IAWA Bulletin n.s., Vol. 7 (1),1986 47 STORIED STRUCTURE OF THE SECONDARY PHLOEM by R. W. den Outer Vakgroep Plantencytologie en -morfologie, Landbouwhogeschool, Arboretumlaan 4, 6703 BD Wageningen, The Netherlands Summary The anatomy of the secondary phloem with cambium the initials are not arranged in hori­ a storied structure of 49 species of woody dico­ zontal tiers, their ends overlap, they are long, tyledons from the Ivory Coast, West Africa, has and their length may vary considerably. The been studied. They belong to the families Bixa­ non-storied cambium is considered to be phylo­ ceae (I species), Bombacaceae (3 species), Cae­ genetically more primitive than the storied one. salpiniaceae (4 species), Papilionaceae (18 spe­ The storied pattern of fusiform cells can be dis­ cies), Sterculiaceae (16 species), and Tiliaceae rupted as a consequence of pseudo transverse di­ (7 species). In the Bixaceae and Sterculiaceae visions and elongation (Zagorska-Marek, 1984). only the axial system is storied whereas in the Both the axial cells and rays of secondary four other families usually both the ray and phloem and xylem derived from a storied cam­ axial systems are storied. bium may remain storied or the stratification Anatomical features accompanying storied may be present only in the axially elongated structure in the secondary phloem are describ­ cells. In this last case a partiy storied structure is ed, viz.: sieve-tube elements are generally short present. Within a species, even within a single with slightly oblique to transverse sieve plates; sample of a tree the storied structure can change sieve areas in the side walls of the sieve-tube from very conspicuous to hardly discernible. elements are sparse, poorly developed, unequal­ Therefore the development of storeys must be ly spaced or diffuse, or entirely absent; com­ dependent on several factors (Philipson et aI., panion cells are similar in length to the sieve­ 1971). tube elements they accompany, one per sieve A storied structure is usually accompanied by element or are septated to form a strand of other anatomical features in both the secondary cells; in the conducting secondary phloem, pa­ phloem and xylem. For the secondary xylem renchyma strands are nearly always composed they have already been described by J ansso­ of at the most four cells; phloem fibres, multi­ nius (1931), Reinders and Reinders-Gouwentak seriate rays and crystal cells are always present; (1961) and others in the following way: an arrangement of similar elements in tangen­ tial layers often occurs. Though storied struc­ I. fusiform parenchyma cells often occur; pa­ ture itself is considered to be an advanced fea­ renchyma strands are usually composed of ture, the component elements of the secondary only two cells, or at the most four cells (at a phloem itself can be specialised, intermediate distance of more than two cells from the ves­ or even primitive according to standards given sels); by Zahur (1959). 2. alllibriform fibres within a certain area of the Key words: Ivory Coast, sieve tubes, companion tree are approximately of the same length. cells, phloem parenchyma, phloem fibres, They have usually a wide middle part with phloem rays, evolutionary advancement. the length of the fusiform initials and sud­ denly narrowing pointed ends placed uni­ laterally on the middle part like a bayonet; Introduction 3. wood with storied structure lacks fibre­ The arrangement of cambial cells in tangen­ tracheids; tial view shows two basic patterns: storied and 4. perforation plates in the vessels are (usually) non-storied. In a storied (storeyed, stratified) simple; cambium the fusiform initials occur in horizon­ 5. when storied structure is present in one spe­ tal tiers with the ends of the cells of one tier cies of a family, one finds characteristics asso­ appearing at the same level. The initials are ciated with storied structure in all the other short, with little variation in length. They occur species of the same family. Conversely, if in highly specialised dicotyledons (Beyer, 1927; some species of a family possess these char­ Esau, 1977; Chavan & Shah, 1983; Metcalfe & acteristics, one can find species with actual Chalk, 1983, and others). In the non-storied storied structure in this family. Downloaded from Brill.com10/02/2021 07:10:07AM via free access ~ Table I. Secondary phloem characters of the investigated species with a storied structure. 00 sieve tube companion axial phloem cell parenchyma rays .... ':l'" --- --- 0 .... ",-0.... t::~'" C ~t:: ~E ..t:: E l:: '" "'-'" ::l~ E o<J2 C tOE t:: ~ ][ ;:';::1.. -0 ..". .:::t:: co place E '" '" ",.-""0 ",.-" t:: -t:: ::l "'- Ol '" '" ".... "'.- u ." "'- ~u"'~ 00.::: co ""-0 E~ B C co~ <l) co t:: .- <l) '" <l) <l) <l) <l) ~ .... 00 .... co Xu '"t:: '" ",-.... - > <l) .... Co <l) "'- co,- "'- '" t:: >~ '0 '"co Buxaceae c co_> '" E 0 t:: ~ >8 '" c * ** co '" ~ c Bixa orellana L. 692 III 235 c B + 290 4 + He I + Bombacaceae Adansonia digitata L. 301 III 420 b B + 490 4 He II + Bombax glabra (Pasq.) Robyns 401 III 470 b B + 490 8 + He II + Ceiba pentandra (L.) Gaertn. 161 III 295 b B + 380 8 + + Ho II + Caesalpiniaceae Dialium dinklagei Harms 258 II 250 b C + 320 2 + Ho II Distemonanthus benthamianus Baill. 811 III 290 b C + 320 4 + He II Griffonia simplicifolia (Yahl ex DC.) Baill. 614 III 320 b C + 320 7 + He I Piliostigma thonningii (Schum.) Milne-Redh. 292 III 190 c C + 200 4 Ho III + > Papilionaceae ~ Downloaded fromBrill.com10/02/2021 07:10:07AM Afrormosia laxiflora (Benth. ex Bak.) Harms 304 III 230 b C + 245 5 Ho II > 0:1 Baphia nitida Lodd. 47 III 230 b C + 260 2 Ho II E. Baphia spathacea Hook. f. 757 III 320 b C + 350 2 + Ho II ~ Dioclea reflexa Hook. f. 639 III 305 b C + 335 5 + + Ho I 5· Ery thrina cf. senegalensis DC. 419 III 205 b C + 190 2 Ho II + ::l Lonchocarpus griffonianus (Baill.) Dunn 722 III 175 b C + 190 2 + + Ho II ~ Lonchocarpus sericeus (Poir.) H. B. et K. 272 <: III 175 b C + 175 2 + Ho II + 0 Millettia lane-poolei Dunn 668 III 205 b C + 205 3 + + Ho II ,... Millettia lucens (Sc. Elliot) Dunn 233 III 220 b C + 205 3 + + Ho II --.J Millettia zechiana Harms 809 III 190 b C + 190 3 + Ho II :;-' via freeaccess Millettia spec. 807 III 220 b C + 220 2 + Ho II \Q Neorautancnia pseudopachyrhiza (Harms) Milne-Redh. 514 III 220 b 00 C + 230 2 Ho II 0\ ...... Ostryoderris stuhlmannii (Taub.) Dunn ex Harms 456 III 260 b C + 260 4 + Ho II > Platysepalum hirsutum (Dunn) Hepper 773 III 205 b C + 220 2 + + Ho II :IE Pterocarpus cf. mildbraedii Harms 216 II 390 b C + 390 4 + Ho II > Ho I t:l:l Pterocarpus santalinoides L'Her. ex DC. 104 & 487 III 220 b C + 275 2 + Eo Swartzia madagascariensis Desv. 421 III 205 b C + 230 4 + Ho II + lr S· Sterculiaceae ::s Cola buntingii Bak. f. 777 III 305 b B + 320 4 + + He II + i" Cola caricaefolia (G. Don) K. Schum. 546 III 360 b B + 390 4 + + He II + <: III b B 350 4 He II + Cola chlamydantha K. Schum. 676 230 + + + i2- Cola gigantea A. Chev. 299 III 290 b B + 305 4 + He II + -...l Cola cf. gigantea A. Chev. var. glabrescens Br. & Keay 498 III 320 b B + 320 4 + He II + Cola lateritia K. Schum. var. maciaudii (A. Chev.) Br. & Keay 697 III 320 b B + 350 4 + He II + ~ Cola laurifolia Mast. 362 III 245 b B + 260 4 + He II + 00 Cola millenii K. Schum. 331 III 335 b B + 350 4 + + He II + '"01 Cola nitida (Vent.) Schott & End!. 20 III 350 b B + 350 4 + He II + Cola reticulata A. Chev. 660 III 260 b C + 275 4 + He II + Heritiera utilis (Sprague) Sprague 781 III 290 b B + 290 4 + He II + Mansonia altissima (A. Chev.) A. Chev. 591 III 305 b B + 335 4 He II + Sterculia setigera De!. 340 III 335 b B + 350 4 + + He II + Sterculia tragacantha Lindley 336 III 360 b B + 375 6 + + Hell + Theobroma cacao L. 256 II 405 b B + 435 4 He II + Triplochiton scieroxylon K. Schum. 129 III 275 b C + 320 4 + He II + Tiliaceae Christiana africana DC. 214 III 305 b B + 305 4 He II + Desplatzia chrysochlamys (Mildbr. & Burret) Mildbr. & Burret 114 III 350 c B + 360 4 He II + Downloaded fromBrill.com10/02/2021 07:10:07AM Duboscia viridiflora (K. Schum.) Mildbr. 578 III 350 c B + 360 6 + He II + Grewia carpinifolia Juss. 289 III 260 c B + 275 4 + He II + Grewia malacocarpa Mast. 264 II 420 b B + 435 8 + + Hell + Grewia mollis Juss. 298 III 205 c B + 205 4 + He II + Nesogordonia papaverifera (A. Chev.) R. Capuron 243 III 305 c B + 305 4 + He II + Legend: + = present; - = absent. Sieve tube type I = sieve tubes over 500 J..UtIlong with very oblique sieve plates with 10 or more sieve areas, sieve pores small, diameter sieve tube about equal to that of parenchyma cells; type III = sieve tubes less than 300 J..UtIlong with slightly oblique to transverse, simple sieve plates, diameter less than that of parenchyma cell; type II = intermediate between types I and III. Sieve area type b = sieve areas present on side walls, poorly developed; type c =sieve areas absent from side walls or very obscure. Companion cell type B = cells as long as sieve tubes; type C =cells in septate strands; place * = companion cells parallel to the sieve tube against its ra- dial wall; ** = companion cells seemingly cut off from corner of sieve tube.