THE FLOWER CLOCK
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Carl von Linne' (Latin name: Carl (Carolus) Linnaeus) made observations
of when flowers open and close during the day. He published his
findings in Philosophica botanica in 1751. At that time Linnaeus had
already been professor for some years at the Uppsala University but it
was before he published his well-known works on systematics.
Linnaeus 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.
) ( More recent scientific names
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3. - Tragopogon luteum Tragopogon pratensis L. *
4. - Leontodon Taraxonoid. Leontodon hispidus L. *
4.5 - Picris magna Picris hieracioides L.
- - Cichoreum scanense Cichorium intybus L. *
- - Crepis tectorum Crepis tectorum L.
6. - Scorzonera tingitana Reichardia tingitana (L.) Roth
(Picridium tingitanum L.)
5. - Sonchus laevis Sonchus oleraceus L.
- - Leontodon Taraxacum Taraxacum officinale
- - Crepis alpina Crepis alpina L.
- - Tragopagon Columnae Geropogon glabrum L.
- - Lapsana Ragadiolus Rhagadiolus edulis Gaertn.
(R. stellatus (L.) Gaertner)
- - " glutinosa Crepis pulchra L.
- - Convolvulus rectus Convolvulus tricholor L.
6. - Hypochoeris pratensis Hypochoeris pratensis L.
- - Hieracium fruticosum Hieracium umbellatum L.
6.7. - Pulmonaria murorum L.
- - Crepis rubra Crepis rubra L. *
- - Sonchus repens Soncus arvensis L.
7. - " belgicus palustris L.
- - Leontodon Chondrilloides Leontodon autumnalis L.
- - Hieracium latifolium Hieracium sabaudum L.
- - Sonchus lapponicus Lactua alpina A. Gray (Mulgedium
alpinum (L.) Cass.)
- - Lactuca sativa Lactuca sativa L.
- - Calendula africana Calendula pluvialis L.
- - Nymphaea alba Nymphaea alba L.
- - Anthericum album Anthericium ramosum L.
8. - Hypochoeris hispida Hypochoeris maculata L.
- - Lapsana Rhagadioloides Phaecasium lampsanoides Cass.
- - Mesembryant. barbat. Mesembryanthemum barbatum L.
9. - Hieracium Pilosella Hieracium pilosella L. *
- - Anagallis rubra Anagallis arvensis (red flowers)*
- - Dianthus prolifer Petrorhagia prolifera (L.) P.W.
Ball & Heywood (Tunica prolifera
(L.))*
- 8.9. Leontodon Taraxacum Taraxacum vulgare (officinalis)
9. - Hypochoeris Chodrilloid. Hypochoeris radicata L.
10. - Malva helvola Malva caroliniana L. *
- - Arenaria purpurea Spergularia rubra (L.) J. & C. Presl
- - Mesembr. crystallinum. Mesembryanthemum crystallinum L.
10. - Lapsana. glutinosa Crepis pulchra L.
- - Lactuca sativa Lactuca sativa L.
- - Scorzonera tingitana Reichardia tingitana L. Roth
10.11.- Mesembr, neapolit.
- 11. Crepis alpina Crepis alpina L.
- - Tragopogon Columnae Geropogon glabrum L.
- 12. Sonchus laevis Sonchus oleraceus L.
- 12. " lapoponicus Mulgedium alpinum (L.) Cass.
- 1. Hypochaeris Chondrill. Hypochoeris radicata L.
- - Malva helvula Malva caroliniana L.
- - Dianthus prolifer Petrorhagia prolifera (L.) Ball
& Heywood *
- 2. Hieracium latifolium Hieracium sabaudum L.
- - Crepis rubra Crepis rubra L. *
- 2. Hypochoeris hispida Hypochoeris maculata L. *
- - Hieracium Pulmonaria Hieracium murorum L.
- - Sonchus belgicus Sonchus palustris L.
- - Lapsana Rhagadioloid. Rhagadiolus edulis Gaertn.
- - Mesembr. barbatum Mesembryanthemum barbatum L.
- 3. Arenaria purpurea Spergularia rubra (L.) J. et C.
- 3. Leontodon Chondrilloides Leontodon autumnale L.
- - Calendula arvensis Calendula arvensis L.*
- 3. Mesembr. neapolit.
- - " linguiform.
- 4. Hieracium rubrum
- - Mesembr. crystallin. Mesembryanthemum crystallinum L.
- - Calendula africana Calendula pluvialis
- - Anthericum album Anthericium ramosum L.
- - Alyssum Alyssoides Alyssum alyssoides (L. L.
- 5. Hypochoeris pratensis Hypochoeris pratensis L.
- 5. Hieracium fruticosum Hieracium umbellatum L.
- - Nymphaea alba Nymphaea alba L.
- 7. Papaver nudicaule Papaver nudicaule *
- 8. Hemerocallis fulva Hemerocallis fulva*
Regards,
Arne Sjoeqvist
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Arne Sjoeqvist
INFOTERRA/Sweden
Swedish Environmental Protection Agency
S-106 48 STOCKHOLM
ars@environ.se Tel:+46 8 6981273 Fax: +46 8 6981400
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