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  • Author or Editor: Sherwin Carlquist x

Sherwin Carlquist

In contrast to the monopodial Ascarina and Hedyosmwn, Chloranthus and Sarcandra are sympodial. Sarcandra and C. erectus have woody canes of finite duration, whereas other species of Chloranthus have shoots of one year's duration ; these latter species have second year wood only on rhizome s, not on upright shoots. Rhizome portions transitional to upright sterns were selected for study. Chloranthus erectus has abundant septate fibretracheids, C. japonicus none, and two other species a few. Chloranthus (and Sarcandra) have rays of two distinct sizes in wood: rays that are extensions of primary rays, and uniseriate and biseriate rays in fascicular areas . Wood anatomy of each of the four genera can be characterised, and is summarised in the form of a key. Except for primitiveness of vessels, wood of Chloranthaceae is very similar to that of Lactoridaceae and Piperaceae, and this probably indicates a close phyletic relationship. The large rays of chloranthaceous wood, little modified from primary rays and with upright cells predominantly , are indicative of some degree of herbaceousness and some degree of secondary woodiness. Scattered bundles and multilacunar nodes, characteristics of monocotyledons, are absent in Chloranthaceae but present in Piperaceae. The sympodial habit of Chloranthus and Sarcandra, and the presence of vessel s in roots but not in sterns of Sarcandra are conditions like those basic to origin of monocotyledons. The possibility that Chloranthaceae are close to Piperales and that these groups are close to origin of monocotyledons should be considered. Some cladists have hypothesised that secondary vessellessness is polyphyletic in dicotyledons. While these cases are theoretically possible, the histological and ecological seenarios that must be hypothesised for these events are ignored by cladists; most of these seenarios are unlikely for reasons explored here, although a few are still worthy of consideration. Stern endodermis is reported for three species of Chloranthus.

Sherwin Carlquist

Qualitative and quantitative data are given for two species of Rhabdodendron. Newly reported for wood of the family are vestured pits in vessels and tracheids, nonbordered perforation plates, abaxial axial parenchyma, and presence of sphaerocrystals. Although treated variously in phylogenetic schemes, Rhabdodendron is placed in an expanded Caryophyllales in recent cladograms based on molecular data. This placement is consistent with features characteristic of most families of the order, such as nonbordered perforation plates and successive cambia. Primitive character states in Rhabdodendron (tracheids, diffuse axial parenchyma, ray type) are shared with Caryophyllales s.l. that branch near the base of the clade: Agdestis, Barbeuia, Simmondsia, and Stegnosperma. Presence of vestured pits in vessels and silica bodies in wood, features not reported elsewhere in Caryophyllales s.l., are shared by Rhabdodendron and Polygonaceae. Wood of Rhabdodendron has no features not found in other Caryophyllales, and is especially similar to genera regarded as closely related to it in recent phylogenetic hypotheses. Successive cambia that are presumably primitive in the clade that includes Rhabdodendron are discussed. Distinctions between sphaerocrystals and druses are offered.

Sherwin Carlquist

Wood and bark anatomy are described for four species of three genera of Caricaceae; both root and stem material were available for Jacaratia hassleriana. Wood of all species lacks libriform fibers in secondary xylem, and has axial parenchyma instead. Cylicomorpha parviflora has paratracheal parenchyma cells with thin lignified walls; otherwise, all cell walls of secondary xylem in Caricaceae except those of vessels have only primary walls. Vessels have alternate laterally elongate (pseudoscalariform) pits on vessel-vessel interfaces, but wide, minimally bordered scalariform pits on vessel-parenchyma contacts. Laticifers occur commonly in tangential plates in fascicular secondary xylem, and rarely in xylem rays. Proliferation of axial parenchyma by zones of tangential divisions is newly reported for the family. Bark is diverse in the species, although some features (e.g., druses) are common to all. Wood of Caricaceae is compared to that of two species of Moringaceae, recently designated the sister family of Caricaceae. Although the wood and bark of Moringa oleifera, a treelike species, differ from those of Caricaceae, wood and bark of the stem succulent M. hildebrandtii, the habit of which resembles those in Caricaceae, simulate wood and bark of Caricaceae closely. Counterparts to laticifers in Moringaceae are uncertain, however. Phloem fibers of Caricaceae form an expansible peripheral cylinder of mechanical tissue that correlates with the stem succulence of most species of Caricaceae.

Sherwin Carlquist

Petiveria and Rivina have been placed by various authors close to each other within Phytolaccaceae; widely separated from each other but both within Phytolaccaceae; and within a segregate family (Rivinaceae) but still within the order Caryophyllales. Wood of these monotypic genera proves to be alike in salient qualitative and even quantitative features, including presence of a second cambium, vessel morphology and pit size, nonbordered perforation plates, vasicentric axial parenchyma type, fiber-tracheids with vestigially bordered pits and starch contents, narrow multiseriate rays plus a few uniseriate rays, ray cells predominantly upright and with thin lignified walls and starch content, and presence of both large styloids and packets of coarse raphides in secondary phloem. Although further data are desirable, wood and stern data do not strongly support separation of Petiveria and Rivina from Phytolaccaceae. Quantitative wood features correspond to the short-lived perennial habit ofboth genera, and are indicative ofaxeromorphic wood pattern.

Sherwin Carlquist

Qualitative and quantitative data are given for wood anatomy of three species of Pentaphragma (Pentaphragmataceae); the woods of the three species are very similar. Pentaphragma is rayless, but eventually develops rays in at least one of the species studied. This is interpreted as related to secondary woodiness or upright habit within a predominantly herbaceous phylad. The vessel elements of Pentaphragma have features universally interpreted as primitive in dicotyledons: scalariform perforation plates with numerous bars; pit membrane remnants in perforations; scalariform lateral wall pitting; the genus also has fiber-tracheids with prominently bordered pits. These character states accord with the basal position in Campanulales accorded Pentaphragmataceae by Cosner et al. (1992), and suggests that order may have begun with more numerous primitive features than generally recognized. The presence of occasional scalariform perforation plates, often aberrant, in secondary xylem of families of Asterales sensu lato - Campanulaceae, Pentaphragmataceae, Valerianaceae, and even Asteraceae (e.g., certain Lactuceae) - can be attributed to paedomorphosis, extending these plates into secondary xylem from primary xylem. Raylessness in Pentaphragma can be described in terms of secondary woodiness or paedomorphosis. The fact that fiber-tracheids are shorter than vessel elements in Pentaphragma is believed related to raylessness also, because some fiber-tracheids are produced from 'potential' ray areas.

Sherwin Carlquist

Wood of Aristolochiaceae has vessels with simple petforation plates; lateral wall pitting of vessels alternate to scalariform; tracheids, fibre-tracheids or libriform fibres present; axial parenchyma diffuse, diffuse-in-aggregates, scanty vasicentric, and banded apotracheal; rays wide and tall, paedomorphic, multiseriate only, little altered during ontogeny (new rays originate suddenly as wid~ multiseriate rays); ethereal oil cells present in rays; wood structure storied. All of these features occur in Lactoridaceae and Piperaceae, and support the grouping of Aristolochiaceae with these families and the nonwoody family Saururaceae. Chloranthaceae may be the family next closest to this assemblage. Druses characteristically occur in rays of Aristolochia. Tracheids in Aristolochia may be correlated with the lianoid habit, although Holostylis, a caudex perennial thought close to Aristolochia, also has tracheids. The fibre-tracheids and libriform fibres of Apama and Thottea may be related to the sympodial shrubby habit of those two genera. On the basis of one species each of Apama and Thottea, the genera differ with respect to wood anatomy. The paedomorphic ray structure of all genera of Aristolochiaceae suggests an herbaceous or minimally woody ancestry rather than ancestors with typically woody monopodial habit. Types of bark structure observed in the species surveyed are briefly characterised. Storied wood structure and presence of druses and ethereal oil cells in rays are newly reported for the family.

Sherwin Carlquist

Sherwin Carlquist

Wood and bark histology data on stems of two species of Stegnospenna (Stegnospermataceae, or Phytolaccaceae s.l.) is presented, complementing previous accounts . Wood of Stegnosperma is relatively primitive within Caryophyllales because of presence of tracheids , diffuse parenchyma, and both multiseriate and uniseriate rays . The solitary nature of vessels is held to be correlated with tracheid presence , as in other groups of dicotyledons with vessels solitary or nearly so. Bark anatomy is newly reported for the genus . The method of section used permits analysis of divisions in cells with primary walls. Radial rows of parenchyma ('secondary cortex') develop in the inner cortex and are perpetuated by tangential divisions collectively termed a diffuse lateral meristem here. Successive cambia form within the radial rows of parenchyma. Despite diverse terminology and interpretations in literature on plants with successive cambia, the successive cambia and their origin in Stegnosperma are believed to represent the same anatomical phenomena as in other Phytolaccaceae s.l.