many other Montano de Oro locations.

February 18

Whole Plant
2

Crown Close-Up

Base Close-Up

3

4

There is more activity in the top of the plant; see Apical Dominance. However, the low leaves are larger and greener because they don't get as cold at night.


February 22

Whole Plant

5

Crown

Base

6
7

March 6

Whole Plant

9

Crown                      Base

10

 
11

 


March 15

Holloway 


March 21

8
The plant is now green, and is blooming abundantly!

 

All content copyright Dr. Curt Beebe. Please do not use without permission.