Arum Maculatum L. Author(S): F

Home , Arum maculatum

Arum Maculatum L. Author(s): F. A. Sowter Source: Journal of Ecology, Vol. 37, No. 1 (Jul., 1949), pp. 207-219 Published by: British Ecological Society Stable URL: http://www.jstor.org/stable/2256754 . Accessed: 11/08/2011 10:39

Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected].

British Ecological Society is collaborating with JSTOR to digitize, preserve and extend access to Journal of Ecology.

http://www.jstor.org [ 207 ]

ARUM L. L.C. (Ed. 11) No. 1924 Arum maculatum L..

F. A. SOWTER A robust,somewhat fleshy perennial, 15-40 cm., with 4-6 radical leaves springingfrom a stout whitishcorm. Leaf lamninahastate, with deflexedlobes, shining,with irregular black to purpleblotches or uniformlygreen; veins pinnately branched, sometimes whitish; petiole channelledabove, 10-20 cm. Flowers monoecious,protandrous, crowded on a

12 8o 8 6 4 2 o 2 4 . 30' 20 10 0 10 20 3'4

58/e 5

56 = 5

Presentbut not snign-11- ous t

10 ll 86ltbe iLongitude;t 4 ofGreenwich 2 OLgitdeEast2efGrftenw Fig. 1. Arummaculatum L. Vice-comitaldistribution in BritishIsles and (inset) distributionin Europe. verticalaxis prolongedas the purplishor yellowishclub-shaped spadix (5-6 x 0 5-0 7 cm.). Spathe cowl-shaped,tapering, convolute with overlapping edges at the base, open at the base ofthe spadix, shrivellingafter flowering, spotted or uniformlygreen, 10-25 cm. long. Inflorescenceaxis bearing(in orderfrom the base of the spadix downwards):(a) a zone of 30-40 deflexedhairs, 4-5 mm.long; (b) a zone ofc. 100 sessilepurplish red to yellowanthers, 208 Arummnaculatum 1-1 5 mm. long,dehiscing longitudinally, mostly arranged in pairs; (c) 30-50 pale yellow syncarpousunilocular ovaries, 3 mm.long, with short style and entirestigma; the highest row are sterileand have terminalfilamentous processes. Perianth and nectariesnone. Infructescencea bare spike of berries,scarlet when ripe, containing1-4 reticulated, globose seeds (6 x 5 mm.). Plants withspotted leaves (f. nmaculatum)and thosewith unspotted leaves (f. immacula- tum)grow together in similarhabitats. The varietytetrelii Corb. has a yellowspadix, but plants may be foundshowing intermediate spadix colours.The darkpatches on the leaves of the spotted formare due to a purple anthocyanin(Wheldale, 1916). Stahl (1896) suggestedthat the anthocyaninof this and othershade plants increasesthe absorption of heat by the leaves and thus promotestranspiration. Often the markingcorresponds with a prominentelevation or depressionand both may be foundon the same leaf. The frequencyand distributionof spottedand unspottedplants in Britainis extremely variable,but Pethybridge(1903) concludedthat in England, as in Ireland,spotted plants are much moreuncommon than unspotted. A count made by Phillips (1903) at Graign- managh,Ireland, showed a proportionof spotted to unspottedplants of 1: 500, but counts by the presentwriter in the Midlandsgave a proportionof 1: 4 88. Bromfield(1856) states that the unspottedplant is rarerin the north. A lowlandspecies of woods, hedgebanks and shadyplaces widelydistributed throughout England, Wales, Ireland and southernScotland. I. Geographicaland altitudinaldistribution. Recorded for all English vice-counties. Much plantinghas occurredin Scotland,but it extendsnorthwards as a native speciesto a lineapproximating the River Forth to Argyle.North of this limit it is generallyconsidered naturalized. It is doubtfullyrecorded for west Perthwith Clackmannan (87), mid-Perth (88), south Aberdeen (92), Banff(94), Moray (95) and Caithness (109). There are also recordsfrom east Perth (89) and Angus (90). In the latter vice-countyit grows in a shrubberyat Parkhillnear Arbroath,where it has probablybeen planted (U. K. Duncan). Campbell(1936) records it forNorth Uist ( 110) 'underwall, outside a garden'.It is abundant at FinlarigCastle, Killin, Perthshire (88), but not native (White,1898). Althoughnoted as 'doubtful'from Fife withKinross (85) (Comit.Fl.), it is recordedfrom eleven localities in this vice-county(Young, 1936). Recordedfor all Irish vice-counties,but it is generally rarerin the west than in the east (Ir. Top. Bot.), its north-westernlimit being reached in the Donegal Bay area (Bot. Irl.). In the ChannelIslands it occursin Jersey(Babington, 1839), Guernsey,Sark and Jethou. Absentfrom Alderney, Herm, Lihou and Crevichon (Marquand, 1901). Widely spread over southernand central Europe, northwardsto southernSweden (lat. 580 N.) (absent fromNorway), and eastwardsto Poland, the Car- pathians and the Caucasus, whereit is replacedby Arurnorientale. It is cited forTurkey (Cyb.Brit. Compendium);the Balkan Peninsulasouthwards to Peloponnesus;in Italy to the centreof the peninsula. Also in Spain and, accordingto Watson,crossing to Algeria (lat. 350 N.), bu-tBattandier & Trabut (1902) do not recordit forAlgeria and Tunis and say that A. italicumhas been recordedin the past as A. maculatum.Jahandiez & Maire (1931, 1934) say it is absentfrom Morocco, but mentionthat it has been recordedin error. Thus it seemsabsent from North Africa. Its frequencyis variable. In centraland western France it is oommon,widespread in Belgium and Holland, whilstin certain parts of Germanyit is quite absent (e.g. East Mecklenburgand Prussia) (Lebensg.1, iii, p. 33). In England ascends to 1350 ft. (411 m.) on ThornthwaiteScar, above Brough(Wilson, F. A. SOWTER 209 1938); 1200 ft. (365 m.) on Leck Fell, west Lanes; 1050 ft. (320 m.) in Derbyshire(West); 980 ft.(298 m.) in Teesdale; 750 ft. (228 m.) Buckden,Craven-in-Wharfedale (Lees, 1937). 1500 ft. above Llanthony,Black Mountains,Monmouthshire (E. W. Jones). In Wales 1000 ft.(304 m.) or higheron Llansannan,Denbigh (A. A. Dallman). In Irelandto 1000 ft. (304 m.) in the Mournes(Alt. Range Br. Pt.). In Europe it ascends to about 1000 m. (Switzerlandto 1050 m.) (Hegi, Fl. 2, 133). In the Swiss Jura it is recordedat 710 m. at La Clochatteand 810 m. at Vers-chez-lesBlanc (Bonner,1940). In Canton Graubiinden (Switzerland)it occursonly in the beech regionat 500-600 m. (Braun-Blanquet& Riibel, 1932). II. Habitat. (a) Climaticand topographicallimitations. In deciduouswoods, coppices, fox coverts,plantations, hedgerows, hedgebanks, scrubs, thickets, orchards, gardens, on wooded cliffs,and occasionally amongst the ground vegetation of marsh formations (alder-willowassociation). In dense woods it becomes marginal. For optimumgrowth it requiresa moist,loose soil,well suppliedwith humus. It seems to be equally abundantin woodlandof long standingas in woods whichare only 100-140 yearsold. Lightintensity determinations(actinometer) were made in Selsdon Wood, Surrey,by C. T. Prime (1943) duringthe periodof its active growth(March), and theyshowed that on a finesunny day, the average intensityinside the wood was 50% of the light outsidethe wood, but on an overcastday the averageintensity inside the wood was 95 % ofthe lightoutside the wood. The humiditywas determinedat the same time and showed the relativehumidity to be 73 % in the wood, and 61 % outsidethe wood. (b) Substratum.It is foundon a wide varietyof soils of highbase statusincluding sand, loam and calcareoussoils but is absent fromacid peaty ground. It toleratesconsiderable moisturebut also growson very poroushighly drained soils. Soil samples wereexamined fromthe followinglocalities: (i) Ravensdale, Derbyshire,on very stony limestone slopes amongst scrub with a humuslayer i-1 in. (ii) In Leicestershireon a heavy clay soil mixed with the 'Brand' series of slates the cormswere found 3 in. down. Therewas a sparselayer of dead leaves. (iii) In a mixedcoppice (oak-ash) on a dark clay for51 in. (corms)and then becoming lighter:

Water content(%) 46-3 16-8 22.5 Humus content(%) 23*6 6-74 6-64 Nitrates t - - Base deficiency(Comber) Carbonates(HCI test) + - - pH (elecrometric) 6.1 6-1 5 7 Its toleranceof wet conditionsis shownin Bishop Wood, near Selby,Yorks (alder-ash-elm) on Warp Clay. Soil a grey clay, with winterwater-table at about 4 in. fromsurface. Summerwater-table absent. Veryhigh exchangeable calcium content but verylow K and P04, pH of surfacesoil, 4-68; pH at 24 in., 6'58. The followingfigures (E. W. Jones) illustratethe limitationsin soil: In Dorset on chalk it is recordedin 16 out of 133 stands; of these 6 out of 16 occurrencesare on shallow chalk soils, and none on flintgravels or deep clay-with-flints.On Tertiarystrata it is presentin 1 out of 54 stands; this was in a planted stand of relativelyrecent origin on formerarable soil and was associated with other calcicoles. In the Chilterns(Watlington) it is recordedin 2 out of 44 stands on clay-with-flintson the plateau, and in 8 out of 9 stands on chalk soils of steep slopes. At J. Ecol. 37 14 210 Arummaculatum SymondsYat, Monmouthshire(High Meadow Woods) it is recordedin 75 out of 147 stands on CarboniferousLimestone, in 17% ofthe standson Old Red Sandstone(when it is local and confinedto moistvalley bottoms), and in 4 out of 100 stands on Coal Measureloams. In Wales and the Lake District,on Silurianand Ordovicianshales, it is a verylocal plant and in generalis presentin less than 1% of the stands. In the beech woods of the CranhamCommon-Painswick district (Cotswolds, Jurassic limestone) it is presentin 43 % of the stands. It invades abandoned arable land as shownby its presencein the interior of the oak-hazelwood successionin 1914 on the Broadbalk Wildernessat Rothamstead (Herts), abandonedin 1882 (Tansley,Br. IsI.). In ashwoods on limestonepavement it is an occasionalspecies. B. L. T. de Silva (1934) examinedthirteen soil samplesfrom various woodlandsin Kent where A. maculatumis present.These showed that it growsin soils rich in exchangeablecalcium even when calcium carbonateis absent. His observations gave a range of exchangeablecalcium from 4.5 to 19'9 m.equiv. withan average value of 12 3, whilstthe pH values rangedfrom 5'9 to 7 0 withan average value of 6 4. III. Communities.(a) Deciduous woodlhands.In Britain in pedunculate damp oakwoods on heavy soils,it is a commonassociate of Mercurialisperennis provided that the Mercuryshoots are not too dense (Tansley, Br. Isl.). Swampingby these shootsis sug- gested by the deseription(Jones, 1944) of the groundflora of a 30-year-oldhardwood plantationon calcareous gritnear Oxfordwhere the dominantM. perennisforms a 20- 100% cover and Arum maculatumis recordedas 'rare'. Otherimportant associates of this species are: Corylusavellana, Scilla non-scripta,Oxalis acetosella,Ranunculusftcaria, Anemonenemorosa, Ajuga reptans,Galeobdolon luteum, Primula vulgaris,Sanicula europaea, Asperulaodorata, Potentilla sterilis. In an oak (pedunculate)and Fraxinus wood in I-relandwhere the limestonelies practicallybare, it occurs with Quercus and Corylus avellana (co-dominants),Anemone nemorosa, Viola reichenbachiana,Oxalis acetosella,Geum urbanum,Circaea lutetiana,Viburnum opulus, Veronicachamaedrys, Prunella vulgaris, Neottianidus-avis, Epipactis atropurpurea,Scilla non-scripta,Carex sylvatica,Polystichum setiferum,Dryopteris filix-mas (Bot. Irl.). In sessile oakwoods on damp soil with mild humus with an undergrowthof Rubus spp., Rosa spp., Crataegusoxycanthoides, Hedera helix,Lonicera periclymenum, the fieldlayer contains Mercuralisperennis, Ranunculus ficaria, Anemonenemorosa, Deschampsia caespitosa,Holcus mollis, Digitalis purpurea, Melandrium dioicum, Stellaria holostea, Teucrium scorodonia,Pteridium aquilinum, Glecomahederacea, Ajuga reptansand Rumexacetosella. At Carrickreagh,Ireland, ridgesof bare limestonerise fromthe shore of Lough Erne and are coveredwith scrub which is continuallycut. Quercussessiliftora is sometimes don)inant,sometimes Betula pubescens,and sometimesCorylus with much Fraxinus, Viburnumopulus and Prunus spinosa. Arummaculatum is presentin the fieldlayer with Aquilegia vulgaris,Rubus saxatilis, Lysimachia nemorum,Prunella vulgaris,Epipactis helleborine,Scilla non-scriptaand Pteridiumaquilinum (Bot. Irl.). It is less frequentin Quercussessiliflora woods than in pure Quercusrobur or Fraxinus-Quercusrobur woods. (b) Compositionof communitiesin oak woods. (see Table 1). (1) Malvernianand Uriconianformation: light clayed loams, occasionallyfairly stiff clays; low humuscontent and watercontent may be low in dry weather. (2) Woods of May Hill Sandstoneon a loamy clay, generallyacidic. (3) Wenlocklimestone: Rock has highpercentage of calciumcarbonate but surfacesoil leached (lime contentless than 1 %). F.A.SOWTER 211 (4) Aymestrylimestone: Limestone nodules interbedded with shales. Lower lime contentthan the Wenlock limestone. Leaching of surfacelayers reduces lime content to usuallyless than 1 %. (5) In oak-hornbeamwoods of Hertfordshire(Salisbury, 1916, 1918) it is included amongstthe commonestspecies of the shade florain a mixedsociety, occupying the transi- tion regionbetween a damp societydominated by Mercurialisperennis and a dry society dominatedby Anemonenemorosa.

Table 1. Communitieswith Arum maculatum (a) Oakwoods Field layer ... 1 2 3 4 5 Arummaculatum o. l.c. f.-c. l .f. o.-I.c. Ajuga reptans + + f.-c. o.-f. l .?-l.c. Alliariapetiolata (margin) f. r. f. + Alliumursinum (flushes) . l.ab. l.f. l.c. Anemonenemorosa l.c. c.-l.ab. c. I.c. r.r.-I.c. Angelicasylvestris (flushes) + l.f. + 0. Anthoxanthumodoratum f. o.-f. + Arctiumvulgare c. + o.-f. f. r.r. Arenariatrinervia (margin) f.-c. + + o. r. Arrhenatherumelatius (margin) f. f. f. f. Asperulaodorata + f.-r. f -l.ab. o.-f.c. r.r.-l.f. Brachypodiumsylvaticum (margin) o. f. f.-c. f.-c. Bromusramosus r.r. r. o.-f. o. Campanula trachelium r. r. o.-f. + Cardamineflexuosa o. o. + + Carex sylvatica + f.-o. o. f. r. Chrysospleniumoppositifolium l.f. l.c. r.r. + Circaea lutetiana (damperplaces) o. f.-l.c. f.c. + r. Cirsiumpalustre o. l.f. o. + C. vulgare o. o. o. Clinopodiumvulgare f. o.-f. f.-ab. + Conopodiummajus + + + f. r.-r.r. Deschampsia caespitosa (flushes) 1. l.-o. r.r.-l.f. f. Digitalis purpurea c.-f. f.c.-c. r.-o. f. Dryopterisfijix-mas o. o. o. f. r.r.-v.r. Epilobium montanum f.-l.c. o.-f.c. f. + o. Euphorbia amygdaloides f.-c. f.-o. l.ab. f.-l.c. r.r.-l.f. Festuca gigantea(margin) l.f. r. o.-r. Filipendulaulmaria (flushes) ..f.c. l.f. l.f. Fragaria vesca f. f.-ab. c.-l.ab. f.-c. r.r. Galeobdolonluteum f. f.c.-c. f.-c. f. r.r.-f. Galium aparine o. + + + Geraniumrobertianum f.-fc. f. f. f. Geum urbanum f. + f. + r.r. Glecoma hederacea c.-l.ab. o. o.-f.c. 1.f. o.-l.ab. Holcus lanatus l.ab. f.c. f.c. + H. mollis c.-f. ab.-c. f.-c. l.ab. c.-r. Hypericumperforatum o.-f. r.-I.c. f. o. Luzula pilosa o.-l.f. c. r.r. f.-c. o.-f. Lysimachianemorum f. f.-c. o.-c. f. Melica uniflora f. f. f.c. f.c.-f. Mercuralisperennis c.-l.ab. l.c. ab.-c. c.-ab. l.ab.-r.r. Miliumeffusum . r. l.f.-r. r.r. Oxalis acetosella c. v.c.-c. o. f.-v.c. o.-f. Poa nemoralis(margin) c. c. f.-f.c. f.c.-v.c. Potentillasterilis + f.-f.c. f. o. Primulavulgaris o. o.-c. f.c.-c. f.-v.c. Prunellavulgaris + f. c. f.c. Pteridiumaquilinum I.c.-ab. l.ab.-f. r.-c. o.-r. v.c.-I.ab. Ranunculusauricomus . f. o.-f. 1.f. I.r. R. ficaria c. l.c.-f.c. l.ab. l.c. R. repens r.r.-f. l.f. + f. Sanicula europaea I.r. 1. f.c.-ab. c. r.r.-f. Scilla non-scripta r.r.-c. c.-l.ab. f.-c. f.-l.c r.r. Scrophularianodosa 0. o. o. o. r.r. 14-2 212 Arum maculatum Table 1 (continued) (a) Oakwoodl (continued) Field layer ... 1 2 3 4 5 Tamus communis o.-v.r. o. f.-c. r.r. Teucriumscorodonia (margin) f.-v.c. fc.-c. c. f.c.-c. O.-f. Urtica dioica f. + 0. Veronica chamaedrys f. f.-c. c. f V. montana + l.f. f. + r.r. V. officinalis l.f. c. o. + Viola reichenbachiana + 0. V.c. V.c. r.-o. V. riviniana + o.-c. v.c. v.c. r.-f (1) Beech woodlandsof the South Downs (Watt, 1924, 1925). (2) A beechwoodon chalk,Ditcham Park, Hampshire(Adamson, 1921). (a) WolverWood Series. Soil reactionpH 8. (b) The MiscombeSeries. Soil reactionpH 8-5. (c) Oakham Bottom. A calcicolouscoppice. Soil reactionpH 7. (3) A beechwoodof the CentralCotswolds on InferiorOolite (Tansley & Adamson,1913). It is presentin the groundvegetation in whichthere is no generaly dominantspecies. (b) Beechwoods Field layer 1 2(a) 2(b) 2(c) 3 Arummaculatum o.-l.f. o. o. 0. 0. Ajuga reptans o.-l.ab. o. o.-l.ab. f r. Arctiumminus o. o. o. * f. Arenariatriiiervia r.-l.f. . o. . 0. Asperulaodorata l.ab. f. Lab. f. ab. Brachypodiumsylvaticum o.-f. r. 1 o. ab. Carex sylvatica o. . . f. Chamaenerionangustifolium o.-I.d. l.a. . l.ab. o. Circaea lutetiana o.-Lab. 1. l.ab. 0. l.ab. Cirsiumpalustre r.-l.ab. . . r. o. C. vulgare l.-r. . . o. Clinopodiumvulgare o. . . o..f. Epilobium montanum o.-l.ab . o. o. f. Euphorbia amygdaloides o.-f. l.f. l.f. o. f. Fragaria vesca o.-l.ab. l.f. 1. ab. ab. Galeobdolonluteum l..l.ab. l.f. l.ab. f. o. Geraniumrobertianum o.-f.-l.ab. . r. o. f Geum urbanum o.-f. . r.-o. o. 0. Glecoma hederacea o.-l.ab. Melica uniflora o. . 1. . ab. Mercuralisperennis o.-I.d. o.-l.d. l.d. l.d. l.ab. Myosotisarvensis o. . r. 1. o. Primula vulgaris o.-f. . l.f.-.Lab. o. o. Prunella vulgaris o.-.Lab. Pteridiumaquilinum o.-l.ab. . 1. . l.ab. Ranunculusficaria r. . l.ab. Sanicula europaea r.-Lf. ab. o.-l.ab. ab.-f. ab. Scilla non-scripta lf.-l.ab. . l.ab. . l.ab. Scrophularianodosa 1. . o. o. Urtica dioica o.-l.d. . o. Veronicachamaedrys o.-f. o. o. 0. f. V. officinalis r.-.Lab. . r. . f. (c) Compositionof communitiesin beechwoods. On the Continentof Europe it is an importantconsituent of the fieldlayer of beechwoods. It is presentin the beechwood associes of many countrieswithin its continentalarea of distribution.It is foundwith Hepatica triloba,Ranunculus lanuginosus,Actaea spicata, Cardaminesilvatica, Sanicula europaea,Asperula odorata, Lysimachia nemorum, Vinca minor,Veronica montana, Asarum europaeum,Neotlia nidus-avis, Cephalanthera spp., Epipactis microphylta,Orchis purpurea, Cypripediumcalmeoltus, Melica uniflora,Hordeum europaeum (Lebensg. 1, iii, p. 34). In the beechwoodsof Britainit has an equally importantstatus (Table 1). F. A. SOWTER 213 In a fox covertof 'mixed' treeson chalkyboulder clay in northLincs Arummaculatum is associated with other marginalspecies, Viola odorata,V. riviniana,Geranium roberti- an&um,Bryonia dioica, Anthriscussylvestris, Torilis anthriscus,Chaerophyllum temulum, Lapsana communis,Glecoma hederacea and Stachyssylvatica (Woodruffe-Peacock, 1918). The authorsays these plants wereprobably not on the site whenthe covertwas planted, but have reachedit by followingthe fieldfences abutting on to the wood. In a Fraxinus coppice in Rutland on oolitic limestoneArum macutatumgrows in large clumps with Mercurialisperennis through a deep coveringmat of Porotrichumalopecurum. In hedgerowsof Crataegusmonogyna in Leicestershireit occurs with the following herbaceous plants: Ranunculus a,uricomus,R. ficaria, Alliaria petiolata, Metandrium dioicum,Stellaria media,Arenarta trinervia, Geum urbanum, Anthriscus sylvestris, Hedera helix, Galium aparine, Lamium album, Mercurialisperennis and Urtica dioica. In an orchardto whichit has spread froman adjoiningwoodland in northLancashire, it grows in the shade of the fruittrees with Ranunculusficaria, Viola riviniana,Myrrhis odorata, Primula vulgaris,Glecoma hederacea, Mercurialis perennis, Urtica dioica and Galanthus nivalis. IV. Responseto bioticfactors. Protected from grazing by the raphidescontained in the leaves, althoughon the Continentleaves have been foundin the stomachof the Common Crane (Grusgrus grus (L.)) (Jourdain,1940). It was observedin a Leicestershirewood in April 1946 that a large numberof spatheshad been bittenoff at the base. Some of them were afterwardsfound on the branchesof trees,and the damage can thereforeprobably be attributedto birds. This may be analogous to the destructionof otherspring flowers such as the primroseand crocus by birds,or they may be torn offby birds seekingthe slugs and snails whichenter the spathe forshelter. It was noticedthat this onlyoccurred to plants growingin the wood; plants growingunder hedgerows were untouched. Whilstcoppicing has the effectof reducingthe organiccontent of the surfacelayer and its correlatedacidity, the increasein lightintensity does not appear to have a detrimental effecton the plant. Afterclear felling,however, the plants are scorchedand depauperate in the followingseason. If regenerationis quick the plant will be saved fromextinction. The examinationof an area of woodlandswhich was clear-felled(Adamson, 1921) showed that Arummaculatum retained its frequencythree years later, A flora of tall herbs3-5 ft.in heightproviding the shade. V. (a) Gregariousness.(b) Performancein varioushabitats. Generally grows in 'clumps' or patches of irregularshape. Some clumps show great variation of individual plants, whilst others show similarity. Clumps showinggreat similarityare probably due to cloning.This has been investigatedby C. T. Primewho dug up and mapped the cormsof a uniformcolony. The directionof the growthof the cormswas compatiblewith asexual reproductionfrom the originalplants. Measurementsof leaves ofplants growingin clones show less variationin size than the leaves of plants chosenat random. (c) Effectof frost, drought, etc. The youngleaves are capable of withstandingfrost in spite of their succulentnature. Leaves exraminedin a spinneyin Leicestershirein the morningafter a sharp frostwere limp but were quite recoveredthree hours afterwards. The spathesare ruinedby cold dryingwinds and do not unroll(Church, 1908). Afterthe snowfallof 1 May 1945,many spatheswere affected and failedto mature.They remained in a shrunkengreen condition and did not open (E. W. Jones). VI. (a) Morphology.The slow-growingtuber is 2 cm. or morein diameterand contains 214 Arummaculatum the food reservesaccumulated during the summer. It is protectedagainst underground animalsby raphides. In autumna leaf bud is developedfor the next season's growth,and behindare one or morecorms of the previousyears on whichthere are ring-likeleaf scars and root remains.The stronglycontractile roots pull the.tubers to a depth of 20-30 cm. fromthe surface.Scott & Sargant(1898) examinedtubers which were 2 cm. below surface in May, and by Octoberthey were 7 cm. deep. Young tubersreplanted near the surface will regainnormal depth in a week. (b) Mycorrhiza.Endotrophic mycorrhizal association of the arbuscular-vesiculartype (Gallaud, 1915). Myceliumat firstintracellular, later intercellularis the usual course of events,but the firstcondition may be quite evanescent(M. C. Rayner). (c.) Perennration.Stem tubergeophyte. Thick unbranchedroots are foundon the tuber by September,and thenthere is a cessationof all growthduring the winter.By the end of Julythe leaves and spatheshave witheredand onlythe fleshy axis remains.This dies down afterthe dispersalof the berriesor is killedby the frost,and thoseberries which are not eaten decay on the surfaceof the soil. Thus nothingis visible above groundduring the winter. Daughter tubersare frequentand are budded offfrom the under-surfaceof the maturetuber. The plant producedfrom seed rarelyflowers before the seventhyear, whilst plants fromdaughter tubers flower much younger. Seed is set everyyear. C. T. Prime made countsof the numberof ovules ripening in the fruitsof the two formsof this species, and thepercentage of ripe seeds of the spotted plants was 39*4,whilst of the unspotted plants was 37-6. The average numberof ovules per gynaeciumwas 2-83 and 3-34respectively. (d). Chromosomenumber. The basic numberis n = 14. The followingvalues of 2n have been reported:2n=28, Danish material(Hagerup, 1942, in Love & Love, Scandinavian Flora); 2n = 32, northGerman material (Schmucker, 1925) (? errorfor 28); 2n = 56, British material,near Leeds (H. G. Baker, 1946); 2n = 56, Britishand German material(Mert. Cat. 1939); 2n = 84, British material (Mert.Cat. 1940). Maude says this variation can probablybe accountedfor by polyploidywithin the species. (e) Physiologicaldata. No information. VII. Phenology.Each springroots are developedbelow the leaf bud whenthe period ofmaximum growth commences. The leafbud forthe next season's growth is welldeveloped by the autumn,and its base thickensout to formthe tuberwhich will be initiatedin the followingspring. The leaves expand and uncoilfrom February to Marchor earlierin mild winters,e.g. in 1881, at Chelmsford,26 December, and in 1882 at SaffronWalden, 1 January.The leaves and spathesare coiled 'sinistrally'or 'dextrally',and accordingto Christy(1914) the leaves on any one plant are always coiled the same way as the flower spathe of that plant. This was furtherstudied and confirmedby Armitage(1921), who also foundthat there were hardlyever more 'dextrally' coiled than 'sinistrally'coiled spathes,i.e. five'lefts' to four'rights'. In the south of Britainit flowersearly in April, becominglater in more northerlystations. In Wiltshire,Preston (1888) gives the first flowering29 March1882 to 13 May 1879. Averagedate, 22 April.The flowersare over by the middleof June,and the leaves have mostlygone by the end of July. VIII. (a) Floral biology.Pollination is effectedby midgesof the genusPsychods which are attractedto theflowers by the emissionof an odourvariously described as ' ammoniacal' 'urinous', 'disagreeable', 'foetid', etc. The colour of the spadix is consideredalso to be a furtherattraction to the midges. Dung flieshave been observedto alighton the spadix, but theydo not enterthe spathe. There is a rise in temperatureof the tip of the spadix F.A.SOWTER 215 whichChurch (1908) recordsas 10-12? C. above the air temperature.The temperaturein the floralchamber also rises1-3? C. above the air temperature,and accordingto Dutrochet (in Balfour,1871) the maximumtemperature is reachedat about 17.30 hr. The starchin the spadix is used up duringthis active metabolism,and the spadix then becomeslimp. The midgesenter the chamberthrough the ringof stiff bristles, which allows them to enter but preventsthem from flying out untilthey have pollinatedthe femaleflowers with the foreignpollen which they have carriedin on theirbodies. The stigmasare receptiveon the firstday of opening. Afterpo1liiation the stigmasshrivel and a drop of nectaris exuded. The anthersdehisce and shed pollen on the imprisonedflies up to the 3 days afterwards, The ringof bristles then shrivels and allowsthe insects to escape. It has oftenbeen observed that if a spathe is cut open the imprisonedmidges immediatelyfly to another plant (Knuth, Poll. 3). Owing to the large numberof midgesfound dead in spathes, it was suggestedby the earlierbotanists that the plant is insectivorous,but thereis no evidence to supportthis (Arcangeli,1883). Thereis a suggestionthat these dead flieshave been suffocatedby C02 fromthe respiring spadix. The numberof midgesfound in spathes varies considerablyand up to 4000 has been recorded(Lebensg. 1, 33-45). Psychodaphalaenoides L. is the speciesmost commonly citedby writers.Tonnoir (1940) examinedthe insectsfound in spathesin variousparts of Britain (Herts, Surrey,Sussex, Devon) and the total numberof specimensof Psychoda determinedwere as follows:P. phalaenoidesL., o ', 158'; P. grisescensTonn., 14 , 19S; P. trinodulosaTonn., o, 2S; P. brevicornisTonn., 1 ', 2S; P. setigeraTonn., o s, 1 ; P. severiniTonn., o0, 1 S. Fromthese results he suspectedP. phalaenoidesto be partheno- genetic. Furtherinvestigations have been made, however,by G. H. Satchell (1944) of the midgesin spathescollected over two yearsnear Leeds. His recordsshowed that P. phailae- noideswas by far the most numerousvisitor with 205 Y in all and P. griscescenssecond with38 ? and 2(d. P. phalaenoideswas collectedfrom tree trunks near the Arumplants at the same time,and both sexes weretaken. The femalestaken from the Arumspathes were culturedand gave rise to both male and femaleoffspring. It seems,therefore, that Arum is attractiveto the femalefly only. Otherinsects such as smallbeetles, weevils, and aphids are oftenfound in the spatheswith slugs, spiders and earwigs,but these strayvisitors are probablymerely seeking shelter and warmth. (b) Hybrids.Colgan (1911) studiedthe 'unspotted' and 'spotted' formsof A. maculatum and suggestedthat the male parent was heterozygousfor 'spotted' characterand was fertilizedby the 'unspotted' form,but therewas no evidencein supportbeyond the equal proportionof the two formsamong the offspring:It has been shownby Schmuckerthat self-fertilizationand parthenogenesisdo not occur, and this has been confirmedby the writerwho blockednumbers of spathes with cotton-wool and foundthat no seeds wereset. C. T. Primealso 'bagged' plants,and out of 47 plants,only one set seed. He also blocked thespathes of two plants and no seed was set. Crosseswere also made by himof the extreme forms,and theredid not seem to be any failures.Plants of A. neglectum(Towns.) Ridley (A. italicumauct. angl.) withspotted leaves are consideredby Ridley (1938) to be hybrids with A. maculatum.The problemis being investigatedby H. G. Baker (1947), whose accumulatedevidence so farsuggests that A. maculatumand A. italicumhybridize in this country. (c) Seed productionand dispersal. Frequency distributionof the numberof fruiton 82 plants examined fromHertfordshire, Kent and Pembrokeshiregave 2428 + 0O34. 216 Arummaculatum Examinationof 175 fruitsshowed a rangein the numberof seeds: 1 (150), 2 (16), 3 (6), 4 (3). 86% containedonly one seed. The average seed output is 29-4+ 11 seeds per plant (cf. Fig. 28, p. 176 and Table 89, p. 177,Salisb. Rep. Capac.). Colgan(1911) examined661 ripe fruitsand foundan average of 1*4seeds per fruit.Average seed weightin grams= 0-04536 (Guppy, 1912). Seed dispersal. Ripe berriesfall offthe spadices or are dispersedby birds. Chaffinches (Fringillacoelebs gengleri Kleinschmidt) were observed to eat the berries(Scott & Sargent, 1898). Hulme(1902) saysthe seedA are eatenby manybirds, including pheasants and others.

b ~~~~~~c

d e

Fig. 2. Arummaculatum L. a-c, stages ofgermination: a, 9 days,the cotyledonhas emergedfrom the seed coat; b, 23 days,the tuberhas been formedby the thickeningof the hypocotyl;c, 44 days, contractileroots have appeared. All grownon filterpaper. x i. d, seedlingat the end ofthe secondyear. The stembud is exposed. Grownin soil in pots. x a. e, thirdyear, the first(ovate) leaf. Grownin soil in pots. x 86s

(d) Viabilityof seeds and specialconditions affecting germination. Sets ofseeds werekept in Petridishes at roomtemperature in daylightand in darkness. Germinationin daylight, nil. Germinationin the dark, 20 %. Sets of seeds taken from'unspotted' and 'spotted' leaved plants wereplanted in soil in pots out of doorsand wereexamined for germination in the second year. The soil was frozenduring the firstwinter. The followingresults were recorded: 'spotted' seed 85-71% germination,'unspotted' seed 91-66% germination F. A. SOWTER 217 (Sowter,1945). The resultof a germinationtest made by Salisbury (Rep. Capac. p. 177) was under 6%. Wattam (1938) planted 40 seeds in pots in the spring,and the contents of the pots were frozenduring the winter. Germinationwas 100%. (e) Seedlingmorphology. In Britain, as on the Continent,the seeds germinatein the ~earlyspring. Firstthe seed swellsand the cotyledonemerges from the seed coat (Fig. 2 a). Then the hypocotylthickens out to formthe tuber from which grow two or threecontractile roots (Fig. 2 b,c). In the second season the seed coat is detached and the stem bud is exposed (Fig. 2d). Accordingto Scott & Sargant (1898) no chlorophyllis formedand nothingis seen above ground. In the germinationexperiments made by the writerin soil, a largepercentage of the seedlingsshowed a greenleaf tip just above soil level. New roots (4-6) are sent out duringthe summer. As a rule it is not until the thirdyear (Fig. 2e) that the firstleaf appears above the surface,although Irmisch (1850) and Colgan (1911) report the firstleaf in the autumn of the second year as an exception.The firstleaf is ovate. Below groundthe tuber increasesin size until June, when next year's tuber is initiated.The tuber is pulled deeper in the groundeach season by the contractileroots whichare producedat the end of the summer. It also moves its positionfrom vertical to horizontal. In the fourthor fifthyear the firsthastate leaf is formed,and floweringrarely occursbefore the seventhyear. (f) Effectivereproduction. Examination of clumps suggests that reproductionby vegetativemeans is moreimportant than multiplicationby seed. In addition to having a ready-madesupply of foodstuff the tubersstart at theirnormal depth in the groundand the Tiskof beingeaten is thereforealmost eliminated. IX. (a) Animalfeedersor parasites. Several thripshave, been taken but are considered to be casual visitorsprobably not feeding(G. D. Morrison). No Cecidomyidsare known to be associated with it (H. F. Barnes). The oil beetle (Meloe proscarabacus)sometimes feedson this plant (Briggs,1880). (b) Plant parasites. The alga Phyllosiphonarisari Kuhn (Siphonales) which is oc- casionallyparasitic on the leaves in Italy and the south of France (West & Fritsch,1927) has been foundon plantsin Scotlandat TillietudlemCastle near Lanark. It causes yellow spots on the leaves (J. Caldwell). The followingfungi are recorded: BASIDIOMYCETES UREDINALES: . Caeoma ari-itali'ci(Req.) Rud., near Salisbury, 1897 (Br. Rust. F. p. 388); also foundin France and Germany.Puccinia phalaridisPlowr. Aecida on Arum maculatumMay-July (Br. Rust. F. p. 269).

FUNGI IMPERFECTI HYPHOMYCETES: Macrosporiumignobile Karst Ayrshire,A. L. Smith & Ramsbottom, 1913 (Trans. Brit. Mycol. Soc. 4, 183); Ramularia arnFautr. at ChippingCampden (List Hyphomyc.p. 94).

COELOMYCETES: Ascochytaari Died. (Syn. A. aricola A. L. Smith & Ramsbt,tom) (Br. Stemand Leaf F. 1, 321).

X. History. There are no geologicalrecords. 218 Arummaculatum XI. General. The starch obtained fromthe rhizomeshas in the past been used for severalpurposes. In the Isle of Portlandthe starchextracted was sold as 'Portland Sago' (Henslow, 1905). In Elizabethan timesit was used to starchthe lawn ruffsworn during that period. In Switzerlandthe rhizomeshave been used as a substitutefor soap. Medi- cinallythe action of a small dose of the powderedroot is diaphoretic.Fatal effectshave been recordedfrom large doses. Childrenhave died fromeating the berries.The toxic principleis believed to be saponin. Animals exceptionallyeat the plant (Long, 1924). Observationsmade in Leicestershirenear Badger 'setts' suggestthat this animal grubs forthe rootsin winter.Pigs eat the roots(Cornevin, 1887). GilbertWhite (1789) says the roots are scratchedout fromhedgebanks and eaten by birdsin winter.

REFERENCES Adamson, R. S. (1921). Studies of the vegetationof the English chalk. Pt. 1. The woodlands of Ditcham Park, Hampshire. J. Ecol. 9, 113. Arber, A. (1925). Monocotyledons.Cambridge. Arcangeli, G. (1883). Osservazionesull' impollinazionein alcune Aracee. Nuovo G. bot.ital. 15, 72. Armitage, E. (1914). Vegetationof the Wye Gorgeat SymondsYat. J. F&ol.2, 98. Armitage, E. (1921). Some observationson Arummaculatum. Lanes. Che8h.Nat. 13, 121. Babington, C. C. (1839). PrimitiaeFlorae Sarnicae. London. Battandier, J. A. & Trabut, L. (1902). Flore Analytiqueet Synoptiquede l'Algerieet de la Tunisie. Alger. Baker, H. G. (1947). Criteriaof hybridity.Nature, Lond., 159, 221. Bonner, C. E. B. (1940). Itudefloristiquedu Jorat. London. Braun-Blanquet, J. & Rilbel, E. (1932). Flora von Graubunden,1. Bern and Berlin. Briggs, T. R. A. (1880). Flora of Plymouth.Plymouth. Bromfield, W. A. (1856). Flora Vectensi8.London. Burbidge, F. W. (1903). The leaf-markingof Arumnmaculatum. Irish Nat. 12, 137. Campbell, M. S. (1936). Three weeksbotanizing in the OuterHebrides. Rep. Bot. (Soc.) Exch. Cl. 11, 315. Christy, M. (1914). The coilingof Arumspathes. J. Bot.,Lond., 52, 258. Christy, R. M. & Corder, H. (1883). Arum maculatumand its cross-fertilization.J. Bot.,Lond., 21, 235, 262. Church, A. H. (1908). Types of Flora Mechanism,1. Oxford. Colgan, N. (1903). The leaf markingof Arummaculatum. Irish Nat. 12, 78. Colgan, N. (1911). On the inheritanceof pitted leaf blotchingsin Arummaculatum and on floralvariations in the species. Irish Nat. 20, 210. Cornevin, C. (1887). Des plantsvninneuses. Paris. Darlington, C. D. & Janaki Ammal, E. K. (1945). ChrorhosomeAtlas of CultivatedPlants. London. Darwin, C. (1878). Crossand Self-fertilizationof Plants. London. De Silva, B. L. T. (1934). The distributionof calcicole and calcifugespecies in relationto the contentof the soil in calcium carbonateand' exchangeable calcium and to soil reaction. J. Ecol. 22, 532. Dickie, G. (1864). Flora of U18ter.Belfast. Fritsch, F. E. & Salisbury, E. J. (1938). Plant Form and Function. London. Gallaud, I. (1915). Etudes sur les mycorhizesendotrophes. Rev. ge'n.Bot. 17, 5, 66, 123, 223, 313, 423, 479. Gaye, S. (1885). Some facts about Arums. Midl. Nat. 8, 301. Gerard, J. (1905). Arummaculatum and its relationwith insects. J. Bot., Lond., 43, 23. Gunn, W. F. (1903). Arum maculatumagain. Irish Nat. 12, 219. Guppy, H. (1912). Studiesin Seeds and Fruits. London. Henslow, G. (1905). The Uses ofBritish Plants. London. Horwood, A. R. & Gaisborough, Earl of (1933). Flora of Leicestershireand Rutland. Oxford. Hulme, F. E. (1902). Wild Fruit of theCountryside. London. Huxley, J. (1942). Evolution-The ModernSynthesis. London. Irmisch, T. (1850). Zur Morphologieder MonokotylischenKnollen- uend Zwiebelgewa4chse. Berlin. Jahandiez, E. & Maire, R. (1931). Cataloguedes Plantesdu Maroc,1, 107. James, W. 0. & Clapham, A. B. (1935). Biologyof Flowers. Oxford. Jones, E. W. (1944). BiologicalFlora. Acerpseudo-plantanus L. J. Ecol. 32, 215. Jourdain, F. C. B. (1940). The Handbookof BritishBirds, 4, 453. London. F. A. SOWTER 219 Kerner, A. (v. Marilaun) & Oliver, F. W. (1894). The Natural Historyof Plants, 2, 165. London. Lees, F. A. (1937). The vegetationof Craven-in-Wharfedale.Suppl. Northw.Nat. 91. Long, H. C. (1924). Plants Poisonous toLivestock. Cambridge. Lubbock, Sir. J. (1897). BritishWild Floers in Relationto Insects. London. Marquand, E. D. (1901). Flora of Guernseyand theLesser ChannelIslands. London. Martin, I. H. (1934). The Field-Club.Flora of theLothians. Edinburgh. Martin, W. K. & Fraser, G. T. (1939). Flora of Devon. Arbroath. Masters, M. T. (1865). A monstrosityof Arummaculatum. J. Bot., Land., 3, 110. Mukerji, S. K. (1936). Contributionsto the autecologyof Mercuralisperennis L. J. Ecol. 24, 38. Overton, E. (1899). Beobachtungenund Versuchefiber das Auftretenvon rothemZeilsaft bei Pflanzen. Jb. wiss. Bot. 33, 171. Pearsall, W. H. (1938). The soil complexin relationto plant communities.II. Characteristicwoodland soils. J. Ecol. 26, 207. Pethybridge, G. H. (1903). The leaf-spotsof Arum maoulatum.Irish Nat. 12, 145. Pillips, R. A. (1903). Notes on Arummaculatum. Irish Nat. 12, 204. Pick, H. (1883). tber die Bedeutungdes rothenFarbstoffes. Bot. Zbl. 16, 281, 314, 343, 375. Preston, T. A. (1888). The Floweringplants of Wilts. Leicester. Raunkiaer, C. (1934). Life Forms of Plants. Oxford. Rayner, M. C. (1927). Mycorrhiza.Cambridge. Ridley, H. N. (1938). On Arumneglectum (Towns.) Ridley. Rep. B.E.C. p. 29. Salisbury, E. J. (1916). The oak-hombeamwoods of Hertfordshire.Pts. I, II. J. Ecol. 4, 105. Salisbury, E. J. (1918). The oak-hornbeamwoods of Hertfordshire.Pts. III, IV. J. Ecol. 6, 14. Salisbury, E. J. (1925). The vegetationof the Forest of Wyre: a preliminaryaccount. J. Ecol. 13, 314. Salisbury, E. J. (1939). Ecological aspects of meteorology.Quart. J. R. Met. Soc. 65, 337-58. Salisbury, E. J. & Tansley, A. G. (1921). The Durmastoak woods (QuercUssesiliflorae) of the Silurian and Malvernianstrata near Malvern. J. Ecol. 9, 19. Salmon, C. E. (1923). Arum maculatumvar. te*reliiCorb. J. Bot., Lond., 61, 314. Scott, (Mrs) D. H. & Sargant, E. (1898). On {the developmentof Arum maculatumfrom the seed. Ann. Bot., Oxford,12, 399. Stahl, E. (1896). tber bunte Laubbliitter. Ann. Jard. bot.Buitenzorg, 13, 137-216. Tansley, A. G. (1911). Types of BritishVegetation. Cambridge. Tansley, A. G. & Adamson, R. S. (1913). Reconnaissance in the Cotswolds and the Forest of Dean. J. Ecol. 1, 81. Tonnoir, A. L. (1940). A synopsisof the BritishPsychodidae (Diptera) withdescriptions of new species. Trans. Soc. Brit. Ent. 7, pt. 2, 51. Watt, A. S. (1925). On the ecologyof BritishBeechwoods with special referenceto theirregeneration. Pt. II. The Developmentand structureof beech communitieson the Sussex Downs. J. Ecol. 12, 145. Pt. II. SectionsII, HII. J. Ecol. 13, 27. Watt, A. S. (1934). The vegetationof the ChilternHills, with special referenceto the Beechwoodsand their seral relationships.J. Ecol. 22, 230, 445. Wattam, W. E. L. (1938). Notes on seeds and seedlings-Arummaculatum L. Naturalist,p. 183. West, G. S. & Fritsch, F. E. (1927). BritishFreshwater Algae. Cambridge. Wheldale, M. (1916). The AnthocyaninPigments of Plants. Cambridge. White, F. B. W. (1898). Flora of Perthshire.Edinburgh. White, G. (1789). The Natural Historyof Selborne. London. Wilson, A. (1938). Flora of Westmorland.Arbroath. Wolley-Dod, A. H. (1937). Flora of Sussex. Hastings. Woodruffe-Peacock, E. A. (1918). A fox-covertstudy. J. Ecol. 6, 110. Young, W. (1936). Floweringplants and fernsfrom Fife and Kinross (v.-c. 85). Trans. Bot. Soc. Edinb. 32, 143.