IAWA Bulletin n.s., Vol. 13 (I), 1992: 3-16 WOOD ANATOMY AND STEM OF CHLORANTHUS; SUMMARY OF WOOD ANATOMY OF CHLORANTHACEAE, WITH COMMENTS ON RELATIONSHIPS, VESSELLESSNESS, AND THE ORIGIN OF MONOCOTYLEDONS by Sherwin Carlquist Rancho Santa Ana Botanic Garden and Department ofBiology, Pomona College, Claremont,Califomia 91711 , U.S.A. Summary In contrast to the monopodial Ascarina and dicotyledons. While these cases are theoreti­ Hedyosmwn, Ch/oranthus and Sarcandra are cally possible, the histological and ecological sympodial. Sarcandra and Coerectus have seenarios that must be hypothesised for these woody canes of finite duration, whereas other events are ignored by cladists; most of these species of Ch/oranthus have shoots of one seenarios are unlikely for reasons explored year's duration ; these latter species have sec­ here, although a few are still worthy of con­ ond year wood only on rhizome s, not on up­ sideration. Stern endodermis is reported for right shoots. Rhizome portions transitional to three species of Ch/oranthus . upright sterns were selected for study. Chlo­ Key words: Ascarina, Chloranthaceae, Chlo­ ranthus erectus has abundant septate fibre­ ranthus , endodermis in sterns, Hedyos­ tracheids, C. jap onicus none, and two other mum, monocotyledon origins, Piperales, species a few. Ch/oranthus (and Sar candrai Sarcandra , vessel evolution, wood anat­ have rays of two distinct sizes in wood: rays omy . that are extensions of primary rays, and uni­ seriate and biseriate rays in fascicular areas. Introduction Wood anatomy of each of the four genera can be characterised, and is summarised in the The present study offers new data on wood form of a key. Except for primitiveness of anatomy of the genus Ch/oranthus. This pa­ vessels, wood of Chloranthaceae is very sim­ per is the fourth in a series that deals with ilar to that of Lactoridaceae and Piperaceae, wood of the family ; the other papers have and this probably indicates a close phyletic dealt with Sar candra (Carlquist 1987), As­ relationship. The large rays of chlorantha­ carina (Carlquist 1990), and Hedyosmwn ceous wood, little modified from prim ary (Carlquist 1992a). A summary of wood anat­ rays and with upright cells predominantly, are omy of the family is offered; other papers that indicative of some degree of herbaceousness have contributed to this summary are those of and some degree of secondary woodiness. Thierry (1912), Swamy & Bailey (1950), and Scattered bundles and multilacunar node s, Swamy (1953). characteristics of monocotyledons, are absent The inherent phylogenetic interest of CWo­ in Chloranthaceae but present in Piperaceae. ranthaceae is very great. The farnily has ethe­ The sympodial habit ofCh/oranthus and Sar­ real oil cells as well as other feature s that candra, and the presence of vessel s in roots place it unmistakably in Magnoliales sensu but not in sterns of Sarcandra are conditions lato (now superorder Magnoliidae of some like those basic to origin of monocotyledons. authors). However, the location of the farnily The possibility that Chloranthaceae are close within the order is not at all certain: several to Piperales and that these groups are close to recent treatment s consider it in a separate or­ origin of monocotyledons should be consid­ der (Chloranthaies) of the superorder Magno­ ered. Some cladists have hypothesised that liidae (e.g. , Lammers er al, 1986), which secondary vessellessness is polyphyletic in merely states the uncertainty of its relation- Downloaded from Brill.com10/07/2021 05:18:19AM via free access 4 IAWA Bulletin n.s., Vol. 13 (1), 1992 ships. Endress (1987), in a review of fea­ Whether vessellessness is primaryor sec­ tures of the family, cites more numerous ondary in particular dicotyledon phylads is an resemblances of Chloranthaceae to Hamame­ issue that has received comments in recent lidales, which lack ethereal oll cells and are years. For several reasons, Chloranthaceae are not placed in Magnoliidae, than to Laurales of pertinent in this regard, and a section of this Magnoliidae. Chloranthaceae have some high­ paper is devoted to a discussion of this matter. ly primitive features (e.g., wood) plus some Stern endodermis is reported here for three highly specialised features (floral structure). species ofChloranthus. This feature is SC8ICe Few will agree with Leroy's (1983) idea that in angiosperms, so occurrences are worthy of the inflorescences of Hedyosmum are actual­ being recorded. ly multistaminate primitive flowers (see the response to that idea by Endress 1987). The Materials and Methods phylogenetic problems posed by Chlorantha­ Stems and roots of ChJoranthus serratus ceae are not elose to solution at present, (Carlquist 15684 RSA) were collected in the The habit, wood, and vascular bundles of forest of Mt. Unzen, Kyushu, Japan, in 1982 Chloranthus in particular, and Chloranthaceae and preserved in formalin-acetic-alcohol. The in general, contain features relevant to con­ kindness of Prof. Mikio Ono in aiding my sideration with respect to origin of mono­ field work is gratefully acknowledged. Mate ­ cotyledons. Although Chloranthaceae have rial of other species of Chloranthus was de­ not been considered elose to origin of mono­ rived from herbarium specimens: C. erectus cotyledons because of such features as their (Stone 12116 KLU), Templer Park, Selangor, rather specialised flowers, opposite leaves, Malaysia; C. japonicus (Gorovoy 8 June and cylindrical arrangement of bundles, the 1968 RSA),N of the River Komarovka, family is definitely worthy of consideration in Primorye Terr., Siberia, USSR; C. multi­ this respect. Features ancestral to origin of stachys (Sino-American Botanical Expedition monocotyledons include sympodial growth 1185 RSA). habit, short-lived upright stems, minimal cam­ Stems of Chloranthus erectus were boiled bial activity, wide primary rays , and vessels in water, stored in 50% aqueous ethyl alco­ in roots only (tracheids only in other organs): hol, and sectioned on a sliding microtome. these are features of Sarcandra (and, except for Sections for study by SEM were dried be­ distribution of vessels, Ch/oranthus). Trim­ tween clean glass slides. Material of C. ser­ ery, basic to flowers of monocotyledons, is ratus was infiltrated, embedded in paraffin evident in flowers of Chloranthaceae (female and sectioned. Material of C. japonicus and flowers of Hedyosmum have three tepals ). C. multistachys was from herbarium speci­ Chloranthaceae have a range of habits: mens and was treated with 2% NaOH to ex­ Ascarina and Hedyosmum are monopodial pand tissues, then stored in 50% aqueous shrubs to trees, whereas Chloranthus and Sar­ ethyl alcohol, infiltrated, embedded in paraf­ candra have a sympodial growth form; Sar­ fin, and sectioned. Sections of all species candra, C. erectus, and C. spicatus have up­ were stained with a safranin-fast green com­ right shoots that last for several years and can bination. Paraffin seetions for SEM study branch somewhat, whereas the remaining were mounted on aluminum stubs followed species of Chloranthus form upright stems by removal of paraffin by means of xylene. that last only a single year. This range of habits Macerations of all species were prepared by is obviously of interest with respect to wood means of Jeffrey's fluid and stained with anatomy, An attempt is made here to charac­ safranin. terise the wood of the species and genera stud­ Terms used are according to the IAWA ied. In this regard, the reader should be aware Committee on Nomenclature (1964). Primary that species names commonly encountered in wall presence in perforations is referred to as Chloranthus and Sarcandra have been sup­ membraneremnants (Carlquist 1992b). Vessel planted in accord with the studies ofVerdcourt diameter is taken as lumen diameter at widest (1985). A synonymy is offered in the Materi­ point. In scanning a section with the light mi­ als and Methods section. croscope to determine vessels per mm -, ray Downloaded from Brill.com10/07/2021 05:18:19AM via free access Carlquist - Anatomy of Chloranthus 5 areas were not excluded (but only secondary nonstoried. Starch present in ray cells and xylem was included). occasionally in septate fibres. The species names in Chloranthus and Chloranthus japonicus (Figs. 12-15). Sarcandra are according to Verdcourt (1984, Wood diffuse-porous (Fig. 12), although the 1985): Chloranihus erectus (Buch.-Ham .) second year's wood (on rhizomes and bases Verdcourt (= C. ofjicinalis Blume); C.japo­ of upright stems) has smaller vessels, often nicus Siebold; C. multistachys Pei; C. serra­ irregular in shape and size (Fig. 15, left third tus Roem & Schult; Sarcandra chloranthoi­ of photograph), whereas the first year's ves­ des Gardner (= S. irvingbaileyi Swamy); S. sels are arranged in orderly rows (Fig. 12). glabra (Thunb.) Nakai [= C. brachystachys Vessels at the end of first year wood are nar­ Blume, S. hainanensis (Pei) Swamy & Bai­ rower and more tracheid-like (Fig. 14, mid­ ley]. Sarcandra thus consists of two species; dle); some may actually be tracheids. During Chloranthus, which has not been monograph­ the second year's growth (Fig. 14, top), wider ed as a genus, contains about 10. vessels are intermixed with narrower vessels; narrower vessels bear scalariform end wall pitting typical of wider vessels (Fig. 15). Anatomical descriptions of wood Vessels as seen in transection in large groups Chloranthus erectus(Figs. l-ll). Diffuse­ by virtue of absence of imperforate tracheary porous (Fig. 1). Vessels mostly solitary (Fig. elements. Mean vessel diameter, 33 um . 1); mean number ofvessels per group, 1.15. Mean vessel wall thickness, 2.2 um. Mean Mean diameter of vessels, 32 lUD. Mean num­ vessel element length, 1188 um. Perforation ber of vessels per mm-, 107. Mean vessel plates all scalariform (Fig. 20). Mean number wall thickness, 2.0 lUD. Mean vessel element of bars per plate, 76. Lateral wall pitting of length, 1207 um, Perforation plates scalari­ vessels transitional, opposite, or alternate. form (Fig. 6), mean number of bars, 78. Axial parenchyma not present in the ordinary Membrane remnants in perforations varying sense; parenchyma cells between vessels in from extensive (Fig.