Stomatal ontogeny and phylogeny. I. Monocotyledons G.S. Paliwal Department of Botany, University of Delhi, Delhi, India 1. introduction The study of the cuticle in living and fossil gymnosperms has made it abundantly clear that stomatal and other epidermal characters are often of great value not only in the delimitation of genera but also in distinguishing the fragmentary fossil remains of allied species (see Florin 1931, 1933, 1958). In the early thirties of the present century, two comprehensive works appeared dealing with the systematic valueof these characters in the living and fossil angiosperms. The first by Odell (1932) describes the cuticle in 84 genera of the living angiosperms and the conclusion is reached that of the features of the none epidermal vege- tative of the fossil is for parts living or angiosperms really satisfactory diagnostic work. Contrary to this Edwards (1935) stated that the structural differences in the leaf epidermis do provide a means of distinguishing some closely related taxonomic groups. He, however, argued that as with other features in classi- fication a sum total of the epidermal characters must be taken into account. Since the appearance of these two publications, a considerable body of data absence has accumulated regarding the cuticle. However, in the of any com- prehensive account, it was thought worthwhile to bring together the available information this it under two on aspect. I propose to complete separate articles, the first one will deal with the monocotyledons and the second with the dicoty- ledons. A “stoma” two cells the enclosed In comprises guard surrounding pore. some plants the epidermal cells adjacent to the stoma also become modified in shape, size and contents and are thenknown as subsidiary or accessory cells. Ontogene- tically they may or may not be related to the guard cells. The stoma along with the subsidiary cells, when present, is termed as the “stomatal apparatus” or the “stomatal complex”. led to As stated earlier, Florin’s pioneering work on gymnosperms the appre- ciation of the fundamentalvalue of the epidermal features in interpreting rela- this idea the tionships between major groups of plants. The basis for was opinion held the of divisions to the of by him that sequence leading arrangement cells in the mature stomatal complex is a relatively fixed character in a leaf. Although several recent works tend to suggest that there is much more variation than what Florin had appreciated, his investigations have stimulated a good deal of the and of in subsequent work on morphology ontogeny stomata ferns, gymnosperms and dicotyledons. As regards the monocotyledons the most comprehensive work is that of Stebbins & Khush (1961) who have attached great phylogenetic significance to 654 Acta Bot. Need. 18(5), Oct. 1969 STOMATAL ONTOGENY AND PHYTOGENY I this feature based on two assumptions: (I) that the developmental modes are from and that the and constant, organ to organ within a plant, (2) genera even families exhibit constancy for their possession of a particular complex. A brief of the recent literature, indicates that in several instances, survey however, e.g. & Roy Ananas comosus (Krauss 1948), Oryza sativa (Richharia 1961), Panda- members of the Philydraceae and nus spp. (Tomlinson 1965), (Hamann 1966) still others, the results are at variance with those of Stebbins Khush. The to evaluate and reconsider of the present paper is, therefore, an attempt some this The that deserves main consideration is prevalent ideas on subject. point that these authors appear to have failed to demarcate between observations and inferences and one is unable to understand the bases of comparisons between different families, whether these are purely morphological, or developmental, or both. 2. CLASSIFICATION AND TERMINOLOGY have been made of Although attempts towards classifying the stomata gym- and nosperms dicotyledons (see works of Vesque, 1889; Florin, 1931; Met- and later calfe & Chalk 1950; publications of Metcalfe; Pant 1965; and serious has been Guyot 1966), no thought paid to the proper grouping ofthese or- We know of in which gans in monocotyledons. only the gramineous type stomata cells have two lateral subsidiary along the dumb-bell-shaped guard cells and are characteristic of and Gramineae. so Cyperaceae Morerecently Metcalfe(1961, the term for such which 1962) gave tetracytic stomata are accompanied by 2 cells lateral and 2 polar subsidiary as seen in some members of the Commelina- two terms ceae. However, these are hardly sufficient to demarcate the various encountered the types of stomata among monocotyledons. of the above realization, Stebbins & Khush made of In view (1961) 4 groups the basis of the and the these stomata on number, shape arrangement of subsi- the first in the order there diary cells. In group represented Liliales, are no The second with subsidiary cells. category two or more subsidiary cells sur- rounding the guard cells is found in members of the Cyperaceae, Gramineae, Haemadoraceae, Juncaceae, Pontederiaceae, and Xanthorrhoeaceae. The have four or more remaining two categories subsidiary cells and are represented in the families Agavaceae, Araceae, Commelinaceae, Palmae, and Pandanaceae. has Although this attempt helped to remedy the situation to a certain extent, suitable in the absence of any terminology it becomes extremely difficult to imagine any particular type immediately on looking at a given preparation. like the I would, therefore, to propose following classification for the stomata so the familiarwith the far recorded among monocotyledonous plants. Being more native ancient language Sanskrit, I have derived these terms from it (p. 664). 1 I. asahkoshik - (Aperigenous). These stomata are formed by direct 1 = = Sans: ‘A’ First letter of Devnagari Script; used to denote without - sahkoshika Asahkoshik = Without Subsidiary cell. (adj.) subsidiary cells, dwi = two + sahkoshik; = Six = chatur = four + sahkoshik; shat + sahkoshik; bahu Many 4- sahkoshik. Acta 801. Need. 18(5), Oct. 1969 655 G. S. PALIWAL divisions 1) 1) 1) 1) 1) ) of 1) 1) 1) 1) 1) 1) 1) 1) 1) 1) 1) 1) 1)1) 1) 1) (+ (+ (+ (+ (+ (+ (+ (+ (+ (+ (+ (+ (+ (+ (+ No. involved 2(+ K+ 4(+ variable variable 2(+ 6(+ 4(4-4(+l) 4(+l) 6(+ variable 2(+ variable 3(+ 3(+ 3(4- 2 1 1 4 2 6 4 6 3 3 3 1 2 1 3 subsi- ofsubsi- cells more of 2 diary or or No. 2 3-7 2-6 2 0 0 4 2 0 2 6 4 4 6 2 2 0 2 2 0 2 Haber (1960) & (1962); (1881);(1881); Jain (1866); Foard (1966) & Haber & 1962) Haber (1961) Campbell (1946); Stebbins (1960) (1960) Strasburger (1959; (1961) (1960); Northcote Khush (1866) (1866); Roy & Jain (1892) Jain (1966) (1937) (1937)(1937) Shah (1881) (unpublished) (unpublished) (unpublished) (1963) (1941); Stebbins & Moreland & & & Stebbins Moreland & (1965) (1948) & (1905); & & & Strasburger Strasburger Benecke & (1961) Picket-Heaps Author/s Stebbins Paliwal Shanks Strasburger Krauss Paliwal Paliwal Hamann Drawert Stebbins Strasburger Stebbins Porsch Tomlinson Porterfield Shah Riccharia Porterfield Flint Stebbins Campbell investigated lancasteri; Narcissus Z. communis sanguinea C. pubescens Monocotyledons. species ajax; aristata vulgaris quadrangularis offlcinarumojflcinarum vittata; sp., sp. vittata; umbellatusumbeiiatus vulgare vulgare and comosus pendulapendida generagenera in sp. edulis discolor saliva pseudonarcissus rosea mays stomata Genera Sagittaria Amaryllis Zephyranthes Z. Pathos Dieffenbachia Ananas Butomus Canna Centrolepis Commelina Rhoeo Tradescantia ZebrinaZebrina Several ArundinariaArundinaria Hordeum Oryza Phyllostachys Saccharum Triticum Pathos ~'* Zea of Ontogeny 1. Alismataceae Amaryllidaceae Araceae Bromeliaceae Butomaceae Cannaccae Centrolepidaceae Commelinaceae Gramineae Table Family 1. 2. 3. 4. 5.5. 6. 7. 8. 9. 656 Acta Bot. Need. 18(5), Oct. 1969 STOMATAL ONTOGENY AND PHYLOGENY I 1) 1) 1) 1) 1) 1) 1) 1) 1) 1) (+ K+(+ (+ (+ (+ (+ (+ (+ (+5(+ (+5(+ variable variable variable 1 3 1 1 1 1 1 5 1 1 3 1 1 1 5 more more or or 2-6 0 0 2 0 0 0 0 0 4 4 4 2 2- (1961) (1953); (1960); (1966) (1866) Khush Biegert Jain (1866) (1866) (1866) (1965) (unpublished) (unpublished) (unpublished) (unpublished) (unpublished) (unpublished) (1968) (1966) (unpublished) & & & & (1965) (1965) (1965) (1870) Kidwai Strasburger Strasburger Strasburger & Strasburger Paliwal StebbinsStebbins Paliwal BanningBiinning Stebbins ShanksShanks Paliwal Paliwal PaliwalPaliwal Shanks Shanks Paliwal Strasburger Inamdar Strasburger PfltzerPfitzer Tomlinson Pant Hamann Pandanus of capense chinensis zeylanica marginata species acorifolia glaberrimus lanuginosum candicans uniflorum graminifolius fasicularis pygmaea cepa barbadensis novoguineensisnovoguineensis Agrostocrinum porrum sativum Chlorophytum Hyacinthus Ornithogallum unnamed Belamcanda Juncus Allium Aloe Galtonia Ipheion Sanseviera Maranta Habenaria Orchis Pandanus Pandanus Helmholtzia Orthothylax Philydrum Philydrella Iris A. A. 4 H. IridaceaeIridaceae Juncaceae Liliaceae Marantaceae Orchidaceae Pandanaceae Philydraceae 10. 11. 12. 13. 14. 15. 16. Acta Bot. Need. 18(5), Oct. 1969 657 G. S. PALIWAL division of the meristemoid and are completely devoid of subsidiary cells; e.g. members of the Amaryllidaceae, Araceae, Liliaceae and Orchidaceae. In cotyledonary leaves of Oryza sativa a similar situation has been noticed by Richharia & Roy (1961). 2. dwisahkoshik - (Biperigenous). Such stomata are recognized by the of2 to the cells either presence subsidiary cells, placed laterally guard (one on side). The subsidiary cells owe their origin to the adjacent