Proe. Indian Ac.ad. Sei. ( Sci.), Vot. 90, Number I, February 1981, pp. 31-43. ~~)'Printed in India.

Typology and taxonomic value of foliar sclereids in the 1. R. Br.

T ANANDA RAO* and SLLPI DAS Botanical Survey of India, Howrah 711 103, India * Present Address : 47/11, S¡ Mount Joy Ext~asiort, Hanumanthanai~ar, Bangalore 560 019, India

MS reccived 12 May 1979; revised 16 August 1980

Abstract. The present work has revealed that 32 out of 38 taxa of lsopogon possess variously shaped sclereids of diffuse pattem. Some species have grotes- quely mis-shapen selereids with thick waU and bhmt arras. They are designated as gnarlyform sclereids. Further, the taxonoraic probleras alluded to by Bentham are discussed in relation to the types of foliar sclereids.

Keywords. Foliar sclereids; typology ; lsopogon ; Proteaceae.

1. Introduetion

The genus Isopogon R. Br. is confmed to Western Australia and closely allied to Petrophile R. Br. Despite the reported oceurrence of selereids in a few speeies there is no detailed study on their typology and taxonomic value (Jonsson 1879; Solereder 1908; Metcalfe and Chalk 1950).

2. Materials and methods

The vouchered herbarium leal speeimens for this study were procured from diffe- rent herbaria, abbreviated in this paper following the symbols published by I-Iolmgren and Keuken (I974): Herbarium of the Komarov Botanjcal Institute of the Academy of Seienees of USSR (LE); National Herbarium of the New South Wales, Australia (NSW); Western National Herbarium (Perth), South Perth, Western Australia; Central National Herbarium (CAL), Botaaical Survoy of India, Sibpur, Howrah, India. The names of the t investigated ate listed in table 1. Leaves were cleared by the teehnique of Foster (1946) and unstained preparations were used for camera lucida drawings and photomierography.

31 32 T Ananda Rao and Silpi Das

Table I. Species of Isopogon investigated and referenr to ~lereid types.

Isopogon R. Br. (Bentham's Classification 1870)

Sdcr~d Taxa typcs

Sect. 1. Hypsamhus 1. 1. latifoliua R. Br. la. V. Mueller s.n. (Perth) P 2. I. euneatus R. Br. F. V. Mueller s.n. (LI]) P 3. I. ltnearis Meisn. Aplin and Coveny s.n. (NSW) G 4. I. polycephalus R. Br. J. W. Wrigley 5057 (NSW) OS 5. I. attenuatus R. Br. Preiss 653 (LE) OS 6. I. spherocephalus LindI. J. Drummond 559 (LE) G 7. L uncinatus R. Br. Preiss 756 (LE) G 8o L buxifolius R. Br. J. Drummond 395 (LE) P 9. var. obovatus R. Br. J. Drummond 396 (LE) P 10. var. spathulata R. Br. J. Drummond 249 (LE) P 11. L axillaris R. Br. Preiss 653 (LE) P 12. L tridens F. Muell. J. Drummond 170 (NSW) G 13. L baxteri R. Br. W. Baxter s.n. (NSW) P 14. L roseus Lindl. J. Drumraond 564 (LP.) G 15. I. culenanthoides Meisn. C. H. Githins 1690 (NSW) G

Seet. 2. Eustrobihts 16. 1. trilobus R. Br. Fischer s.n. (LE) G 17. L tripartitus R. Br. Preiss 668 (LE) G 18. 1. longifolius R. Br. Maiden s.n. (NSW) G 19. I. drummondii Benth. Maiden s.n. (LE) OS 20. L heterophyllous Meisn. Preiss 672 (LE) B&A 21. 1. villosus Meisn. Drummond 399 (LP.) A 22. L teretifolius R. Br. W¡ s. n. (NSW) R&O 23. L anethifolius (Salisb.) Knight, R. Coveny 2894 (LE) G 24. Lpetiolaris A. Cuna. N. S. Lander 272 (NSW) G 25. 1. anemonefolius (Salisb.) Knight, C. II. Githins 1690 (NSW) P 26, L ceratophyllus R. Br. T. J. Whaite 1455 (NSW) G 27. L asper R. Br. A. K. Eames s.n. (NSW), E. Pritzel 481 (CAL) G 28. L crithmifolius F. Muell. Drummond 563 (LP.) A 29. L formosus R. Br. Preiss s.n. (LE) OS 30. L divergens R. Br. Preiss 667 (LE) A 31. L scabriuscnlus Meisn. J. W. Wrigley s.n. (NSW) (3

UNCLASSlFmD TAXA 32. L dubius (K. Br.) Druce, Sonster 482 (NSW) G 33. L fletcherii 17. Muell, Boorman s.n. ('LP.) P 34. I. monoraifolius Me Gillivray, D.M.G. 2155 (NSW) A 35. L dawsoni R. T. Bak. S. Story 6840 {NSW) A 36. 1. prostratus Me Gillivray, Blaxell and Johnson, s.n. (NSW) G 37. I. pterophiloides R. Br. Preiss 680 (LE) P 38. L sp. s.L, s.n. (CAL)

Absence (A), Brachytracheoids (B), Sheathing cells (S), Khizo (K) and Or (O) Onarlyform (G), Ophittrosclereids (OS), PolyramoUs sclereids (P). Typology and taxonomy in Proteaceae 33 3. Observations

Studies on the ele leaves, hand seetions and macerations revealed that the mesophyll of 3 8 speeies of Isopogon possess the foUowing distnet features of some interest. The absence of selereids of any form were observed in the leaves of L crithmifolius, L dawsoni, L divergens, L heterophyllous, L monorifolius and L villosus. However, braehytraeheoids in /. heterophyllous and aelerotraeheoids in L villosus at the veia-endings were eompieuous and distinet in many of the speeimens examined. Sclereids of differeat forms aro obaea'ved in all the ~peeimons of 32 speeies asnong 38 speeies investigated, hore (tablo .1).

3.1. Typology Tho scleroids conforto to orto type and only in a few of the taxa examinod a rango of variations from onc typo into anothor is observo& Thoy cztegorisod into 5 ma• types : Rhizosclereids, Osteoscloreids, Gnarlyform sclercids, Ophiuro- scleroids and Polyramous scloroids. Somo dotailed foaturos of thcir typology are rocordcd below.

3.la. Rhizo and Oesteosclereids: Thoy aro encountered in the cylindrir lamina of I. tertifolius R. Br. (figures 1-3). Thoy forro a pseudo-l at the po¡ and individually they resomblo cither a rhizoseleroid or ostcoseloreid. The rooting portiorts of the rhizosclereids aro short and do not extend deeply into the mesophyll.

3 .lb. Gnarlyform sclereids: Small-sizod, mostly caeomorphie selereids, with thick sclerosed striatod cell-wall and lumon of irregular width in the centre eneountered in the lamina of L adenanthoides Moissn. (figure 4a), L asper R.Br., L ceratophyllus R. Br., L dubius (R. Br.) Druee, L longifolius R. Br., L linearis Meisn., L prostratus D. Me Gillv L roseus Lindi., L scabriusculus Meisn., L spherocephalus Lind. (figure 15), L tridens F. Muoll., L trilobus R. Br., L tripartitus R. Br. (figures 6, 7, 14), and L uncinatus R. Br. (figures 9, 12). Thesc mis-shapen scleroids exhibir diffusc pat'tern of surface distribution without any kind of positional relationship with the veins and vein-endings. Strueturally the selereids have relatively thiek striaXed w with a broad eentral lumen of irregular width whieh exteads into the short and blunt arras with round eads. The thick cell-walls have infrequenfly pits, both on the walls and lumen. In the laminae of a few species, n L anethefolius (Salisb.) Knight (figures 8, 16), L ceretophyllus R. Br. and L petiolaris A. Cuna., the gn sclereids aro rolatively bigger thart tho aforesaid short selereids and most of thom have contortod cell-body. In L tripartitus R. Br. a fow seloreids exhibit profusoly lobod eoll-body artd thus forro eonspieuous peculiar seloroids in the mid-mesophyll rogion of tho lamina (figures 6, 7). In L anethifolius (Salisb.) Knight (Coveny 2894, LE) the scloreids are eacomorphie with many erooked lobes (figuro 8).

3. lc. Ophiurosclereids : This category of seleroids aro eneountered in L atte- nuatus R. Br., L drummondii Bortth., L formosus R. Br. (figuro 4b) and L poly- cephaIus R. Br. Sclereids under this eatogory show extondod branches of unoqual length, somotimes a few of them aro eoilod. The scleroids have a rolativoly small 34 T Ananda Rao and Silpi Das

1

2

3

Figures 11-3. Isopogon tertifolius (Preiss, 668, LE). 1. Transeetion of tho eylindri- cal leal" showing peripheral disposition of rhizo and osteoselr (somi-diagrarn- mario). 2-3. A fcw maceratcd selcreids. Typology and taxonomy in Proteaceae 35

4o

1/

4b &

I. t 20o FL Figures 4--5. Chart showlng main typr of sclereids. 4a. Isopogon adenanthoidea (Gittins 1690, NSW) Gnarlyform sclercids. 4b. Isopogon formosus (Prciss s.n., LE) ophiuroselereids. 5. Isopogon axillari~ (Preiss 653, LE) Polyrarnous sclercids. central lumen which is very mueh oceludod in the centre. Structurally, thoy havo thick striated, pitted celt-wall and occluded lumen in the arras.

3 .Id. Polyramous sclereids: Selereids of this eategory ate observed in the lamina of L anemonifolius (Salisb.) Knight, L axillaris R. Br. (figure 17), L baxteri R. Br., L buxifolius R. Br., L buxifolius R. Br. var. spathulata Br,, L buxifolius R. Br. var. obovatus tL Br., L cuneatus R. Br., L fletcherª F. Mudl. (figures 10, 11, 13), L heterophyllous Moisn., L latifolius R. Br., L pterophiloides R. Br. artd L ap. (Aee. No. 390249, CAL). 36 T Ananda Rao aml Silpi Das

i1 ! ~

!V , B~

Figures 6-7. Isopogon tripartitus (Preiss 666, LE). 6. Transection of lamina with gnarlytbrm sclereids (semi.diagrammatie). 7. A few gnarlyform, sclereids; note the undulating or contorted outline of selereids. Typology and taxonomy in Proteaceae 37

): i

r'--- 9t o0t~

Figures 8-9. Transoctions of laminao showing gnarlyform scloreids. 8. (Coveny 2894, LE). 9. Isopogon uncinatus (Prr 788, LE).

Scloroids havo a contral body and oxhŸ many radiating oxtsndod arras in aU diroctions. The arma aro of unoqual length and ofton oxhibit pointod onds. In transcctions tltoy aro disposod in abundanco in tho mid-mosophyll rcgion with arras cxtonding closoly towards tho ad91 attd aba~xial portions of tho lamina. 38 T Ananda Rao and Silpi Das

A

-,.~ 91 91

l~gures IO-lI. Isopogon fletckerii (Conslable 6138, NSW). 10. Transecfions with polyramous sclereids (semi-diagrammatie). 11. A few polyramous selereids. Typology and taxonomy in Proteaceae 39

,, 1] __ I InIII III LI 89 -- ~ "

Figures 12-13. Photorticrographs of cleared la rfinae of: 12. Isopogon uneinatus (Preiss 758, LE) showing diffuse patterrt of G'~tar[yform sclereids. 13. lsopogon fletc•252 (Boorman s.n., LE) showing diffu5e pattern of polyramous sclereids. x 400 each. 40 T Ananda Rao and Silpi Das

J

17

Figures 14-17. Cleared laminae showing diffuse pattern of Gaarlyform sclereids. 14. lsopogon tripartitus (Preiss 666, LE). 15. [sopogon spherocephalus (Drummond 559, LE). 16. Isopogon anethifolius (Coveny 2894, LE). 17. Transectiort of lsopogon axillaris (Preiss 653, LE) showing polyramous sclereids. ;.: 400 each. Typotogy and taxonomy in Proteaceae 41 4. Taxonomical considerations [sopogon is one of the 14 goaera of the tribe Prote of the sub-f Nueamen- taee sensu Robort Brown (1910)or Porsoonioido sensu Engler (1894) whieh in modern sense following the intornational rulos of Bot Nomonel is altored to Proteoideae. Bontham (1870) has followod Robert Brown's el of Isopogon into two soctions, namely Hypsanthus Eustrobilus to sort out the thcn reeogaised 29 sp In tris study, ah attompt has beea mado to record the typology of seloreids found in the laminao of the studied t to assor their taxonomic or di value. 4.1. Morphological trends From the present study it is evident that thore aro stagos of differeatiation in the oecurrence of seleroids in the mesophylt. In the ¡ stago, there aro few taxa which aro devoid of selereids despite the f that the majority of tax exRibited selereids of diverso sliape and size in tris gonus. Howover, one eould see the oceurrenee of elustered terminal braehytraeheoids in a few of the selereid- less taxa. In the seeoRd stage, the selereids aro gnarlyform or sometimos erookedly lobod bodios fourtd scattered densely withia the mesophyll. In the third stage, the selereids aro of osteo- of rhizoseloroid types more of less loosely disposed in a row in the palis region. In the fourth stage, the seloroids r from ramiform to polyramous types often obsorved in dense disposition in the vieiaity of rnain veins. In the last stago, the polymorpRie selereids fiero eonspieuous idioblasts their arras radiate from the central body. Often they aro elosety set and giro a web-like Theso trends aro undoubtodly not of pkyletie bearing but ir is obvious that they aro refteeted iR the azsembled tax of both the seetions reeognised by Bentham (1870). Ir is of intcrest to remark that diffuse selereids faithfully present in the majority of the taxa of tris genus. Despito their oategorisation based on forro typos whjeh is hdpful for provisional idoatifie of speei~s or to nearby speeies, the corroer solution to be to resort to othor broad-b data from a wide rango of morphologieal fe including exomorpkiš endomorpRie features.

4.2. Taxonomic value One of the most interc~ting intern foaturc~ within the mcsophyU of the s191 specics of Isopogon is the oecutrence of varied typcs of sclereids of diffuse pattcrn. .SeveraI authors have emphasisod the importance of such calla in the provisional identification of vegetativo spccimens and also in solving problems of synonymy in the systematics of the studicd taxa. A fow of the striking interesting data in rotor to the foliar selereids of lsopogon aro presented below. The exomorpRie featuros of L polycephalus R. Br. L attenuatus R. Br. show great arnount of similarity. It is useful to record that in both the spoeie~, ophiuroscloreids ore oneoulxterod. This feature would be of intercat in the futuro atudies on the synonymy of the two spccies. L buxifolia R. Br. andits two varieties, namcly ver. spathulata R. Br. and ver. obovatus R. Br. show polyramous selcrcids with extended arras. In this opios eomplex Bentham (1870) has ereeted 4 varieties based on leal vaxiatio~ only. 42 T Ananda Rao and Silpi Das

In all probability the varietal status may not be tolerably distinct as supportod by the oceurreneo of similar types of selereids. L roseus Lindl. exhibits gnarlyform sclereids. This speeies has beett considered as synonymous with Petrophile dubia R. Br. In viow of this, ir is worthwhile to examino Petrophile dubia R. Br. whether the syrtonymy will hold good in respect of the typo of selereids. Bontham (1870) reports that L adenanthoides Meisn. r~ombles in its external aspeets Adenanthois near A. sericea or Petrophile inconspicus. In internal feature L adenanthoides exkibits spheroidal to sub-spheroidal or lobed selereids similar to that of A. sericea, t-Iowevor, in Petrophile inconspicus the lamina is devoid of sclereids (unpubti~hed). Isopogon trilobus R. Br. possesses fusiform and ramiform selereids with short arms Its synonymy with Petrophile trifida Lodd. could be confirmed in view of similar selereidal features (unpublished). Bentham (1870) writes "that L tripartitus R. Br. united by F. Mueller with 1. trilobus Meisn. seorns to pass rather moro gradually irtto L longifolius and aU the three might woll be considered az varieties of one species although in the. majority of specimens they appear very distinct ". From the standpoint of the typology of selereids, they are almost similar and thoreby support the eonterttion of Bentham that they can be regarded as varieties of one speeies. Bentham (1870) further eommenting on L longifolius R. Br. writes that " those specimens in whieh most of the teaves aro 3-1obed only differ from L tripartitus R. Br. in their greator lertgth. The infloreseenee, flowers and fruits aro the same as in L trilobus, L tripartitus, and I. longifolius "'. This viowpoint seems to be eorreet in view of the similarity of the sclereidal typology in all the three aforesaid speeies. I-Iowever, this needs eritieal study. Bentham's eommeat ora L drummondii Benth. that the foliage of this speeies is nearly that of Che undivided states of L teretifolius and L scabriuscula, with the former of whieh (the L petrophiloides Br.), ir may have been eonfounded by Meisaer, as he quotes Bexter's speeimens as well as Drummond's and Preiss's. From the standpoint of the typology of selereids differenees outweigh similarities. Ophiuroselereids aro eneountered in L drummondii whereas in L teretifolius the rhizo- and osteoselereids are observed. Thus the seloreids aro distiaet in the abovesaid speeies. The synonymy of L teretifolius R. Br. with L pterophiloides R. Br. seems to be not justified whon viewed from the types of seloreids that one would eneounter in them. In the former the selereids are of rhizo- and osteoselereids while in the lattor ir is of polymorphie type with extended arras. Thus they aro very distinet in thoir seleroid morphology. Bentham's (1870) statement that L petiolaris A. Cuna is nearly allied to L anemonifolius Kaight seems to be eorreet even in re~peet of the oeeurrenee of similar types of selereids in both the speei0s. Regaxding I. crithmifolius F. Muell., Bentham's (1870) statement that itis very elosely alliod to L formosus R. Br. seems to be not eorreet in respeet of selereid morphology. Ir has been fotmd that selereids ate absont in L crithmifolius whoroas in L formo~'us R. Br. ophiuroselereids are roeorded. Typology and taxonomy in Proteaceae 43

In the opinion of Bentham (1870) L scabriusculus Meisn. is in many respeets allied to L drummondii but the leaves are less terete, the parianth longer and more glabrous, although the cenes themselves are smaller. Foliar sclereids show different typ~ in both the species and their differenees outweigh similarities.

Acknowledgements

We thank the authorities of the Komarov Botanical Instituto, Leningrad, USSR, Nafional I-Ierbarium of the New South Wales, Australia, National Flerbarium, Sydney, Australia, aad Wostern National Flerbarium, Perth, Australia, for the gift of herbarium speeimens.

References

Beatham G 1870 Flora Australiensis (Lortdon : Lovell R.eeve artd Co.) Brown K 1910 Prodromas. florae Novae ttollandiae (Lortdon : J Johrtson) Bngler A 1894 Proteaceae in Die NaturL ; Pflanzenf. 3 119-156 Foster A S 1946 Coragarative morphology of the foliar sclereids in the germs Mouriria Aubl. ; J. Arnold Arb. 27 253-274 Holragren P K, and Keukea W 1974 The herbaria of the world, butex herbariorum, 6th ed. (Utreeht, Netherlands : Rega. Veg. 92) Jonsson B 1879 Bidrag till Kanrmdomen oro bladets anatomiska byggnad hos Proteaeeerna. Acta Unir. Lund. 15 1-54 Metcalfe C R artd Chalk L 1950 Anatomy of dicotyledons Vols. 1 and 2 (Oxford : Clarendon Press) R.ao T A and Bhupal O P 1973 Typology of sclereids ; Proc. Indian Acad. Sci. B77 41-55 Solereder I-I 1908 Systematic anatomy of the dicotyledons (Oxford : Clarendon Pross)