Hemigraphis and Strobilanthes

CUTICULAR STUDIES IN SOME SPECIES OF HEMIGRAPHIS AND STROBILANTHES

BY KHWAJA J. AHMAD (National Botanic Gardens, Lucknow-l, India) Received September 24, 1973 (Communicated by Dr. L. D. Kapoor, F.A.SC.)

ABSTRACT Cuticular investigations have been carried out in three species of IIemigraphis and nine of Strobilanthes. The two genera belonging to the family Acanthaceae are generally placed together within the same tribe by taxonomists. Hemigraphis and Strobilanthes show broadly similar epidermal characters though there are significant differences also. On the basis of the present study, the placement of these genera in two different sub-tribes but under the same tribe appears to be justified. The three species of Hemigrat-his show more or less uniform epidermal characters but H. colorata and H. hirta are more close to each other than to H. alternata. The epidermal characters of the investigated species of Strobilanthes, which fall within six of Bremekamp's new genera do not indicate any striking dissimilarities which would help to separate them under the new genera of Bremekamp. The variations recorded in the epidermal characters of different soecies of the two genera are sufficiently pronounced, as to justify their use in making distinctions at species level.

INTRODUCTION Hemigraphis Nees with about 100 species distributed over S. China, Indo- malaya, tropical Asia and Pacific is one of the largest genera of the family Acanthaceae. Strobilanthes Blume is represented by over 250 species chiefly distributed in tropical Asia and Madagascar. It is the largest genus of Acan- thaceae, and over 150 species are reported from India alone (Clarke, 1884- 85). Anderson (1867) recognised that Hemigraphis is not really distinct from Ruellia sensu Nees and he, therefore, transferred the bulk of the Ruellia species enumerated by Nees (1847) to Hemigraphis. Bremekamp (1944) on the other hand transferred some of the species fi'om Hemigraphis to several different genera. 29 30 KHWAIA J. AHMAD

Bremekamp (1944) using pollen morphology and other megascopic characters has split Strobilanthes into about two dozen genera. The present study, which deals with the foliar epidermis and cuticle of three species of tIemigraphis and nine of Strobilanthes (embracing six of Bremekamp's new genera) has been undertaken to supplement our present knowledge of the taxonomy of Hemigraphis and Strobilanthes.

MATERIALS AND METHODS The foliar material was either collected fresh locally (LUCK) or pro- cured as dried herbarium specimens from Dr. A. N. Rao, University of Singa- pore, Singapore (SING); Dr. K. C. Cheang, Waterfalls Gardens, Penang, Malaysia (MALAY); the Curator, Lembaga Biologi Nasional, Bogor, Indonesia (BOG); Mr. S. L. Kapoor, Parsari Farm, Chamoli, U.P., India (CHAMOL); the Regional Botanist, Botanical Survey of India, Western Circle, Poona (BSI-WEST) and Dr. P. V. Bole, Blatter Herbarium, St. Xavier's College, Bombay, India (BLATTER). The investigated species along with their source (in abbreviated form) are given below. In the case of the genus Strobilanthes, the generic equivalents of the investigated species given by Bremekamp (1944) are also provided. Hemigraphis alternata T. Anders. (SING); H. colorata Hall. f. (MALAY); H. hirta T. Anders. (LUCK); Strobilanthes alatus Wall. ex Nees --~ Pteracanthus alatus (Wall. ex Nees) Brem. (CHAMOL); S. barbatus Nees = NilgManthus barbatus (Nees) Brem. (BSI-WEST); S. callosus Nees---- Carvia callosa (Wall.) Brem. (BSI-WEST); 5;. crispus (L.) Blume ~- Serico- calyx crispus (L.) Brem. (BOG); S. heyneanus Nees----Nilgirianthus heyneanus (Nees)Brem. (LUCK); S. ixiocephalus Benth. = Thelepaepale ixio- cephala (Benth.) Brem. (BLATTER); S. pulneyensis Clarke =-Xenacanthus pulneyensis (Clarke) Brem. (BSI-WEST); S. scaber Nees = Sericocalyx scaber (Nees) Brem. (LUCK); S. scrobiculatus Dalz. (BLATTER). The cuticles were separated from leaves by mechanical peeling or by chemical maceration with 30-50~ nitric acid (Ahmad, 1972). The cuticles thus separated were mounted in pure glycerine and coverslips were ringed with Canada balsam. In the case of dried herbarium material, the leaves were first soaked in warm water before the maceration.

OBSERVATIONS The epidermal characters of three species of Hemigraphis and nine of Strobilanthes are described and these generic descriptions cover the main Cuticular Studies in some Species of Hemigraphis and Strobilanthes 31 characters of the species of those genera investigated. At the end of each generic description, a comparative table is given for the data on measurements of various epidermal characters, namely, epidermal cell size, stomatal size and frequency, glandular hair diaxneter and length (where long-stalked glandular hairs are present) and the length of non-glandular hairs. The length of the non-glandular hairs is expressed in the table (reading from left to right) as the minimum observed, the mean and the maximum observed length (Tables I arid II).

TABLE l Measurements ~ epidermal characters #1 Hemigraphis (L-- Lower epidermis : U = Upper epidermis)

Epid. Store. Store. G 1.h. Non-gl.h. Species cell freq. size diam. length (t~) (per mm 'z) (t~) (t~) (~) Hemigraphis L :57>:27 L :118 24:,. 15 25 110-167-205 alternata U : 54 ;< 39 tf. colorata L :68×33 L : 102 22×13 22 94-276--601 U :61;<36 U : 17 H. hirta L : 62×30 b : 113 23 ×13 24 50-204-490 U :67x42 U : 22

Epid. cell = Epidermal cell size ; Store. freq. = Stomatal frequenc3 ; Stom. size = Stomatal size; Gl.h. diam. = Diameter of glandular head; Non-gl.h. length = Length of non-glandular hairs.

Hemigraphis Nees Lower ej~idermis.--Intercostal cells polygonal or irregular, with straight. arcuate or slightly sinuous walls (Figs. 1, 3, 5). Costal cells polygonal to isodiametric in H. colorata (Fig. 30), much elongate in H hirta (Fig. 29) and H. alternata. Stomata diacytic, confined to intercostal areas. Stomata with single guard cell and with both the guard cells aborted rarely present in H. hirta.

Glandular hairs common, more numerous in the intercostal areas, subsessile; head globular, 4-8 celled (Figs. 22-28).

Non-glandular hairs (Figs. 7-14) common (sparse, restricted to the veins in H. alternata), 2-5 celled (often 1-celled in H. hirta), uniseriate, often stout; 32 KH-~CCAJA J. AHMAD

wall thin, ornamented with minutely elliptic tubercles (Fig. 15); poral rim circular, rarely polygonal; hair-base 2-several celled (often 1-celled in H. colorata and H. hirta).

TABLE II

Measurements of epidermal characters in Strobilanthes* (A =Average length of long-stalked glandular hairs)

Epid. Stom. Stom. Gl.h. Non-gl.h. Species cell freq. size diam. length Oz) (per mm 2) (tO (t~) (/~)

Strobilanthes L : 65 x37 L : 148 20xt2 25 118-283-637 alatus U : 64 x32 S. barbatus L : 55x32 L : 142 22x14 27 94-168-295 U : 58 ×33 S. callosus L :60x38 L : 96 25×16 26 94-200-354 U : 62 ×40 S. crispus L : 57 x 32 L : 148 24 x 15 25 55-195-460 U : 66x37 S. heyneanus L : 53 x25 L : 243 21 x13 27 635-932-1191 U : 57 x 33 750 (A) S. ixiocephalus L : 47 x25 L : t 56 25 x t 3 27 155-272-400 U : 52 x32 S. pulneyensis L : 52 x25 L : 160 20 x 13 25 236-613-1298 U : 55x36 S. scaber L : 61x34 L : 121 22x13 22 90-227-357 U : 46 x27 S. scrobiculatus L : 75x35 L : 80 29x17 34 175-340-550 U : 70 ×50

* Abbreviations explained in the footnote of Table I.

Cystoliths (Figs. 16-21) common, both in the costal and intercostal areas, simple, generally conical, cigar or sickle-shaped; double cystoliths rarely present (Fig. 20). Upper epidermis.--Intercostal cells polygonal or irregular, with arcuate or slightly sinuous walls (Figs. 2, 4, 6). Costal cells similar to those of the Cuticulap" Studies in some Species of Hemigraphis and Strobilanthes 33

I 2

FIOS, 1=30

Acad .--B 3 34. Km~t.AJA J. AHMAO

31 32

Fl~s. 31-53 Cuticular Studies in some ,Specias of Hemigraphis and Strobilanthes 35

54 55

56 57 73

58 59

/ 61

62 ~.~ 66 ~ 67

Flos. 54.-75 36 KHWAJA J. AHMAD lower epidermis. Stomata common, evenly distributed (H. colorata, H. hirta) or sparse and scattered along the vicinity of the veins (H. alternata). Glandular hairs, non-glandular hairs and cystoliths similar to those of the lower epidermis. In H. alternata, non-glandular hairs are absent on the upper epidermis.

Strobilanthes Blume Lower epidermis.--Intercostal cells polygonal, with straight, arcuate or slightly sinuous walls, in S. barbatus, S. crispus, S. ixioeephalus and S. serobiculatus (Figs. 33, 37, 54, 60); irregular and sinuous-walled in S. alatus, S. callosus and S. pulneyensis (Figs. 31, 35, 56). S. heyneanus and S. seaber (Figs. 39, 58) have intercostal cells variable in shape and sinuosity within the same species; they may be polygonal to irregular in shape with straight, arcuate or slightly sinuous anticlinal walls. Costal cells polygonal or elongate, arranged in rows (Figs. 52, 53). Stomata diacytic, confined to intercostal areas. Twin stomata present rarely in S. pulneyensis (Fig. 41). Glandular hairs (Figs. 42-50)common (rare on the veins), subsessile, with globular, 4-8 celled head. In S. heyneanus long-stalked glandular hairs with 3-4 celled stalk and 2 to several celled globular or hemispherical head occur rarely on the veins (Fig. 51). Non-glandular hairs (Figs. 68-74) common (sparse in S. ixiocephalus and 5;. serobieulatus, dense in S. callosus), generally restricted to the leaf mar- gin arid the veins; 1 to several celled, uniseriate, often stout; wall ornamented with tubercles (Fig. 75) ; poral rim circular or polygonal ; hair-base of 2 to several cells, often forming a ring around the foot of the hair. Cystoliths (Figs. 62-67) common, simple, generally sickle or cigar-shaped. often variable in shape. Double cystoliths occur rarely in S. barbatus and S. alatus (Fig. 64). Upper epidermis.--Intercostal cells polygonal, with straight, arcuate or slightly sinuous walls in S. barbatus, S. crispus, S. ixiocephalus, S. scaber and S. scrobiculatus (Figs. 34, 38, 55, 59, 61); irregular and sinuous-walled in S. alatus, S. callosus, S. heyneanus and S. pu!neyensis (Figs. 32, 36, 40, 57). Costal cells similar to those of the lower epidermis. Stomata absent (sparsely present in S. heyneanus and S. pulneyensis). Glandular hairs, non-glandular hairs and eystoliths similar to those of the lower epidermis, Cuticular Studies in some Species of Hemigraphis and Strobilanthes 37

DISCUSSION Nees (1847), Bentham and Hooker (1876) and Clarke (1884-85) clubbed Hemigraphis and Strobilanthes together in the tribe Ruellieae. Bentham and Hooker and Clarke also sub-divided Ruellieae into several sub-tribes but the former placed the genera within the same sub-tribe, Strobilantheae, while the latter assigned them to two different sub-tribes (Hemigraphis to sub-tribe Polyspermeae and Strobilanthes to Tetraspermeae). Lindau (1895) created an independent tribe Strobilantheae in which Hemigraphis and Stro- bilanthes are included. Bremekamp (1953, 1965) included the two genera in the sub-tribe Strobilantheae under the tribe Ruellieae, similar to what Bentham and Hooker had done. Hemigraphis and Strobilanthes show broad similarities in their epidermal characters such as intercostal and costal cells, glandular hairs, non-glandular hairs and cystoliths. There are, however, significant differences also; two out of three investigated species of Hemigraphis are amphistomatic (stomata sparsely present in third species also), while all the species of Strobi- lanthes are conspicuously hypostomatic. Non-glandular hairs are generally distributed all over the lower epidermis in Hemigraphis but in Strobilanthes they are usually confined to costal and marginal areas. Non-glandular hairs sometimes arise from a single epidermal cell in Hemigraphis colorata and H. hfl'ta but in Strobilanthes hair-base is always 2 to several celled. Fre- quently a ring of many polygonal cells is formed around the basal part of the hair. In view of the above facts, the assignment of Hemigraphis and Strobilanthes to two different sub-tribes within the same tribe as suggested by Clarke (1884-85) appears to be justified from the present study. The three species of the genus Hemigraphis presently examined show more or less uniform epidermal characters; the epidermal cells, glandular hairs, non-glandular hairs being more or less similar. The variations recorded in the epidermal characters of different species can serve to distinguish them from each other and are of great diagnostic value. H. colorata and H. hirta are more close to each other than to H. alternata. H. colorata and H. hirta are amphistomatic and the stomata are evenly distributed on the upper epidermis; in H. alternata the stomata on the upper epidermis are sparse and occur only along the veins. Non-glandular hairs in H. colorata and H. hirta occur both on the costal and intercostal areas, but in H. alternata they are restricted to costal areas of the lower epidermis, and they are absent on the upper epidermis. Small, slender, thread-like, 1 to 2-celled, non-glandular hairs are present in H. hfl'ta only. Acad.~B 4 38 KHWAJA J. AHMAD

A number of species formerly assigned to Ruellia have been transferred to Hemigraphis by Anderson (1867). According to Chauba! (1966) the pollen grains of the two genera are quite distinct. There are, however, no striking differences in epidermal characters between the two genera (Ahmad, 1972). Hemigraphis and Ruellia resemble each other in the shape of their cpidermal cells, glandular and non-glandular hairs and cystoliths, avd in both the genera amphistomatic as well as hypostomatic species are met with.

The species of Strobilanthes presently investigated fall broadly into two groups, namely, (i) species with polygonal epidermal cells and (ii) species with irregular epidermal cells. In S. hevneanus and S. scaber there is a transition between polygonal and irregular cells of the lower epidermis. S. scrobiculatus has polygonal, straight-walled intercostal cells which are larger than the epidermal cells of the other species. S. heyneanus and S. pulneyensis have non-glandular hairs of comparatively larger size than those in the other species;in S. hevneanus long-stalked glandular hairs are also present and the stomatal frequency is much higher than those in the other species (Table 11).

Bremekamp (1944) observed that the genus Strobilanthes Blume, as at present delimited, betrays its artiLciality by its wider range of variability and vague and disputable boundary line. He, therefore, split the genus into about two dozen genera (Bremekamp, 1944). The author examined the cuticle of nine species of Strobilanthes representing six of Bremekamp's genera, One of the examined species, 5;. scrobiculatus, has not been assigned by Breme- kamp to any of his new genera though it is suggested that it may be placed in Thelepaepale.

The epidermal characters of these species do not indicate any striking dissimilarities which would help to separate them under the new genera of Bremekamp. Their common features are: hypostomatic leaves, subsessile or short-stalked glandular hairs with globular, 4-8 celled head; and rather stout, uniseriate non-glandular hairs with a hair-base of 2-several polygonal cells and a broad pore. In most of the species the non-glandular hairs on the lower epidermis are restricted to the costal and marginal areas but on the upper epidermis they are common on intercostal areas also. The cystoliths are mostly simple, cigar-shaped or curved.

It is to be n0led that S/robilanthes is an eurypalynous genus. Vishnu- Mittre and Gupta (1966) observed that the shape of the pollen grains is not a Cuticular Studies in some Species of Hemigraphis and Strobilanthes 39 consistent character even for some of the genera (e.g., Pteracanthus and Nil- girianthus) created by Bremekamp. According to these authors (Vishnu- Mittre and Gupta, 1966, p. 306), "It is indeed difficult to comment on the delimitation by Bremekamp and to remark how far he has succeeded through the segregation of Strobilanthes Blume into several genera in raising it from an artificial status to a natural one." In Airy Shaw edition of Willis' Dictionary of the Flowering Plants and Ferns (1966) Strobilanthes B1. is retained as an undivided genus.

AC KNOWLED GEMENTS

I wish to express my gratitude and indebtedness to Dr. R. V. Sitholey, under whose guidance this work was completed• I am also thankful to Dr. P. K. K. Nair for some useful suggestions and to Mr. D. B. Shukla for help- ing me in the collection of material and preparation of slides. Part of the herbarium material required for this study was supplied to me by some orga- nizations and individuals (listed earlier under "Materials and Methods "). To them, my sincere thanks are due.

REFERENCES

Ahmad, K. J. "Cuticular studies in some Acanthaceae and SolanacCae," Ph.D. Thesis, Lucknow University, 1972•

Anderson, T. "An enumeration of the Indian species of Acanthaceae," J. Linn. Soc. (Bet.), 1867, 9, 425-56.

Bentham, G. and Genera Plantarum, Acanthaceae, 1876, 2, 1060-1122. Hooker, J. D.

Bremekamp, C. E. B. •. " Materials for a monograph of the Strobitanthinae (Acantha- ceae),'" Verb. Nederl. Akad. Wet. 2, 1944, Sect. 41, 1-306. •. "The delimitation of the Acanthaceae," Pivc. Koninkl. Nederl Akad. Wet. Amst., Set. C, 1953, 56, 533-46. .. "Delimitation and sub-division of the Acanthaceae," Bull. Bet. Surv. India, 1965, 7, 21-30.

Chaubal, P. D. .. Palynological Studies on the Family Acanthaceae, Univ. Poona, 1966.

Clarke, C. B. • . " Acanthaceae," Ill Hcoker, J.D., Flora of British India, 1884-85, 4, pp. 387-558•

Lindau, G. •. "Acanthaeeae," In Engler, A. and Prant[, K.• Die natiirlichen Pflanzenfamilien, 1895, 4, 274-354. 40 KHWAJA J. AHMAD

Nees Von Esenbeck, C. G. .. "Acanthacoao,"In De Candolle, A. P., Prodromus Syste- matis Naturalis Regni Vegetabilis, Paris• 1847, II, 46-519. Vishnu-Mittre and "Contribution to the pollen morphology of the genus Strobi- Gupta, H. P. lanthes Blume, with remarks on its taxonomy," Pollen et Spores, 1966, 8, 285-307. Willis, J. C. •. A Dictionary of the Flowering Plants and Ferns, Seventh Ed., Revised, H. K. Airy Shaw, Cambridge, 1966.

EXPLANATION OF FIGURES

FIGS. 1-30. Epidermal features of Hemigraphis. Figs. 1-6. Lcwer and upper epidermides (lower epidermides on the left and upper on the right. Figs. 1, 2. H. alternata. Figs. 3, 4. H. colorata; Figs. 5, 6. 1-[. hirta). Figs. 7-14. Nor,-glandular hairs (Figs. 7-10. H. cotorata; Figs. 11-13. H. hirta; Fig. 14. H. alternata). Fig. 15. H. hirta, portion of a non-glandular hair magnified to show wall ornamentation• Figs. 16-21. Cystoliths (Fig. 16. H. colorata; Figs. 17-19. H. altert.ata; Figs. 20,21. tLhirta). Figs. 22-28. Glandularhairs (Figs. 22-24. H. colorata; Figs. 25, 26. H. hirta; Figs. 27, 28. H. alternata). Figs. 29, 30. Costal cells (Fig. 29,• H. hirta; Fig. 30. H. colorata). Figs. 1-14, 16-21, 29, 30 (X 160); Figs. 15,22-28(x 360).

FIGS. 31-53. Epidermal features of Strobilanthes. Figs. 31-40. Lower and upper epidermides (lower epidermides on the left and upper on the right; Figs. 31, 32. S. alatus; Figs. 33,34. S. barbatus; Figs. 35,36. S. callosus; Figs. 37,38• S. crispus; Figs. 39,40. S. heyneanus). Fig. 41. S. puhwyensis, twin stomata. Figs. 42-50. Sub-sessile glandular hairs (Fig. 42. S. pulneyensis; Fig. 43. S. ixiocephalus; Fig• 44. S. heyneanus; Fig. 45. S. callosus; Fig. 46. S. crispus; Fig. 47. S. alatus; Fig. 48. S. barbatus; Fig. 49. S. seaber; Fig. 50. S. scrobiculatus). Fig. 51. S. heyneanus, long-stalked glavdular hair. Figs. 52, 53. Costal coils (Fig. 52. S. alatus; Fig. 53. S. barbatus). Figs. 31-40, 52, 53 (× 160); Figs. 41-50 (x 360); Fig. 51 (x 50).

FIGS. 54--75. Epidermal features of Strobilanthes. Figs. 54-61. Lower and upper epidermides (lower epidetmides on the left and upper on the right; Figs. 54, 55. S. ixiocephalus; Figs. 56, 57. S. pulneyensis; Figs. 58, 59. S. scaber; Figs. 60, 61. S. scrobiculatus). Figs. 62- 67. Cystoliths (Fig. 62. S. barbatus; Figs. 63, 64. S. alatus; Fig. 65. S. ixiocephalus, Figs. 66- 67. S. crispus). Figs. 68-74. Non-glandular hairs (Fig. 68. S. scaber; Fig. 69. S. scrobiculatus; Fig. 70. S. ixiocephalus; Fig. 71. S. crispus; Fig. 72. S. barbatus; Figs. 73, 74. S. caUosus)• Fig. 75. S. callosus, portio~ of a non-glandular hair magnified to show wall ornamentation, Figs. 54-74 (x 160); Fig. 75 (x 360).