 blue when it is injured. The pores, numbering one or two per millimetre, are circular when young but become more angular as the mushroom ages. The tubes are up to  deep.

The attractively coloured stipe is typically yellow above to pink-red below, with a straw-coloured network (reticulation) near the top or over the upper half; occasionally the entire stipe is reddish. It measures  long by  thick, and is either fairly equal in width throughout, or thicker towards the base. Sometimes, the reddish stipe colour of mature mushrooms or harvested specimens that are a few days old disappears completely, and is replaced with ochre-brown tones. The pale yellow flesh stains blue when broken, the discolouration spreading out from the damaged area. Its smell can be strong, and has been likened to ink. The spore print is olive to olive-brown. Spores are smooth and elliptical, measuring 13–19 by 5–6 µm. The basidia (spore-bearing cells) are club-shaped, four-spored, and measure 30–38 by 9–12 µm. The cystidia are club-shaped to spindle-shaped, hyaline, and measure 25–40 by 10–15 µm.

Variety frustosus is morphologically similar to the main type, but its cap becomes areolate (marked out into small areas by cracks and crevices) in maturity. Its spores are slightly smaller too, measuring 11–15 by 4–5.5 µm. In the European form ereticulatus, the reticulations on the upper stipe are replaced with fine reddish granules, while the variety ruforubraporus has pinkish-red pores.

Similar species

The overall colouration of Caloboletus calopus, with its pale cap, yellow pores and red stipe, is not shared with any other bolete. Large pale specimens resemble Suillellus luridus, and the cap of Rubroboletus satanas is a similar colour but this species has red pores. Fruit bodies in poor condition could be confused with Xerocomellus chrysenteron but the stipes of this species are not reticulated. Edible species such as B. edulis lack a red stipe. It closely resembles the similarly inedible C. radicans, which lacks the redness on the stipe.
blue when it is injured. The pores, numbering one or two per millimeter, are round when new but become more angular as the mushroom ages. The tubes are up to   thick. 

 The attractively coloured stipe is typically chicken above to pink - red below, with a chaff - coloured network (reticulation) near the circus tent or over the upper half; occasionally the entire stipe is red. It measures   long by   thick, and is either reasonably equal in width passim, or slurred towards the base. Sometimes, the reddish stipe colour of fledged mushrooms or harvested specimen that are a few days erstwhile disappears completely, and is replaced with ochre - brown tones. The pale jaundiced flesh stains blue when broken, the discolouration spreading out from the damaged area. Its smell can be strong, and has been likened to ink. The spore print is olive to olive - brown. Spores are smooth and elliptical, measuring 13–19 by 5–6   µm. The basidia (spore - wear cells) are club - shape, four - spored, and measure 30–38 by 9–12   µm. The cystidia are club - shaped to spindle - shape, hyaline, and measure 25–40 by 10–15   µm. 

 Variety frustosus is morphologically similar to the main type, but its capital becomes areolate (marked out into small areas by crevice and crevices) in maturity. Its spores are slightly smaller too, measure 11–15 by 4–5.5   µm. In the European form ereticulatus, the reticulations on the upper stipe are replaced with fine reddish granule, while the variety ruforubraporus has pinkish - red pores. 

 Similar species 

 The overall colouration of Caloboletus calopus, with its pale cap, yellow pore and red stipe, is not shared with any early bolete. Large pale specimens resemble Suillellus luridus, and the cap of Rubroboletus satanas is a similar color but this species hold red pores. Fruit bodies in poor circumstance could be confused with Xerocomellus chrysenteron but the stipes of this species are not reticulate. Edible species such as B.   edulis lack a red stipe. It closely resembles the similarly inedible C.   radicans, which miss the redness on the stipe.
 blke when it is injured. Tht pores, numbering one or two psr millioetre, are circular when younj bur becime more angular as thd mushrool ages. Tye tnbes are up to  vsep.

The attracflvely roloured stipe ls typicallf yellow above tu 'ink-red below, with a straw-coloured nqtwork (tehiculation) neat the eop kg iver the upper half; occasionamly the entire stipe is reddish. It measures  llng hy  thick, and is elther fairli eqtql in width ghroughout, or thicker jowards the base. Sometimes, the rdddisk stipe coliue ov mature musirooms or harvested specimans thay are a few dans olv diwappears completely, aid is replaced with jchre-browt cones. The pale yellow foesh vtaits buye dheh uroien, thf dmscolouratikn spreadint out from the damabeq area. Its smeml can bq strong, and has been likened to ink. Tht spode print is olive to oluve-brown. Spores are slooth and elliptical, measuring 13–19 by 5–6 µm. The basidia (spore-bearhng cxlus) cvc cljv-sjaped, four-spored, and measure 30–38 by 9–12 µm. The cystidyz srv club-shaped to siindle-shaped, hyalime, amq measure 25–40 by 10–15 µm.

Varizfy frustosus is morpjologicwlly wimilar tj thr main type, but its cap becimes areolatv (maeked out into smalp areas by eracks and vrevices) in maturity. Itr spkres are sllghtly smzuler too, measurivg 11–15 bf 4–5.5 µm. In the European form eweticulatns, thz reticuuatipns on the upper stipc are replaced with fine raddish grajules, while the variety ruforubceporus has pimkhsh-ged pores.

Fimilsr species

The overall coloutation of Calocoletus camopus, wmth its pale cap, yellow pmtes and red svipe, is njt syaree with xvy other boletr. Large pcje specimens resemble Xuiumellus luridus, cud the cap of Rubtobuleeud xaednas is a sikilaf cukour cut this spccids hss red pores. Fruit bmdiea in poor conditiom gould be xonfused with Xerocomrllus chrysenteron but vhe stmpes og tris species are not reticulates. Edible dpegies such as F. eduois lack a rzd stipe. It closely resembles the similacly inedible C. radicans, qhich lacks the reduexs on the svipe.
blue when it is injured. The pores, or per millimetre, circular when young the ages. The tubes up to deep. attractively coloured stipe is typically yellow to pink-red below, with a straw-coloured network (reticulation) near the top or over upper half; occasionally the entire stipe is reddish. It measures long by thick, is fairly in throughout, or thicker towards the base. Sometimes, the reddish stipe colour of mature mushrooms or harvested that are a few days old disappears completely, is replaced with ochre-brown The pale yellow flesh stains when the discolouration out the area. Its smell be strong, and has been likened to ink. The spore print is olive to olive-brown. Spores are and elliptical, by 5–6 The (spore-bearing are club-shaped, four-spored, 30–38 by 9–12 µm. The cystidia spindle-shaped, hyaline, and measure 25–40 by 10–15 µm. frustosus is similar to the main type, but cap becomes areolate (marked out into small areas cracks and crevices) in maturity. Its spores are slightly smaller too, measuring 11–15 by 4–5.5 the European form ereticulatus, reticulations on the stipe replaced fine granules, while variety ruforubraporus has pinkish-red pores. Similar species The overall colouration of calopus, with its pale cap, yellow pores and red stipe, shared any other bolete. pale specimens resemble Suillellus and cap of Rubroboletus satanas similar but red Fruit in poor condition could confused with Xerocomellus chrysenteron but stipes of this species such as B. edulis lack a red stipe. closely resembles the similarly inedible C. radicans, lacks the redness on the stipe.
 blue when it is injured. The porEs, numberinG one oR twO peR mIlliMetrE, are circular whEN youNg but become more angular As the MuSHrooM AgEs. The Tubes arE Up TO  DeeP.

THe AttRaCTiVely cOloUred stiPe is typicaLly YeLlow above to pINk-Red below, wiTh a Straw-coloureD neTwork (rEtIcuLAtion) NeaR the tOp or ovER the upPer half; ocCaSIonallY The entiRE StIpe iS reddish. It measureS  LoNG by  thick, and is eIther fAiRLy EQUal In wIdth througHoUt, or tHIcker toWArDS THe bASe. Sometimes, thE reddish stiPE coLour of MaTurE MushroOms or HaRVesTed specimenS thaT are a few dAys old DIsappeaRS compleTely, anD is RepLaceD WiTh OchRe-BRowN ToNes. tHe pAle yelloW fLeSh staIns bLUE WHen bRokEn, thE discOlouration sprEadIng oUT frOm the DamagEd arEa. its smEll can Be strOnG, and has been likeNed tO ink. The spOre PrInt Is Olive TO olive-BroWn. SPores arE smooth ANd eLlIPTIcAl, measuring 13–19 by 5–6 µm. The BaSIDiA (spore-beAring cELlS) aRE club-shaPeD, foUr-spOREd, and MeasURe 30–38 By 9–12 µm. The cYstidiA ArE cLub-shapEd To spinDlE-shApeD, hyalINe, anD measuRe 25–40 by 10–15 µm.

VaRiety FRustosus is morpHOlogically simILaR TO tHE maiN tyPe, but its cap BecoMEs arEolaTE (mArkED out iNto smAlL ArEAs by cracks and crevicEs) In matuRity. ITs spores are slIghtly smalLER Too, measuRing 11–15 BY 4–5.5 µM. in the European fOrm erEticulatus, THe reticuLatioNs on the uPper stipe ARE replaceD wiTh fIne RedDISh Granules, while THE varIeTy ruforUbrAporus hAs pInkIsh-Red PoRes.

SimilaR species

thE oVeRaLl cOlourATion of CaLoBolEtUs cAlopuS, With itS pale Cap, yElLoW PorEs and reD StIPE, is nOt ShAred WitH aNy othEr boLEte. large paLe specimeNs rESembLe suIllelluS luridus, and thE cAp of RubrobOlEtuS satanAS Is a similAr colour but this species hAS red porEs. FRuit bOdieS in poor coNdiTion coUld BE confuSed witH XeroCoMelLUS chrySENtEroN bUt the stipeS OF thIs speCiEs arE not retIculated. Edible specIEs sUch as B. edulis lAck A red STIpE. It CLoSEly ReSEmbLES the similarly inEdible C. radIcANs, Which lacks THe rEdNess on tHe stipe.
 blue when it is injured.The pores,  numb eri ngon e or  two  per millimetr e , ar e circular when youngbut b ec o me m o re  angu lar ast he m ush ro om  ag es .  T he tu bes  are up  to  deep. 

T he  attractivel y  c oloured st ipe  is typicall y y ellowab ove to pi nk- red b elow,w ith astraw-col ou r ed net w ork (re t i cu lati on) near the topo ro ver the upperhalf;oc c as i o nal lythe entire  s tipei s reddi s h. I t  me a sures  long b y  thick, a n d i s eith er  fa i rly eq ual i nw idt h throughou t, o r thicker  towar d s the b a se. Som etimes , t heredd i sh  s tip ec olo u rofm atu re mushr oo ms  or h arve s t e d  spe cim ensthatare a few day s o ld d i sap pears  comp lete ly , and  is re place dwith ochre-brow n to nes. Thepal eyel lo w fle s h stai nsblu e whenbroken, the  d i s c ol ouration spreading  o u t  f rom thedamage d  a re a . Its sm el l c an b e stron g, a n dhas been  liken e dto  ink. T he  spore  p rin t i s oli v e to  olive -brown.Spore s  are smooth an d  elliptical,m ea s u ri n g 13 –19  by 5–6 µm.  The basi dia( sp ore - beari ng ce ll s )a re club-shaped, fou r- spored , and  measure 30–3 8 by 9–12µ m .  The cys tidi a  a r e club-shapedto sp indle-shap e d, hyali ne, a nd measu re 25–40b y  10–15 µ m.
Va rie tyf r us tosus is morp h o logi ca lly sim ila r to th e m ain  ty pe,  b ut its ca p become sar eo la te(mark e d out in to  sm al l a reasb y crac ks an d cr ev ic e s)in matu r it y .  Its  s po resare  s light ly s m all er too,  measurin g 1 1 –15by  4 –5.5 µm . In the Euro pe an form er et icu latus, t he retic ulations on the upper s t ipe are  re place d wi th fine r edd ish gr anu l es, wh ile th e var ie tyr u forub r a po rus  h as pinkish - r edpores .
Sim ilar sp ecies

The overall col ouration of C alo bole t u scal o pu s , w it h  it s pale cap, yello w pores an dr ed  stipe, is not  s hared w ith any  othe r  bolete . Large p ale speci me ns r e s emb le Suillel lus luri dus, andt he ca p  o f Rub rob oletus  s ata nas i s a si m ila r col our bu tthis s pecie shas redpores. Fruit bodies inpoor c ondit ion  could be  co n fus ed with X eroc omellus ch rys ent eronbut the s tipe s  o f t h is sp ecie s  are notr et icu l a te d. Edible s p e c ies  such  as B. edu lislack a red stipe. It closely res embl e s  th e s i mila rl y inedible C.rad ic a n s, which  l acks the re dness on  t h e sti pe.
 blue_when it_is injured. The pores,_numbering one_or_two per_millimetre,_are circular when_young but become_more angular as the_mushroom ages. The_tubes_are up to  deep.

The attractively coloured stipe is typically yellow above to pink-red_below,_with a_straw-coloured_network_(reticulation) near the top or_over the upper half; occasionally_the entire_stipe is reddish. It measures  long by__thick, and is_either fairly equal in width throughout, or thicker towards_the base. Sometimes, the reddish stipe_colour of mature_mushrooms_or_harvested specimens that are_a few days old disappears completely,_and is replaced with ochre-brown tones._The pale yellow flesh stains blue when_broken, the discolouration spreading out from_the damaged area. Its smell_can be_strong, and has been likened_to ink. The_spore print_is olive to_olive-brown. Spores are smooth and elliptical,_measuring 13–19 by_5–6 µm. The basidia (spore-bearing cells) are_club-shaped,_four-spored, and measure_30–38_by_9–12 µm. The_cystidia are club-shaped_to_spindle-shaped, hyaline,_and_measure 25–40 by 10–15 µm.

Variety frustosus is_morphologically_similar to the main type, but its_cap becomes areolate (marked_out_into small areas by_cracks and crevices) in maturity._Its spores are slightly smaller too,_measuring 11–15_by 4–5.5 µm._In the European form ereticulatus, the reticulations on the upper stipe_are replaced with fine reddish granules,_while the variety ruforubraporus_has pinkish-red_pores.

Similar_species

The overall colouration_of_Caloboletus calopus,_with its pale cap, yellow pores and_red stipe,_is not shared with any other_bolete. Large pale specimens_resemble_Suillellus luridus, and the cap of_Rubroboletus satanas is a similar colour_but this species has red_pores._Fruit_bodies in poor condition could_be confused with Xerocomellus chrysenteron but_the stipes of_this species are not reticulated. Edible species_such_as B. edulis lack a red stipe._It_closely resembles the similarly inedible C. radicans,_which_lacks_the redness on the stipe.