ON THE MULTISEPTATE TRICHOSCLEREIDS IN THE SClNDAPSUS BY T. ANANDA RAO (Botanical Survey of India, 76, Lower Circular Road, Calcutta-14) Received February 25, 1964 (Communicated by Prof. L. Narayana Rao, r.A.sc.) THE thick sclerosed mechanical cells of Aroideae haye been termed Bast cells (Schleiden, 1839), Poils (Van Tieghem, 1867). Internal hairs (De Bary, 1884, p. 222), Trichoblasts (Sachs, 1882), Sclereiden (Francken, 1890) and Trichosclereids (Bloch, 1946). The existence of varied polymorphio sclereids is much responsible for the introduction of several terms to these curious cell forms. The sclereids stand in comparison with the fibres but differ from them in not forming a reticulum or compact strand and showing forking to form regular H-shaped forms.

The following flesh specimens were examined: 1. Scindapsus hederaceus Schott.. Singapore. 2. S. officinalis Schott. Sibpur, India. 3. S. perakenqs Hk. f. Perak. 4. S. pictus Hassk. Ahmedabad, India. 5. S. rupestris Ridl. Borneo. 6. S. scortechinii Hk. f. Malaya. 7. Scindapsus sp. Bombay, India. The reported occurrence of sclereids in Scindapsus spp. (Rao, 1953 and 1954) has been further studied in some of the available species with a view to elucidate salient features of sclereid distribution in the lamina. The sclereids form a conspicuous feature in the lamina, do not show any relationship with veins and veinlets and are idioblastically disposed amidst the tissue. They are more or less parallely disposed and in no instance were they found to form a reticulum or regular strand. The present survey of 7 species revealed the sclereid idioblasts of various forms. They are segre- gated under two types: Type L--Thick, fusiform, unbranched sclereids with fusoid ends. 66 On the Muhiseptate Trichosclereids in the Genus Scindapsus 67

Such cell forms are seen in Scindapsus scortechinii and S. officinalis. They have a thick striated wall and narrow lumen. Type//.--Thick fusiform, branching sclereids with fusoid ends. They are of varied forms. Most of them are Y- or H-shaped with many intergrading forms. Occasionally, the fusoid ends may fork and present curious cell form inside the lamina. Such cell forms are encountered in Scindapsus hederaceus (Figs. 1-5, 6), S. pictus (Fig. 8), S. perakensis, S. rupestris (Fig. 7) and Scindapsus sp. The sclereids are remarkable for their varied forms. They are mostly disposed in the form of idioblasts and are uniformly distributed inside the mesophyll. Their averag~ length is 1912.6/z and width is 77 "8 tz in S. hede- raceus whereas in S. officinalis the average length is 2648"9t, and average width is 62"2t* . The cell wall is striated and the lumen is of considerable irreguiar or uniform width as is often seen. The interesting features of these sclereids are the occurrence of septa (Figs. 1, 2) and forking to form regular H-shaped cell forms (Fig. 4). It is not uncommon to come across multi- septate sclereids as observed in S. hederaceus (Fig. 9). In addition, one can observe the existence of small crystals inside the lumen of enlarged sclereids. Systematics of Scindapsus Van Tiegham (1867) was the first to suggest the taxonomic interest of trichosclereids, a feature which was later on utilised by Engler (1876, 1878, 1879, 1884, 1920) in the systematic treatment of . The present study supports Engler's classification (1920) of the inclusion of the genus Scindapsus in the subfamily based upon tricho- sclereids. Recent studies of Nicolson (1960) have shown the presence of trichosclereids in thirty-two species of the Monsteroideae. Structural Aspects Sclereids range in form from fusiform to branched Y- or H- shaped types. It has been seen that within the limit of a single species as in Memecylon edule (Subramanyam and Rao, 1948) the polymorphism is very well exhibited. Recent researches have shown the abundance of poly- morphic sclereids and the importance of analysing them into definite groups within a certain range (Rao, 1957 a, b). In view of varied forms, sclereids have been designated differently by different workers (Rao, 1957 b). In spite of the development of different names to these thick-walled idioblasts the term 'sclereid' is maintained because 68 T. ANANDA RAO it is brief and etymologically clear and has much, therefore, to commend it (Eames and MacDaniels, 1947, pp. 88-89). Tschirch (1885, 1889) grouped the sclereids into four types based upon mature forms: brachysclereids, maorosclereids, osteosclereids and astrosolereids. In any attempt to segre- gate and identify the varied sclereids, one has to take into consideration the range of form variation in several species of the same genus (Foster, 1944; Rao, 1957 a) or same species from different habitats (Rao, 1953) or several genera of the same family or order. Rao (1957 b) has recognised on the basis of morphological data six main types of compact sclereid forms of wide occurrence in seed :

Spheroidal sclereids, osteosclereids, fusiform sclereids, filiform sclereids, astrosclereids and crystalliferous sclereids. The present study of trichosclereids especially of Scindapsus species has shown the existence of septate sclereids in the lamina. Majority of the investigated species have revealed that sclereids in spite of their form variation are unicellular and non-septate (Rao, 1953). However, multi- septate selereids of Scindapsus spp. and septate brachysclereids of Begonia corallina (Gertz, 1915) are distinct. The presence of septae constitute an important structural aspect in the morphology of sclereids.

SUMMARY

The present study has revealed the presence of Trichosclereids in seven spccies of Scindapsus. They form distinct idioblasts in the lamina. A note- worthy structural aspect is the presence of scptae in several sclereids.

REFERENCES

Bloch, R. .. "Differentiation and pattern in Monstera deliciosa. The idioblastic development of the trichosclereids in the air root," Amer. J. Bot., 1946, 33, 544-551.

De Bary, A. .. Comparative Anatomy of the Vegetative Organs of the Phenerogams and Ferns. Clarendon Press, Oxford, 1884. Eames, A. J, and Mac Daniels, An Introduction to Anatomy, McGraw-Hill Book Co., L.H. Inc., New York, 1947, 88-89. Engler, A. .. "Zur Morphologie der Araceae," Bot. Zeit., 1876, 34, 81-90, 97-105. .. "Araceae," in Martius, C.F.P. yon, Flora Brasiliensis, 1878, 3 (2), 26--244, Monachii, .. "Araceae," in De Candolle, A. and De Candolle, C. Mono- graphic Phanerogamarum, Parisiis, 1879, 2, 1-681. 1: Ananda Rao Proc. Ind. Acad. Sci., B, Vol. LX, Pl. II

FIGS. 1-5 T. Ananda Rao Proc. Ind. Acad. Sci., B, Vol. LX, Pl. 111

x

FIGS. 6-9 On the Multiseptate Trichosclereids in the Genus Scindapsus 69

Engler, A. .. "Beitriige zur Kematnis der Araceae V. 12. Uber den Entwickltmgsgang in der Familie der Araceen und uber die Bliitenmorphologie derselben," Bot. Jahrb., 1884, 5s 141-88, 287-336. .. Das Pflanzenreich. Heft. 74. Araceae Pars generalis et index famdiae generalis, W. Engelmann, Leipzig, 1920. Get tz, O. .. "Et fall of Septering hos KrJstalltorande Brachysklereider," Bot. Notiser, 1951, 149-58. Foster, A. S. .. "Structure and development of Sclereids in the petiole of Camellia japonica L.," Bull. Torrey Bot. Club, 1944, 71, 302-26.

Francken, C. J. W. .. Die Sclereiden. Diss. Utrecht, I890. Nicolson, Dan, H. ... "The occurrence of Trichosclereids in the Monsteroideae (Araceae)," Amer. J. Bot., 1960, 47, 598-602. Rao, T. A. .. "Studies on Foliar sclereids in seed plants," Ph.D. Thesis, Mysore University, 1953. .. "Nature and occurrence of septa in foliar selereids of Scindapsus,'" Curt. Sci., 1954, 23, 365-66. .. "Comparative morphology and ontogeny of foliar sclereids in ~ed plants, I. Memecylon L.," Phytomorphology, 1957a, 7, 306-30. "Comparative morphology and ontogeny of foliar selereids in seed plants," I1. Linociera Swartz," Proc. Nat. Inst. ScL lndia, 1957 b. Schleiden, M. J. .. "Botanische Notizen 5, Uber einige eigenthumliche Bastzellen,'" Arch. Naturg., 1839, 5, 231-34. Sachs, J. .. Text-Book of Botany, 1882, Oxford. Subtamanyam, K. and Rao, "Foliar selereids in some species of Memecylon," Proc. Ind. T.A. Acad. Sci., 1949, 30B, 291-98. Tsekitch, A. .. "Beitrage zur Kenntniss des mechanisehen Gewebsystemsf der pflanzen," Ber distch. Bot. Ges., 1885, 3, 73-75. .. Angewendte Pflanzenanatomie, 1889, Wien and Leipzig. Van Tieghem, P. .. "Recherches sur la structure des Aroidees," Ann. ScL Nat. Bot., Set. V., 1867, 6, 72-280.

EXPLANATION OF PLATES PLAT~ II FIGS. 1-5. Trichosclereids from the lamina of S. hederaeeus, × 100 each. PLATE lII

FIG. 6. Cleared lamina of S. hederaceus showing idioblastic disposition, × 50. Cleared lamina of S. rupestris showing the veinlet-end and trichoselereid, × 75. FIG. 7. FIG. 8. Cleared lamina of S. pictus as seen under polarised light, showing idioblastic disposition, x75. l:TIG, 9. A part of trichosclereid of S. hederaceus showing multiseptate aspect, x 100,