See Also: Floral clock

Floral clock

A floral clock or flower clock is a large decorative clock set into a flower bed in a park or other public recreation area.The floral clock was a form of carpet bedding set onto an operational clock-face, invented in 1903 by John McHattie of Edinburgh Parks in Princes Street Gardens, Edinburgh and...

Linnaeus' flower clock was a garden plan hypothesized by Carolus Linnaeus

Carolus Linnaeus

Carl Linnaeus , also known after his ennoblement as , was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature. He is known as the father of modern taxonomy, and is also considered one of the fathers of modern ecology...

 that would take advantage of several plants that open or close their flowers at particular times of the day to accurately predict the time. He called it specifically the Horologium Florae (lit. "flower clock"), and proposed the concept in the 1751 publication Philosophia Botanica

Philosophia Botanica

Philosophia Botanica was published by the Swedish naturalist and physician Carolus Linnaeus who greatly influenced the development of botanical taxonomy and systematics in the 18th and 19th centuries. It is "the first textbook of descriptive systematic botany and botanical Latin"...

. He may never have planted such a garden, but the idea was attempted by several botanical garden

Botanical garden

A botanical garden The terms botanic and botanical, and garden or gardens are used more-or-less interchangeably, although the word botanic is generally reserved for the earlier, more traditional gardens. is a well-tended area displaying a wide range of plants labelled with their botanical names...

s in the early 19th century, with mixed success. Many plants exhibit a strong circadian rhythm

Circadian rhythm

A circadian rhythm, popularly referred to as body clock, is an endogenously driven , roughly 24-hour cycle in biochemical, physiological, or behavioural processes. Circadian rhythms have been widely observed in plants, animals, fungi and cyanobacteria...

, and a few have been observed to open at quite a regular time, but the accuracy of such a clock is diminished because flowering time is affected by weather and seasonal effects. The flowering times recorded by Linnaeus are also subject to differences in daylight due to latitude

Latitude

In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...

: his measurements are based on flowering times in Uppsala

Uppsala

- Economy :Today Uppsala is well established in medical research and recognized for its leading position in biotechnology.*Abbott Medical Optics *GE Healthcare*Pfizer *Phadia, an offshoot of Pharmacia*Fresenius*Q-Med...

, where he taught and had received his university education.

The plants suggested for use by Linnaeus are given in a table below, ordered by recorded time. A "-" signifies that data is missing.

Botanical name	Common name	Opening time	Closing time
Tragopogon pratensis	Goat's-Beard	3 a.m.	-
Leontodon hispidum L.	Rough Hawkbit	by 4 a.m.	-
Helminthotheca echioides (L.) Holub	Bristly ox-tongue	4-5 a.m.
Cichorium intybus L.	Chicory	4-5 a.m.	-
Crepis tectorum Crepis tectorum The Narrowleaf Hawksbeard, Crepis tectorum, is a annual or winter annual plant ranging from 30-100cm in height. It is an invasive species and during maturity it has one main stem, which is branched, hairless, and leafy. The leaves are arranged in an alternate manner and are less than 0.5 inches...  L.	Hawk's Beard	4-5 a.m.	-
Reichardia tingitana (L.) Roth	-	by 6 a.m.	10 a.m.
Sonchus oleraceus Sow thistle Sow thistle is the common name of two related genera of thistle-like flowering plants in the plant family Asteraceae:Also known as "Puha" by New Zealand Maori.*Cicerbita*Sonchussow thistle is a flower it's is from newzaeland....  L.	Sow thistle	5 a.m.	12 p.m.
Taraxacum officinale Taraxacum officinale Taraxacum officinale, the common dandelion , is a herbaceous perennial plant of the family Asteraceae . It can be found growing in temperate regions of the world, in lawns, on roadsides, on disturbed banks and shores of water ways, and other areas with moist soils. T...  Weber	Dandelion	5 a.m.	8-9 a.m.
Crepis alpina L.	Hawk's beard	5 a.m.	11 a.m.
Tragopogon hybridus L.	Goat's beard	5 a.m.	11 a.m.
Rhagadiolus edulis Gaertner	-	5 a.m.	10 a.m.
Lapsana chondrilloides L.	-	5 a.m.	-
Convolvulus tricolor Convolvulus tricolor Convolvulus tricolor , is a species of morning glory known by the common name Dwarf Morning Glory.- Description :It is a short to medium annual plant with solitary long-stalked flowers. The flower is a tri-coloured funnel-shaped bloom about three centimeters wide, blue with white and a yellow centre...  L.	Bindweed, Morning Glory	5 a.m.	-
Hypochaeris maculata L.	Spotted cat's ear	6 a.m.	4-5 p.m.
Hieracium umbellatum L.	Hawkweed	6 a.m.	5 p.m.
Hieracium murorum L.	Hawkweed	6 a.m.	2 p.m.
Crepis rubra L.	-	6 a.m.	1-2 p.m.
Sonchus arvensis Sonchus arvensis Sonchus arvensis is a medicinal plant. It is an invasive species in the Great Lakes region and was first sited in 1865.-External links:** Photos, Drawings, Text...  L.	Field milk-thistle	6 a.m.	-
Sonchus palustris L.	Marsh Sow-Thistle	by 7 a.m.	2 p.m.
Leontodon autumnale L.	Hawkweed	7 a.m.	3 p.m.
Hieracium sabaudum Hieracium sabaudum Hieracium sabaudum, also known as New England Hawkweed, is a species in the Asteraceae.- Common names :...  L.	Hawkweed	7 a.m.	1-2 p.m.
Cicerbita alpina Cicerbita alpina Cicerbita alpina or Alpine Blue-sow-thistle is a perennial herbaceous plant species belonging to the genus Cicerbita of the Asteraceae family.-Description:...  (L.) Wallr.	Blue sow-thistle	7 a.m.	12 p.m.
Lactuca sativa L.	Garden Lettuce	7 a.m.	10 a.m
Calendula pluvialis L.	-	7 a.m.	3-4 p.m.
Nymphaea alba Nymphaea alba Nymphaea alba, also known as the European White Waterlily, White Lotus, or Nenuphar, is an aquatic flowering plant of the family Nymphaeaceae....  L.	White Waterlily	7 a.m.	5 p.m.
Anthericum ramosum Anthericum ramosum Anthericum ramosum is a herbaceous perennial plant with a rhizome. The genus Anthericum is currently placed in the family Asparagaceae, subfamily Agavoideae. It was formerly placed in its own family, Anthericeae, and before that in the Liliaceae....  L.	St. Bernard's Lily	7 a.m.	-
Hypochaeris achyrophorus L.	-	7-8 a.m.	2 p.m.
Hedypnois rhagadioloides (L.) Schmidt subsp. cretica (L.) Hayck	-	7-8 a.m.	2 p.m.
Trichodiadema babrata (L.) Schwartes	-	7-8 a.m.	2 p.m.
Hieracium pilosella L.	Mouse-ear Hawkweed	8 a.m.	-
Anagallis arvensis L.	Scarlet pimpernell	8 a.m.	-
Petrorhagia prolifera (L.) Ball & Heywood	Proliferous Pink	8 a.m.	1 p.m.
Hypochaeris glabra Hypochaeris glabra Hypochaeris glabra is a species of flowering plant in the daisy family known by the common name smooth cat's ear. It is native to Eurasia and North Africa but it can be found on other continents where it is an introduced species and a widespread weed. This is an annual herb growing a small taproot,...  L.	Smooth cat's-ear	9 a.m.	1 p.m.
Malva caroliniana L.	-	9-10 a.m.	1 p.m.
Spergularia rubra Spergularia rubra Spergularia rubra, the red sand spurrey or red sandspurry, is a plant species in the pink family. It is native to Europe and Asia, and it is present on other continents, including North and South America and Australia, as an introduced species and in many areas a common weed. It grows in a wide...  (L.) J. & C. Presl	Sand spurrey	9-10 a.m.	2-3 p.m.
Mesembryanthemum crystallinum Mesembryanthemum crystallinum Mesembryanthemum crystallinum is a prostrate succulent plant that is native to Africa, Western Asia and Europe. The plant is covered with large, glistening bladder cells, reflected in its common names of Common Ice Plant, Crystalline Iceplant or Iceplant.-Uses:Its leaves are edible, as with some...	Ice-Plant	9-10 a.m.	3-4 p.m.
Cryophytum nodiflorum (L.) L. Bol.	Ice-Plant	10-11 a.m	3 p.m.
Calendula officinalis Calendula officinalis Calendula officinalis is a plant in the genus Calendula , in the family Asteraceae. It is probably native to southern Europe though its long history of cultivation makes its precise origin unknown, and may possibly be of garden origin...  L.	Pot marigold	-	3 p.m.
Hieracium aurantiacum	Hawkweed	-	3-4 p.m.
Anthericium ramosum L. (syn. Anthericum album)	-	-	3-4 p.m.
Alyssum alyssoides Alyssum alyssoides Alyssum alyssoides is a species of flowering plant in the mustard family known by several common names, including pale madwort and yellow alyssum...  L.	-	-	4 p.m.
Papaver nudicaule L.	Iceland poppy	-	7 p.m.
Hemerocallis lilioasphodelus Hemerocallis lilioasphodelus Hemerocallis lilioasphodelus, is a plant of the genus Hemerocallis. It is found across China, in Europe in N.E...  L.	Day-lily	-	7-8 p.m.

Such a floral "clock" is described by Andrew Marvell

Andrew Marvell

Andrew Marvell was an English metaphysical poet, Parliamentarian, and the son of a Church of England clergyman . As a metaphysical poet, he is associated with John Donne and George Herbert...

, in "The Garden" (1678):

How well the skilful gardener drew

Of flow'rs and herbs this dial new;

Where from above the milder sun

Does through a fragrant zodiac run;

And, as it works, th' industrious bee

Computes its time as well as we.

How could such sweet and wholesome hours

Be reckoned but with herbs and flow'rs!

External links

• Online text of Philosophia Botanica