Using Kent's Book and Supplements

However useful Kent may be to the experienced botanist it can be a nightmare of a reference book for the beginner. Many of us began an interest in wild flowers through getting to know the common names of what we saw around us. Later we began that difficult journey into Latin names, marvelling at the different pronunciations which experienced botanists spouted at meetings.

Later one noted that many serious books on wild plants would put the ferns and horsetails near the beginning, grasses, orchids and lilies near the end and clovers somewhere in the middle. This order is an accepted convention amongst botanists but unless you have memorised the families and the order in which they should be arranged, you need an alphabetical index to find every plant.

Kent uses no common names and the list is in the conventional order of families not in alphabetical order. Each plant is allocated a unique Kent reference.

Examples of the Kent references are here in the column marked Kent ref.

Systematic Names Common Name In Kent? Type Kent ref. Status Authority Record No.
Echium vulgare Viper's-bugloss Page 29 A1 116--2--1 N L. 0920000670
Epipactis dunensis Dune Helleborine Yes S3 A1 162--3--dun N (T. & T.A. Stephenson) Godfery  
Gypsophila paniculata Baby's-breath Yes S1 A1 46--GYP--pan Ne L. 0920005408
Geum rivale x urbanum = G. x intermedium Hybrid Avens Yes A1 75--13--1 x 2 N Ehrh. 0920000923
Geranium phaeum x reflexum = G. x monacense Munich Crane's-bill Yes A1 103--1--23 x ref Ne Harz 0920007389
Phyllitis scolopendrium x Asplenium obovatum = X Asplenophyllitis microdon   Yes A1 15--1 x 2--1 x 3   (T. Moore) Alston *
Bidens pilosa Black-jack Stace A2 135--81--pil Ca L. 0920007972
Taraxacum officinale agg.   Aggregate AK 135--25--- N    
Dactylis glomerata subsp. glomerata   Other AT 153--19--1--a      

Long established Kent species in an existing Kent genus

Echium vulgare (Viper's bugloss) is listed as a Kent species and is also a WFS diary species on page 29. It has the Kent reference 116--2--1. In the supplements and on the BSBI list this would appear as 116/2/1.

The 116 means that it is a member of the 116th family starting from the beginning of the book (Boraginaceae).

The 2 refers to the genus Echium which is the second genus listed in the Boraginaceae family.

The 1 means Echium vulgare is the first species listed in the Echium genus.

To look up a plant in the Kent list or in one of the Supplements you first use the Family number which for most of the book is at the top of the page. After that you advance to the genus number and from there to the species. Subspecies are added by using a, b, c etc. as a fourth designation as in Dactylis glomerata subsp glomerata which has the reference 153--19--1--a.

New Kent species in an existing genus

Epipactis dunensis (Dune Helleborine) 162--3--dun is not listed in the original Kent book as it had not been recognised as a separate species in the Epipactis genus at that time. There is therefore no species number for this plant and the convention is to use three letters of the species name, in this case dun.

New Kent species in an new Kent genus

Gypsophila paniculata (Baby's Breath) 46--GYP--pan was not in the original Kent book either as the genus Gypsophila or as the species paniculata but has been added to the list in supplement 1. Both genus and species must therefore be allocated letters. The convention is to allocate the genus three capital letters if no Kent number is available. The plant is not new to science and is known to be a member of the Caryophyllacaea family number 46. The genus has no number and so is allocated GYP and the species also has no number so becomes pan

Non Kent species

Because the Kent referencing system follows simple rules, any plant can be give a Kent reference. The casual alien Bidens pilosa (Black-jack) has been given a Kent reference even though it doesn't appear in the book or any of the supplements. It is known to be both a member of the Asteraceae family and the Bidens genus but can have no species number. The reference is therefore: 135--81--pil. This might be obvious to experienced taxonomists but is a source of confusion because well over 3,000 plants have Kent references in these tables but will never be on the Kent list an so can't be included in the WFS diary under our current rules.

Hybrids between listed Kent species

Geum rivale (Water Avens) 75--13--1 and Geum urbanum (Wood Avens) 75--13--2 often hybridise to produce an plant intermediate in appearance which has been given a hybrid name: Geum x intermedium.

The full entry lists both parents if they are known and the hybrid name if one is given. The Kent reference number which ends with both species numbers linked by a multiplication sign:

Geum urbanum x Geum rivale = G. x intermedium 75--13--1 x 2

Hybrids between species not listed in Kent

Geranium reflexum (Reflexed Crane's-bill) 103--1--ref which is not a Kent species hybridises with Geranium phaeum (Dusky Crane's-bill) which is in the original Kent book as the 23rd listed Geranium species: 103--1--23. The hybrid is known as Geranium x monacense and also has the common name of Munich Crane's-bill.

The entry for this was in the original Kent book as:

Geranium phaeum x Geranium reflexum = G. x monacense 103--1--23 x ref

Aggregates

Dandelions are so hard to identify that many botanists will record them as the aggregate. Taraxacum officinale agg. really means "Some unknown species of Dandelion". So the family Asteraceae is known and the genus Taraxacum is known but the species hasn't been determined so the Kent number can have no species reference. Hence Taraxacum officinale agg. 135--25---. In the WFS dairy Taraxacum officinale agg. has been shortened to Taraxacum agg. (Page 91) but neither is a member of Kent's list either in the original book or in the supplements.

Intergeneric Hybrids

Rarely species which are not member of the same genus can hybridise producing an Inter specific hybrid. This poses a challenge for both Taxonomic nomenclature and for Kent's referencing system. Two well known ferns which hybridise are:

Phyllitis scolopendrium (Hart's-tongue Fern) 15--1--1

and

Asplenium obovatum (Lanceolate Spleenwort) 15--2--3

They both belong to the same Aspleniaceae family but to different genera so the name and reference become:

Phyllitis scolopendrium x Asplenium obovatum = X Asplenophyllitis microdon 15--1 x 2--1 x 3

Here the family is number 15, the genus 1 x 2 and the species is 1 x 3. Note that a capital X is used when intergeneric hybrids are named. This is actually one case where it is easier to look up a plant using the Kent system since it isn't obvious where in an alphabetic list such a hybrid might occur. In these lists it occurs under list P because the name begins with Phyllitis.

This intergeneric hybridisation occurs between Dactylorhiza species (Marsh Orchids) and Coeloglossum viride (Frog Orchid) too but since it is now believed that Coeloglossum viride should really be Dactylorhiza viride that would change the names and references of all the hybrids too. No wonder Clive Stace thinks there should be a new book rather than any more supplements.

Peter Llewellyn 1st November 2010

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