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This page was last updated on 5^th February 2003
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Introduction

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Mid.	1am	2am	3am	4am	5am	6am	7am	8am	9am	10am	11am

Noon	1pm	2pm	3pm	4pm	5pm	6pm	7pm	8pm	9pm	10pm	11pm

The Javascript clock above is entirely my own work but is based on the work of Carl Linnaeus, according to whom it should be possible to tell the time of day by looking at which flowers are starting to open or close. I doubt he ever used this method though as a number of his selected flowers are either extremely rare or restricted to remote sites such as mountain tops. You would also have to be an experienced naturalist as most of them are almost identical yellow weeds.

The three images on the clock show the flower which should have opened/closed an hour ago, the flower which should be opening/closing now and the flower which should be opening/closing in an hour's time.

The time is updated every second and the flowers will shift round on the hour. The complete list of flowers used is shown above.

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Acknowledgements

The text below is adapted from a webpage by Arne Sjoeqvist of the Swedish Environmental Protection Agency.

Most flower images adapted from 'Complete British Wildlife' by Paul Sterry, published by Collins. ISBN 0-00-220071-6

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The origins of the Flower Clock

Carl von Linne' (Latin name: Carl (Carolus) Linnaeus) made observations of when different flowers opened and closed during the day. His findings were published in Philosophica botanica in 1751 at which time he had already been professor for some years at the Uppsala University.

He descibed three groups of flowers:

Meteorici, flowers which change their opening and closing times according to weather conditions.

Tropici, flowers which change their times for opening and closing with the length of the day.

Aequinoctales, flowers which have fixed times for opening and closing.

Only Aequinoctales are suiTABLE if you want to use flowers to see what time it is. The three left columns in the TABLE below is the list of "Horologium flore" published in Philosophica botanica (1751).

Linnaeus probably never planted a 'flower clock'. Instead it is assumed that he made his accurate observations on plants growing at various localities (including various localities in the botanical garden).

Linnaeus' son, Carl Linnaeus fil., started to write a thesis on HOROLOGIUM PLANTARUM. His thesis was never completed and it only mentions a few examples of 'AEquinoctales' and does not contain a description of a flower clock as such.

To make a flower clock you must must select and test suiTABLE flowers from the list. You should be prepared to replace species when they cease flowering. I have been in contact with a retired gardener of the Linnean garden, Uppsala and he has successfully tested the plants marked with an asterisk (*) and used them to make a public flower clock.

Please observe that the times below follow solar time and that they are not adjusted to summer time.

Horologium Flore ex sequenti tabula
formandum, postquam meteorici & Tropici
flores excludi sunt, de quibus alibi.

Opens	Closes	Old Name	Modern Name	Common Name
3	-	Tragopogon luteum	Tragopogon pratensis L. *	Goatsbeard
4	-	Leontodon Taraxonoid	Leontodon hispidus L. *	Rough Hawkbit
4/5	-	Picris magna	Picris hieracioides L.	Hawkweed Oxtongue
4/5	-	Cichoreum scanense	Cichorium intybus L. *	Chicory
4/5	-	Crepis tectorum	Crepis tectorum L.	Smooth Hawksbeard
5	-	Sonchus laevis	Sonchus oleraceus L.	Smooth Sow-thistle
5	-	Leontodon Taraxacum	Taraxacum officinale	Dandelion
5	-	Crepis alpina	Crepis alpina L.	None
5	-	Tragopagon Columnae	Geropogon glabrum L.	Old Man's Beard
5	-	Lapsana Ragadiolus	Ragadiolus edulis Gaertn. (R. stellatus (L.) Gaertner)	None
5	-	Lapsana glutinosa	Crepis pulchra L.	SMALLflower Hawksbeard
5	-	Convolvulus rectus	Convolvulus tricolor L.	Dwarf Morning Glory
6	-	Scorzonera tingitana	Reichardia tingitana (L.) Roth (Picridium tingitanum L.)	False Sow-thistle
6	-	Hypochoeris pratensis	Hypochoeris pratensis L.
6	-	Hieracium fruticosum	Hieracium umbellatum L.	Northern Hawkweed
6/7	-	Pulmonaria	Hieracium murorum L.	Golden Lungwort
6/7	-	Crepis rubra	Crepis rubra L. *	Red Hawksbeard
6/7	-	Sonchus repens	Sonchus arvensis L.	Corn Sow-thistle
7	-	Sonchus belgicus	Sonchus palustris L.	N/A
7	-	Leontodon Chondrilloides	Leontodon autumnalis L.	N/A
7	-	Hieracium latifolium	Hieracium sabaudum L.	N/A
7	-	Sonchus lapponicus	Lactua alpina A. Gray (Mulgedium alpinum (L.) Cass.)	N/A
7	-	Lactuca sativa	Lactuca sativa L.	N/A
7	-	Calendula africana	Calendula pluvialis L.	N/A
7	-	Nymphaea alba	Nymphaea alba L.	N/A
7	-	Anthericum album	Anthericium ramosum L.	N/A
8	-	Hypochoeris hispida	Hypochoeris maculata L.	N/A
8	-	Lapsana Rhagadioloides	Phaecasium lampsanoides Cass.	N/A
8	-	Mesembryant. barbat.	Mesembryanthemum barbatum L.	N/A
-	8/9	Leontodon Taraxacum	Taraxacum vulgare (officinalis)	N/A
9	-	Hieracium Pilosella	Hieracium pilosella L. *	N/A
9	-	Anagallis rubra	Anagallis arvensis (red flowers)*	Scarlet Pimpernel
9	-	Dianthus prolifer	Petrorhagia prolifera (L.) P.W. Ball & Heywood (Tunica prolifera (L.))*	N/A
9	-	Hypochoeris Chodrilloid.	Hypochoeris radicata L.	N/A
10	-	Malva helvola	Malva caroliniana L. *	N/A
10	-	Arenaria purpurea	Spergularia rubra (L.) J. & C. Presl	N/A
10	-	Mesembr. crystallinum.	Mesembryanthemum crystallinum L.	N/A
10	-	Lapsana. glutinosa	Crepis pulchra L.	N/A
10	-	Lactuca sativa	Lactuca sativa L.	N/A
10	-	Scorzonera tingitana	Reichardia tingitana L. Roth	N/A
10/11	-		Mesembr, neapolit.	N/A
11	-	Crepis alpina	Crepis alpina L.	N/A
-	11	Tragopogon Columnae	Geropogon glabrum L.	N/A
-	12	Sonchus laevis	Sonchus oleraceus L.	Smooth Sow Thistle
-	12	Sonchus lapoponicus	Mulgedium alpinum (L.) Cass.	N/A
-	1	Hypochaeris Chondrill.	Hypochoeris radicata L.	N/A
-	1	Malva helvula	Malva caroliniana L.	N/A
-	1	Dianthus prolifer	Petrorhagia prolifera (L.) Ball & Heywood *	N/A
-	2	Hieracium latifolium	Hieracium sabaudum L.	N/A
-	2	Crepis rubra	Crepis rubra L. *	N/A
-	2	Hypochoeris hispida	Hypochoeris maculata L. *	N/A
-	2	Hieracium Pulmonaria	Hieracium murorum L.	N/A
-	2	Sonchus belgicus	Sonchus palustris L.	N/A
-	2	Lapsana Rhagadioloid.	Rhagadiolus edulis Gaertn.	N/A
-	2	Mesembr. barbatum	Mesembryanthemum barbatum L.	N/A
-	3	Arenaria purpurea	Spergularia rubra (L.) J. et C.	N/A
-	3	Leontodon Chondrilloides	Leontodon autumnale L.	N/A
-	3	Calendula arvensis	Calendula arvensis L.*	Field marigold
-	3	Mesembr. neapolit.	n/a	N/A
-	3	Mesembr. linguiform.	n/a	N/A
-	4	Hieracium rubrum	n/a	N/A
-	4	Mesembr. crystallin.	Mesembryanthemum crystallinum L.	Iceplant
-	4	Calendula africana	Calendula pluvialis	African marigold
-	4	Anthericum album	Anthericium ramosum L.	N/A
-	4	Alyssum Alyssoides	Alyssum alyssoides (L. L.	Pale alyssum
-	5	Hypochoeris pratensis	Hypochoeris pratensis L.	N/A
-	5	Hieracium fruticosum	Hieracium umbellatum L.	Bushy hawkweed
-	5	Nymphaea alba	Nymphaea alba L.	Water lily
-	7	Papaver nudicaule	Papaver nudicaule *	Icelandic poppy
-	8	Hemerocallis fulva	Hemerocallis fulva*	Day lily