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DELTA sample data

M. J. Dallwitz and L. Watson

Character list


#1. Including <synonyms: ‘genera’ included in the current description>/

The data would be improved by inclusion of nomenclatural references. At present, they are given only for genera not covered by Clayton and Renvoize (1986).

Habit, vegetative morphology

#2. <Longevity of plants>/

1. annual <or biennial, without remains of old sheaths or culms>/

2. perennial <with remains of old sheaths and/or culms>/

‘Annual’: plants progressing from germination to seed production and perishing, within that period.

‘Biennial’ (not known in grasses?): a plant normally requiring two years to complete its life-cycle, growing vegetatively in the first, then flowering, fruiting and perishing in the second.

‘Perennial’: a plant which persists and continues growth for several to many years. Detectable in herbaceous grasses by the shrivelled remnants of old sheaths and culms.

#3. <Mature> culms <maximum height: data unreliable for large genera>/

cm high/

#4. Culms <whether woody or herbaceous>/

1. woody and persistent/

2. herbaceous <not woody, not persistent>/

#5. Culms <whether branched above>/

1. branched <vegetatively> above/

2. unbranched <vegetatively> above/

#6. Culm nodes <whether hairy or glabrous>/

1. hairy/

2. glabrous/

#7. Leaf blades <shape: data incomplete>/

1. linear/

2. linear-lanceolate/

3. lanceolate/

4. ovate-lanceolate/

5. ovate/

6. elliptic <oblong>/

7. obovate/

#8. Leaf blades <mid-width: data very incomplete>/

mm wide/

#9. Leaf blades <whether pseudopetiolate>/

1. pseudopetiolate/

2. not pseudopetiolate <<implicit>>/

#10. <Adaxial> ligule <presence>/

1. <consistently> present <<implicit>>/

2. absent <at least from upper leaves>/

#11. <Adaxial> ligule <form; avoid seedlings>/

1. an unfringed membrane <may be variously hairy or ciliolate>/

2. a fringed membrane/

3. a fringe of hairs/

4. a rim of minute papillae/


#12. Plants <whether monoecious, with bisexual spikelets, or dioecious>/

1. <bisexual, but> monoecious with all the fertile spikelets unisexual/

2. bisexual, with <at least some> bisexual spikelets/

3. dioecious <with separate male and female-fertile individuals>/

#13. Inflorescence <chasmogamous: overall form>/

1. a single spike/

2. of spicate <spike-like> main branches <of spikes, narrow racemes or narrow panicles>/

3. a false spike, with spikelets <or spikelet clusters> on contracted axes/

4. a single raceme <at least some of the spikelets clearly pedicellate>/

5. paniculate <and not readily referable to any of the other states>/

In the absence of a suite of characters to deal satisfactorily with general inflorescence form, this has to suffice. Note that the coded data are frequently supplemented by important data comments, and forms for which these states are inappropriate are described exclusively via comments.

#14. Inflorescence <whether open or contracted: mainly applied to panicles>/

1. open/

2. contracted <very compact, or narrow and spike-like>/

#15. Inflorescence <whether comprising a complex of ‘partial inflorescences’ and intervening foliar organs (= leaves, spathes, spatheoles)>/

1. a complex of ‘partial inflorescences’ and intervening foliar organs <i.e., a ‘pseudo-inflorescence’>/

2. not comprising ‘partial inflorescences’ and foliar organs/

#16. Spikelet-bearing axes <whether disarticulating; note that spikelet-bearing axes may be greatly reduced>/

1. disarticulating <often manifested in clearly articulated rachides; excluding inflorescences falling whole (tumbleweeds)>/

2. persistent <not disarticulating> <<implicit>>/

#17. Spikelet-bearing axes <manner of disarticulation>/

1. falling entire/

2. disarticulating at the joints/

#18. Spikelets <grouping: recorded mainly in spikes and racemes>/

1. <mainly> solitary/

2. <consistently> paired/

3. <consistently> in triplets/

#19. Spikelets <whether secund>/

1. secund/

2. not secund/

Currently a catch-all character, covering one-sidedness of inflorescence; e.g. Dactylis, dorsiventral rachides, etc.

#20. Spikelets <whether in regular ‘long-and-short’ combinations, as exemplified in typical andropogonoids>/

1. consistently in ‘long-and-short’ combinations <i.e., pedicellate/sessile or long-pedicel/short-pedicel pairs or triplets: currently includes andropogonoid forms with the pedicellate ‘spikelets’ reduced to their pedicels>/

2. not <consistently> in distinct ‘long-and-short’ combinations <<implicit>>/

#21. Spikelets <detail of ‘long-and-short’ combinations (intended mainly for andropogonoids)>/

1. in pedicellate/sessile combinations/

2. unequally pedicellate in each combination/

#22. Pedicels of the ‘pedicellate’ spikelets <whether fused with the rachis: intended for andropogonoids>/

1. discernible, but <extensively> fused with the rachis/

2. free of the rachis/

#23. The ‘shorter’ <andropogonoid> spikelets <sessile or shorter-pedicelled, sexuality>/

1. hermaphrodite/

2. female-only/

3. male-only/

4. sterile/

#24. The ‘longer’ <andropogonoid> spikelets <pedicelled or longer-pedicelled, sexuality>/

1. hermaphrodite/

2. female-only/

3. male-only/

4. sterile <comment if reduced to pedicels>/

Female-sterile spikelets

#25. <Comments on female-sterile spikelets>/

Female-fertile spikelets, florets, fruit

#26. <Female-fertile> spikelets <approximate length, excluding any awns>/

mm long/

Data unreliable for large genera.

#27. <Female-fertile> spikelets <plane of compression>/

1. compressed laterally <lying on the side when placed on a flat surface>/

2. not noticeably compressed <terete>/

3. compressed <dorsally, ventrally or> dorsiventrally <lying on front or back when placed on a flat surface>/

#28. <Female-fertile> spikelets <location of disarticulation positions>/

1. <readily> disarticulating above the glumes <when mature>/

2. disarticulating between the glumes/

3. falling with the glumes <when mature> <pending data changes, including forms where the spikelets are shed by inflorescence disarticulation>/

4. not disarticulating <common in cultivated cereals>/

#29. <Female-fertile> spikelets <whether rachilla disarticulates between the florets of spikelets with two or more fertile florets>/

1. not disarticulating between the florets/

2. disarticulating between the florets/

#30. Rachilla <of female-fertile spikelets, whether terminated by a female-fertile floret, or ‘prolonged’>/

1. prolonged beyond the uppermost female-fertile floret <i.e. not terminated by a female-fertile floret: note that ‘racemose’ spikelets with three or more female-fertile florets have all been awarded this state>/

2. terminated by a female-fertile floret <not ‘prolonged’>/

#31. Hairy callus <presence>/

1. present/

2. absent/

An unsatisfactory catch-all character, but widely recorded and useful in keys.

#32. Glumes <of female-fertile spikelets, present or absent>/

1. present <<implicit>>/

2. absent/

#33. Glumes <of female-fertile spikelets, number: ‘glumes’ are barren, with neither axillary spikelets nor florets>/

1. one per spikelet/

2. two/

3. several/

#34. Glumes <of female-fertile spikelets, whether markedly unequal in the intact spikelet; regardless of any differences in form>/

1. very unequal <in length in the intact spikelet>/

2. more or less equal <in length in the intact spikelet: generally includes ‘subequal’>/

#35. Glumes <of female-fertile spikelets, lengths relative to proximal (adjacent) lemmas; refers to the longer glume when glumes unequal>/

1. <decidedly> shorter than the adjacent lemmas <in intact spikelets>/

2. long relative to the adjacent lemmas <more or less equalling or exceeding them>/

#36. Glumes <of female-fertile spikelets, whether awned>/

1. awned/

2. awnless/

#37. Glumes <of female-fertile spikelets, whether carinate (i.e., one-keeled to middle or below)>/

1. carinate <one-keeled>/

2. non-carinate <includes forms with more than one keel, as well as those with non-keeled glumes>/

#38. Upper glume <(or the single glume) of female-fertile spikelets, mid-zone nerve number>/


#39. <Female-fertile> spikelets <whether containing sterile or male-only florets in addition to female-fertile florets>/

1. <normally> with female-fertile florets only/

2. <or at least some of them, normally> with incomplete <sterile or male-only> florets <note that the situation at the apex of spikelets with more than three florets is often unknown or unclear>/

#40. The incomplete <male or sterile> florets <position in spikelet>/

1. proximal to the female-fertile florets/

2. distal to the female-fertile florets/

3. both distal and proximal to the female-fertile florets/

#41. The proximal incomplete florets <of the female-fertile spikelets, when present, number (intended mainly for panicoids)>/

#42. The proximal incomplete florets <of the female-fertile spikelets: sexuality>/

1. male/

2. sterile/

#43. The proximal <imperfect> lemmas <of the female-fertile spikelets: whether awned>/

1. awned/

2. awnless/

#44. <Number of> female-fertile florets <per female-fertile spikelet>/

#45. <Female-fertile> lemmas <shape of apex>/

1. entire/

2. incised/

#46. <Female-fertile> lemmas <entire, whether pointed or blunt>/

1. pointed/

2. blunt/

#47. <Female-fertile> lemmas <whether mucronate or awned>/

1. awnless <neither mucronate nor awned>/

2. mucronate <with a short, hard point or vestigial or incipient awn>/

3. awned/

#48. Awns <of female-fertile lemmas, if present, number>/

#49. Awns <of female-fertile lemmas, position of (main, median)>/

1. from a sinus/

2. dorsal/

3. apical/

#50. Awns <of female-fertile lemmas, whether straight or geniculate when dry>/

1. non-geniculate <straight or curved>/

2. geniculate <usually twisted at the base>/

#51. Awns <main, median of the female-fertile lemmas, relative length>/

1. much shorter than the body of the lemma/

2. about as long as the body of the lemma/

3. much longer than the body of the lemma/

#52. <Female-fertile> lemmas <whether carinate (i.e., one-keeled at least to the middle on the back)>/

1. carinate <with a single median keel>/

2. non-carinate <rounded, flat, with two or more keels>/

#53. <Female-fertile> lemmas <presence of germination flap>/

1. with a clear germination flap <when mature>/

2. without a germination flap/

#54. <Female-fertile> lemmas <number of nerves traversing mid-region>/


#55. Palea <female-fertile, presence in female-fertile florets>/

1. present/

2. absent/

#56. Palea <female-fertile, relative size>/

1. relatively long <three-quarters or more of female-fertile lemma length>/

2. conspicuous but relatively short <less than three-quarters of female-fertile lemma length>/

3. very reduced <or vestigial>/

#57. Lodicules <presence in female-fertile florets>/

1. present/

2. absent/

#58. Lodicules <of female-fertile florets, texture>/

1. <distally> fleshy <‘cuneate’; panicoid type>/

2. <distally> membranous <i.e. pooid type>/

#59. Lodicules <of female-fertile florets, whether hairy>/

1. ciliate <or hairy>/

2. glabrous/

#60. Stamens <number per female-fertile floret (not applicable to male spikelets or male florets)>/

#61. Ovary <of female-fertile florets, whether apex glabrous or hairy>/

1. glabrous/

2. hairy/

#62. Stigmas <number>/

#63. Stigmas <colour, in chasmogamous spikelets>/

1. white/

2. red <anthocyanin> pigmented/

3. <golden> brown/

#64. Fruit <length when mature>/

1. small <less than 4 mm>/

2. medium sized <4–10 mm>/

3. large <more than 10 mm long>/

#65. Fruit <or grain surface pattern>/

1. sculptured/

2. <relatively> smooth <the near-universal condition: implicit>/

#66. Hilum <form>/

1. short <punctiform or shortly elliptical, less than half length of fruit>/

2. long-linear <more than half as long as fruit>/

#67. Pericarp <whether fused or loose (or free)>/

1. free/

2. loosely adherent <fairly easily removable when soaked>/

3. fused <implicit, except in Arundinoideae and Chloridoideae>/

Photosynthetic pathway, leaf blade anatomy

#68. <Maximum cells-distant count; reliably indicative of photosynthetic pathway>/

1. <showing a maximum cells-distant count of one, reliably predicting> C4/

2. <showing a maximum cells-distant count of two or more, reliably predicting> C3/

‘Maximum cells-distant count’: the maximum number of cells separating any individual chlorenchymatous mesophyll or photosynthetic carbon assimilation (PCA) cell from the nearest parenchymatous bundle sheath (PBS) or photosynthetic carbon reduction (PCR) cell. This parameter defines the relatively unambiguous ‘one cell distant criterion’, whereby C3 and C4 forms are reliably and easily distinguished. By contrast, C3/C4 assignments by ‘radiateness’ of chlorenchyma, or by recognition of ‘Kranz’/‘non-Kranz’ anatomy, are less satisfactory: ‘radiateness’ is ambiguous and is often misleading, and many C4 leaves (Arundinella, Triodia etc.) do not exhibit typical ‘Kranz’ anatomy.

The terms PCA (primary carbon assimilation) and PCR (photosynthetic carbon reduction: containing Rubisco) are applicable to the cells and tissues of C4 forms only. For these, the term PCR is preferable to ‘Kranz’, since it is directly indicative of physiological function, and PCR cells do not always occur in ‘Kranz’ bundle sheaths.

For detailed discussion, see Hattersley and Watson (1975) and Hattersley et al. (1977).

#69. <C4> biochemical type <as determined by enzyme assay>/

1. PCK/

2. NAD–ME/


See Hatch and Kagawa 1974, Gutierrez et al. 1974(a) and 1974(b), Hatch, Kagawa and Craig 1975, and Prendergast, Hattersley and Stone 1987. Species samples in parentheses.

#70. <Leaf blade XyMS: reliably indicative of C4 type>/

1. XyMS+ <C3, or C4 ‘aspartate formers’ type PCK or NAD–ME (exceptions: Eriachneae)>/

2. XyMS– <C4 ‘malate formers’, type NADP–ME>/

Refers to the presence (XyMS+) or absence (XyMS–) of cells between the metaxylem vessel elements and laterally adjacent chlorenchymatous bundle sheath (CBS, ‘Kranz’ or PCR: C4) or parenchymatous bundle sheath (PBS: C3) cells in the primary lateral vascular bundles (i.e. in the largest bundles exhibiting both metaxylem and protoxylem) of the leaf blade (see Hattersley and Watson 1976). When properly applied, this unambiguous criterion reliably distinguishes NADP-ME species (XyMS–) from PCK and NAD-ME species (both XyMS+). The terms MS (mestome sheath) and PS (parenchymatous sheath) of Brown (1975, 1977) refer to the supposed homologies of photosynthetic carbon reduction (PCR, ‘Kranz’) sheaths in C4 forms. The MS condition is identified by XyMS–, the PS one by XyMS+. Dengler et al. (1985) provide comparative ontological evidence in support of the MS/PS hypothesis.

For recent detailed discussion of C4 anatomical tissue configurations and physiological types, see Hattersley (1992) and Hattersley and Watson (1993).

#71. <Leaf blade> mesophyll <presence of arm cells (= ‘ratchet’ cells)>/

1. with arm cells/

2. without arm cells <implicit when ts adequately described>/

All the leaf anatomical data in these descriptions refer to preparations made from the mid-zone of the laminae of ‘normal’, mature leaves. To obtain reliably comparative data, avoid seedling and flag leaves, culm leaves with blades reduced or missing, and conspicuously unhealthy material. Attempted identification of leaf fragments should be conducted with these sampling considerations in mind, and the results qualified accordingly. For detailed discussion of these matters, and further information on character state definitions, see Metcalfe (1960), Clifford and Watson (1977).

#72. <Leaf blade> mesophyll <presence of fusoid cells>/

1. with fusoids/

2. without fusoids <implicit when ts adequately described>/

#73. Midrib <of the leaf blade, prominence>/

1. conspicuous <prominent in the outline, with distinctive sclerenchyma, etc.>/

2. not readily distinguishable <other than by position>/

#74. Midrib <of the mid leaf blade, vascularization>/

1. with one bundle only/

2. having a conventional arc of bundles <i.e. at least three bundles>/

3. having complex vascularization <i.e. with more than one bundle, not arranged in a conventional arc>/

#75. Midrib <and/or middle part of leaf blade, whether extensively of colourless cells adaxially>/

1. with <conspicuous> colourless tissue adaxially/

2. without <conspicuous> colourless tissue adaxially <implicit when ts adequately described>/

#76. <Presence in the leaf blade of small vascular bundles unaccompanied by sclerenchyma>/

1. many of the smallest vascular bundles unaccompanied by sclerenchyma/

2. all <or nearly all> the vascular bundles accompanied by sclerenchyma/

Special diagnostic feature

#77. <Zea mays>/

1. fruiting inflorescence a massive, spatheate cob, the fruits in many rows/

2. fruiting inflorescence not as in maize <<implicit>>/

Taxonomy, distribution

#78. <Subfamily>/

1. Pooideae/

2. Bambusoideae/

3. Arundinoideae/

4. Chloridoideae/

5. Panicoideae/

Subfamilies updated from Watson et al. (1985).

#79. <Supertribes of Watson et al. 1985, with name endings changed>/

1. Triticodae/

2. Poodae/

3. Oryzodae/

4. Bambusodae/

5. Panicodae/

6. Andropogonodae/

Supertribes updated from Watson et al. (1985), with name endings changed.

#80. <Tribe of Pooideae>/

1. Triticeae/

2. Brachypodieae/

3. Bromeae/

4. Aveneae <including Agrostideae, Phalarideae>/

5. Meliceae/

6. Seslerieae/

7. Poeae <including Hainardieae, Monermeae>/

#81. <Tribe of Bambusoideae>/

1. Oryzeae/

2. Olyreae/

3. Centotheceae/

4. Anomochloeae/

5. Brachyelytreae/

6. Diarrheneae/

7. Ehrharteae/

8. Phaenospermateae/

9. Phyllorhachideae/

10. Phareae/

11. Streptochaeteae/

12. Streptogyneae/

13. Guaduelleae/

14. Puelieae/

15. Bambuseae/

#82. <Tribe of Arundinoideae>/

1. Steyermarkochloeae/

2. Stipeae/

3. Nardeae/

4. Lygeae/

5. Arundineae/

6. Danthonieae <and satellites>/

7. Cyperochloeae/

8. Micraireae/

9. Spartochloeae/

10. Aristideae/

11. Eriachneae/

12. Amphipogoneae/

#83. <Tribe/assemblage of Chloridoideae>/

1. Pappophoreae/

2. Orcuttieae/

3. Triodieae/

4. main chloridoid assemblage <including Chlorideae, Cynodonteae, Eragrosteae, Sporoboleae, Aeluropodeae, Jouveae, Unioleae, Leptureae, Lappagineae, Spartineae, Trageae, Perotideae, Pommereulleae>/

#84. <Tribe of Panicoideae>/

1. Isachneae/

2. Paniceae/

3. Neurachneae/

4. Arundinelleae/

5. Andropogoneae/

6. Maydeae/

#85. <Number of species>/


#86. <Floristic Kingdoms: after Takhtajan 1969>/

1. Holarctic/

2. Paleotropical/

3. Neotropical/

4. Cape/

5. Australian/

6. Antarctic/

The phytogeographical Kingdoms, Subkingdoms, Regions and Subregions are those of Takhtajan (1969). The data, which are complete, were provided by B.K. Simon (1987). They are intended to reflect ‘natural’ distributions, insofar as these are determinable.

Anatomical references

#87. <Leaf anatomical references>/

‘This project’ denotes original observations by Watson, or for Pooideae by Macfarlane (1979) supplemented by Watson. Taxonomic realignments (extensive in Triticeae) have been accounted for when using Metcalfe (1960).


#88. <Illustrations:>/

#89. <Abbreviated taxon name:>/

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa. See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1998 onwards. DELTA sample data: descriptions, illustrations, identification, and information retrieval. Version: 19th October 2016.’.