The Genus Biarum
The Genus Biarum by Peter Boyce

Biarum Schott nom. cons. in Schott & Endlicher, Melet. Bot. 17 (1832) & Syn. Aroid. 6 (1856) & Gen. Aroid. t.7 (1858) & Prodr. Syst. Aroid. 60-64 (1860); Pfeiffer, Nomen. Bot. 1(1): 403-404 (1873); Engler in A. & C. DC., Monog. Phanerog. 2: 571-580 (1879) & in Engler & Prantl., Die Natürl. Pflanzenfam. 149 (1889) & in Engler, Pflanzenr. 73(IV.23F): 132-143 (1920); Riedl in Aroideana 3(1): 24-31 (1980). Type: B. tenuifolium (L.) Schott. Homaïd Adans., Fam. Pl. 2:470 (1763) in syn. nom. rejic.; Pfeiffer, Nomen. Bot. 1(2): 1658 (1874). Type: H. tenuifolium (L.) Adans.

Ischarum Schott & Kotschy, Oesterr. Bot. Wochen. 4: 81 (1854); Schott, Syn. Aroid. 6-8 (1856) & Gen. Aroid. t.10 (1858) & Prod. Syst. Aroid. 65-70 (1860); Pfeiffer, Nomen. Bot. 1(2):1764 (1874). Type: I. bovei (Blume) Schott (See Nicolson 1967).

Leptopetion Schott, Gen. Aroid. t.8 (1858) & Prodr. Syst. Aroid. 64 (1860). Type: L. alexandrinum (Boiss.) Schott. Cyllenium Schott, Gen. Aroid. t.9 (1858) & Prodr. Syst. Aroid. 64-65 (1860). Type: C. spruneri (Boiss.) Schott.

Stenurus Salis., Gen. Pl. 5 (1866). Type: S. tenuifolium (L.) Salis. Homaida Adans. emend O. Kuntze, Rev. Gen. Pl. 2: 742 (1891). Type: H. tenuifolium (L.) Adans. emend O. Kuntze.

Dwarf tuberous stemmed herbs. Tuber dorso-ventrally compressed-discoid to ± globose, encased basally by remains of the previous season's tuber, growth point central, peripheral adventitious buds none to many, usually giving rise to independent tubers, tuber apex coated with moderate to copious amounts of waxy farina and bearing the remains of the previous season's cataphylls; roots simple, emitted in a ring around the growth point, contractile or feeding; contractile roots fusiform, usually thick, feeding roots slender, cylindrical. Foliage hysteranthous, occasionally synanthous, rarely proteranthous, petiolate., petiole sometimes ± subterranean, leaves erect or, rarely, reflexed; petioles enclosed proximally by several cataphylls, the inner papery and the outer fibrous, these often emerging above ground and encasing the basal part of the aerial shoot, petioles terete proximally, canaliculate and expanded into a membranous wing distally, petioles enclosing one another, forming a weakly defined aerial pseudostem in some species; leaf lamina linear, lanceolate, elliptic-oblong or spathulate, decurrent, ± cuneate, rounded or ± truncate apically, acute to obtuse basally, margins smooth to undulate, rarely crispulate, mid-, light, bright or deep green, rarely with green or black-purple bullae or silver-grey spotting. Inflorescence ± sessile on the tuber or borne on a short to rather long, subterranean peduncle, rarely peduncle emerging above ground, smeling foetid or sweet. Spathe divisible into a tubular lower portion (spathe tube) and a ± expanded upper portion (spathe limb); spathe tube narrow to inflated, sometimes greatly so, constricted distally or not, emergent to partially buried, rarely entirely subterranean, margins partially to fully connate, sometimes convolute distally, exterior deep purple to dirty green or greenish purple above, ± white below, interior off-white below, purple above, or wholly purple or off-white with purple staining at the base around the pistillate flowers; spathe limb large to small, rarely ± absent, linear, lanceolate or elliptic, erect, reflexed or deflexed, flat to recurved and coiled or strongly involute; exterior dirty green, more rarely mid-green, dirty white, dull yellow or pinkish brown sometimes with purple spotting and staining; interior deep purple-brown, yellow or pale greenish, sometimes purple with a green apex, apex subacute, acute to acuminate, margins smooth to undulate, rarely crispulate. Spadix shorter than, equalling or exceeding the spathe limb, divided into distinct zones; a sterile terminal appendix, an zone of staminodes (subgenus Biarum), a fertile male zone, a stamino-pistillate interstice, a further zone of staminodes (sometimes absent) and a fertile female zone; terminal appendix sessile to stipitate, cylindrical to fusiform, erect to flexuous, apex acute to rounded, tapering, base rarely rounded or sub-truncate, smooth, very rarely furnished with filamentous processes proximally, deep purple, brown-red or brown, occasionally greenish, rarely dirty yellow. Flowers: supra staminal staminodes present only in subgen. Biarum, arranged in few to several irregular whorls, simple or 1 &# 2-branched, hooked, peg-like or filamentous, partially expanded proximally, glossy, cream; staminate flowers arranged in a cylindrical, globose or oblong zone, each comprising two anthers, connective short to ± absent, rarely prolonged into a ± prominent beak, thecae dehiscing by coalesced or separate apical pores (subgen. Isharum) or ventral longitudinal slits (subgen. Biarum), cream to purple; pollen free or in strands, exine spinose or smooth, interflora staminodes usually confined to the base of the stamino-pistillate interstice, more rarely arranged evenly over the whole area or absent, slender-filiform to hooked, simple to 1-3-branched, recurved, decurved or tangled, cream, off-white or purple; pistillate flowers arranged in a hemispherical cluster at the base of the spadix, ovary oblong, sub-globose or bottle-shaped, off-white to purple, uniovulate with a basal placenta, ovules orthotropous, style slender to rather stout or absent, stigma capitate, pale greyish or purple. Infructescence subterranean or partially emergent, globose berries many, globose to pyriform, white to lilac- or purple-stained, stigmatic remnents slightly prominent or not; seed ovoid to globose, large to small with a large elaiosome at the hilum, testa leathery, ± smooth to reticulate, pale to dark brown, endosperm copious, embryo straight; eophyll lanceolate to spathulate.

Infrageneric Classification

Subgenus Biarum
[Biarum Sectio 1 Blume, Rumphia 1:112 (1836)]
[Biarum Subgen. Eubiarum Engler in A. & C. DC., Monog. Phanerog. 2: 572 (1879) & in Engler,
Das Pflanzenr. 73 (IV.23F):134 (1920)]
[Biarum sect. Eubiarum (Engler) Boiss., Fl. Or. 5:31 (1882)]
Biarum subgenus Cyllenium (Schott) Engler in A. & C. DC., Monog. Phanerog. 2:574 (1879);
Engler in Engler, Das Pflanzenr. 73 (IV.23F):136 (1920). Type: B. spruneri Boiss.
Cyllenium Schott, Gen. Aroid. t.9 (1858). Type: C. spruneri (Boiss.) Schott
Biarum sect. Cyllenium (Schott) Boiss., Fl. Or. 5:32 (1882).
Thecae dehiscing by ventral, longitudinal slits, connective beak-like and extending beyond the anther surface. Staminodes hooked, rarely peg-like or filamentous, mostly present above and below male flower zone, rarely present only below the amle flower zone and then hooked.

1a. tenuifolium subsp. tenuifolium
1b. tenuifolium subsp. zelebori
1c. tenuifolium subsp. arundanum
1d. tenuifolium subsp. galianii
1e. tenuifolium subsp. abbreviatum
1f. tenuifolium subsp. idomenaeum
2. rhopalospadix

Subgenus Ischarum (Blume) Engler in A. & C. DC. Monog. Phanerog. 2: 575 (1879). Type: I. bovei (Blume) Schott (See Nicolson 1967).
Ischarum (Blume) Reichb., Deutsche Bot. Bd.1 Herbuch Nom. 32 (1841) & Schott & Kotschy,
Oesterr. Bot. Wochen. 4: 81 (1854).
Biarum section Ischarum Blume, Rumphia 1: 112 (1836), Boiss., Fl. Or. 5: 32 (1882).
Thecae dehiscing by apical pores, connective barely prominent or flush with the anther surface. Staminodes absent above male flower zone.

3. aleppicum
4. angustatum
5. carduchorum
6. eximium
7. bovei
8. crispulum
9. dispar
10. olivieri
11. straussii
12. syriacum
13. carratracense
14. kotschyi
15. fraasianum
16. pyrami
17. mendax
18. auraniticum
19. ditschianum
20. davisii
21. marmarisense


1. Staminodes occurring above and below the staminate flower zone   2
    Staminodes absent above the staminate flower zone; present or absent
2. Staminodes hooked   3
    Staminodes not hooked   6
3. Staminodes simple, very rarely branched   4
    Staminodes always 2 – 3 branched   5
4. Leaf lamina 15 – 25 cm x 11 – 15 mm; spadix appendix
   10 – 41 cm x 2 – 3 mm; leaves in mature individuals
   oblong-lanceolate early in the season, linear-lanceolate
    later in the season
  1a. tenuifolium subsp. tenuifolium
    Leaf lamina 20 – 40 cm x 16 – 21 mm; spadix appendix
    10 – 12 x 4 – 9 mm; leaves in mature individuals always
  1b. tenuifolium subsp. zelebori
5. Leaf lamina oblanceolate to linear-lanceolate; staminodes
    2-branched, arranged in c. 8 regular whorls.
    Plants of heavy terra rossa soils
  1c. tenuifolium subsp. arundanum
    Leaf lamina linear; staminodes 2 – 3-branched, arranged in
    c. 7 irregular whorls. Plants of loose sandy soils
  1d. tenuifolium subsp. galianii
6. Staminodes peg-like; leaf lamina spathulate, erect, margins
    gently undulate
  1e. tenuifolium subsp. abbreviatum
    Staminodes filamentous; leaf lamina linear-oblong, usually
    adpressed to the ground, margins strongly
    undulate- crispulate
  1f. tenuifolium subsp. idomenaeum
7. Staminodes hooked, stiff, thickened Thecae dehiscing by
    ventral longitudinal slits, connective rostrate
  2. rhopalospadix
    Staminodes filiform, flexuous, or absent, never hooked and
    thickened Thecae dehiscing by apical pores, connective
    barely prominent or flush with the anther surface
8. Spadix appendix massively thickened with reflexed basal
    ‘hairs’; spathe limb much reduced, recurved
  19. ditschianum
    Spadix appendix with no ornamentation; spathe limb well
    developed or, if reduced, then erect, cucullate
9. Spathe limb usually much shorter than the spathe tube,
    margins recurved, spathe tube enclosing much of the
    Spathe limb exceeding the spathe tube in length, flat or
    with the margins inrolled, spathe tube enclosing the base
    of the spadix only
10. Spathe 5 – 6 cm long, spadix appendix 3 – 3.5 cm long x 2 mm
  20. davisii
      Spathe 7 – 8 cm long, spadix appendix 3.5 – 5 cm long x 0.5 mm
  21. marmarisense
11. Spathe tube not inflated, the sides ± parallel   12
      Spathe tube inflated, the sides ± gibbous   14
12. Spathe tube margins free ± to the base; stigmas not borne on a stipe 3 aleppicum
      Spathe tube margins free for a quarter of their length; stigmas borne
      on a short to moderately long stipe
13. Staminodes directed downwards; leaves narrowly lanceolate-elliptic
  4. angustatum
      Staminodes directed upwards; leaves elliptic to broadly
  5. carduchorum
14. Spathe tube distinctly wider than the spathe limb,
      the margins joined for their entire length; spathe limb
      appearing linear due to inrolled margins; spadix
      appendix filiform
  10. olivieri
      Spathe tube as wide as or narrower than the spathe limb, the
      margins free for at least a quarter of their length
15. Foliage proteranthous   16
      Foliage hysteranthous or synanthous   17
16. Leaf lamina ovate-elliptic, oblong or linear; staminodes
      restricted to the bottom quarter to third of the interstice
  11. straussii
      Leaf lamina in mature plants linear to linear-elliptic; staminodes
      distributed over the basal half of the interstice
  12. syriacum
17. Staminodes distributed evenly over the interstice separating the
      staminate and pistillate flower zones
  6. eximium
      Staminodes arranged mostly above the pistillate flower zone,
      intersticial staminodes adjacent to the staminate flower zone
      much reduced or vestigial, or staminodes absent
18. Spathe limb interior greenish white, spadix appendix yellow   18. auraniticum
      Spathe limb interior deep purple-brown; spadix appendix
      similarly coloured
19. Spathe tube margins free for quarter to half their length   20
      Spathe tube margins free for three quarters their length   21
20. Spathe tube margins free for half their length, staminodes few,
      SW Spain
  13. carratracense
      Spathe tube margins free for a quarter of their length,
      S Greece
  15. fraasianum
21. Spadix appendix c. 2 – 4 mm in diam., slender-cylindric, to
      slender-fusiform, appearing + consistent diameter
      Spadix appendix more than 4 mm in diam., fusiform, widest
      below the middle
22. Spathe tube globose; interstice twice as long as the staminate
       flower zone; staminodes very few or absent
  9. dispar
      Spathe tube oblong; interstice equalling the staminate flower
      zone; staminodes many
23. Foliage hysteranthous; spathe limb lanceolate, margins
  7 bovei
      Foliage synanthous; spathe limb linear-lanceolate, margins
  8. crispulum
24. Spathe tube oblong, spathe limb narrowly lanceolate, acute,
      seldom exceeding 10 cm
  14. kotschyi
      Spathe tube globose, spathe limb lanceolate, acuminate,
      exceeding 12 cm
25. Spathe tube margins fully fused; spathe limb remaining erect
      during flowering
  17. mendax
      Spathe tube margins for _ of their length ; spathe limb
      reflexing and curling during flowering
  16. pyrami


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