Made in United States of America Reprinted from BRrrroNlk Vol. 19, No. 2, April—June, 1967 pp. 99—121 ANATOMY AND SYSTEMATICS OF (SENSU LATO)

SHERWIN CARLQuIsT

Cariquist, S. (Rancho Santa Ana Botanic Garden, Claremont, Calif.) Anatomy and Systematics of Dendroseris (sensu lato). Brittonia 19: 99—121. 1967.—Ana tomical study of the Dendroseris (Compositae: ), endemic to the Juan Fernandez Islands, was undertaken to determine if segregate genera were valid. Other questions include the significance of pith bundles and of receptacular bristles, and whether the ancestors of these peculiar rosette trees and shrubs were woody or herbaceous. Anatomical evidence, when added to that from gross morphology, suggests that the segregation as distinct genera of Rea, Phoenicoseris, and Hesperoseris is probably not justified, and that they are better treated as subgenera of Dendroseris. Differences in pollen morphology, floral trichomes, achene and leaf anatomy provide good species characteristics. These all appear, respectively, as variations on a basic plan, and Dendroseris can be envisaged as derived from a common stock in the Juan Fernandez Islands. The genus is not particularly primitive within the family or tribe. The presence of additional bundles in the flowers of D. litoralis may be interpreted as related to gigantism. The separate corolla lobes in D. gigantea probably do not represent a vestige of an actinomorphic condition. Pith bundles in Dendroseris may have been present in ancestors; in any case, they seem likely to have increased in prominence with increase in stem diameter. Available evidence seems to favor the interpretation of growth forms in Dendroseris as derived from an herbaceous ancestry.

INTRODUCTION The genus Dendroseris (Compositae, tribe Cichorieae), is an endemic of the Juan Fernandez Islands, Chile. This genus has attracted attention because of its range of peculiar growth forms. Sparsely branched rosette trees, palmiform rosette trees, and succulent rosette shrubs are prominently represented. The species of Dendroseris are among the woodiest of the tribe Cichorieae, a tribe notable for woody genera on islands almost exclusively: (Desventuradas Islands, Chile), Munzo thamnus (San Clemente Island, California), and sect. Dendrosonchus (Canary Islands) are conspicuous among these. I have been interested in the anatomy of Dendroseris because of the possibility that anatomical studies will elucidate the phylogeny and relationships of this genus and its peculiar growth forms. Although Skottsberg (1956, p. 361) averred that Dendroseris and other Juan Fernandez rosette trees are relicts, the opposing view, stated by Darwin (1859), has been the one which seems supported by recent comparative investigations. The genus Dendroseris is worthy of comparative anatomical study for other reasons. The diversity of form within the genus is great, and although Skottsberg (1922) regarded it as a single genus, he later (1951) decided to recognize four genera: Dendroseris, Rca, Phoenicoseris, and Hesperoseris. Skottsberg’s decision in favor of the segregate genera was influenced by Erdtman’s (1952) work on pollen (also sum marized in Skottsberg, 1951). Are the differences in pollen morphology wide enough to warrant recognition of segregate genera, or are they in reality variations on a single basic pattern? Study of anatomical features is needed to support or refute segregate genera. With regard to other considerations, Dendroseris contains excellent examples of loss of dispersibility (Carlquist, 1966). This phenomenon has so far been described only in terms of gross morphology; anatomical study can reveal the underlying basis of this evolutionary tendency. This study was inspired by material provided directly and indirectly by the late Dr. Carl Skottsberg. He provided me in 1956 with an excellent collection of liquid

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FIGs. 1 3 F G. 1. Dendroseris mic,antha. Longisectiori of shoot apex, bowing natuie of leaf prirnordia and trichornes. F&. 2. Dendro ens rnicrcsntha Transection of prirnar) tern, bowing two phloern strands in pith. Fic. 3. Dendroseris macrophylla. Portion of leaf transection, showin midvein in upper larnina. daxial face at iight FIG. 1, 3, X 102, Fin,. 2, >< 145. 1967 CARLQUIST I DENDROSERIS 101 preserved Juan Fernandez Cornpositae. This material was the basis for my earlier studies on Centaurodendron and Yunquea (1958), and is permitting similar studies on Robinsonia, Rhetinodendron. and Symphyochaeta. Dried specimens were sent to me by Dr. Skottsberg, and other specimens collected by him also were used in the present study. For the sake of simplicity, the taxonomic conclusions of this study may he given here so that the nomenclature of the species mentioned can reflect those conclusions. Anatomical studies do show certain characters which might be used to support segregate genera. Indeed, any anatomical study is likely to demonstrate more char acters than were known before such a study. However, I am impressed with the fact that all expressions, either in gross morphology or anatomy, point to the likelihood that in Dendroseris we are dealing with variations on a single basic pat tern. In oth’er words, this evidence does not conflict with a hypothesis that the Juan Fernandez Cichorieae all stem from a single ancestral stock. The diversity within Dendroseris is indeed remarkable, but recognition as a single genus, in ac cordance with Stebbins (1953), emphasizes the adaptive radiation which has occurred, an adaptive radiation paralleling that of other insular genera. These considerations appear to me to override the convenience of using segregated genera. Indeed, I would like to use the names of segregate genera as a means of referring to natural groupings within Dendroseris. I followed this practice earlier (1960, 1965, 1966), as did Kunkel (1957) and Skottsberg (1953). However, the goals of ap pear better served by use of the following scheme: Subg. Dendroseris: D. litoralis, B. macrant/ia, D. macrophylla, D. marginata. Subg. Schizoglossum’: D. gigantea. Subg. Phoenicoseris Skottsb.: D. berteriana, B. pinnata, B. regia. Subg. Rca (Bert.) Skottsb.: D. inicrantha, D. neriifolia, D. pruinata. Only D. gigantea. D. macrophylla, and D. regia occur on Más Afuera, where they are endemic. The remainder are endemic to Más a Tierra or islets offshore from Más a Tierra. Floristic information on Dendroseris has been given by Skottsberg (1922, 1929, 1951). Data on ecology are offered by Skottsberg (1928, 1953) and Kunkel (1957), and Skottsberg (1956) has reached phytogeographical conclusions about Dendroseris. Illustrations of habit or morphological details of Dendroseris may be found in all of these papers, as well as in Carlquist (1965, 1066). Wood anatomy of the Juan Fernandez Cichorieae has been surveyed earlier (Carlquist, 1960), and con sequently data are not included here.

MATERIALS AND METHODS

The specimens upon which studies were based are listed below. Specimens listed from Stockholm (S) document the liquid-preserved portions sent me by Dr. Skotts berg. Specimens from American herbaria provided portions which were treated in order to provide anatomical preparations. In addition to the kindness of Dr. Skottsberg, who provided dried collections (RSA) in addition to the liquid-preserved specimens, I would like to acknowledge the generosity of the curators of the U.S. National Herbarium. Dendroseris berteriana (Dcne.)Hook. & Am.: Skottsberg 28-11-1955 (S); D. gigantea Johow: Skottsberg 436 (RSA): D. litoralis Skottsb.: Skottsberg 30-X11- 1954, vegetative (5): Skottsberg 3-111-1954, floral (S); D. macrant/ia (Bert. &

Dendroseris subgenus Schiog1ossum (Skottsberg) Cariquist, comb. nov. Rea sect. Schizo glossum Skottsb., Nat. Hist. Juan Fernandez and Easter Island 2: 201. 1922. Hesperoseris Skottsberg, Nat. Hist. Juan Fernandez and Easter Island 2: 788. 1951. 102 BRITTONIA jVOL. 19

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9( FIGs, 4—9. . Sections of stem and petiole to show vascularization. FIG. 4. Stem, petiole, and portion of leaf blade, disassembled to show venation features. Fins. 5—7. En larged portions of leaf midvein, middle region of petiole, and basal portion of petiole, respectively. Xylem shown in black, phloem unpatterned, collenchyma stippled. Fin. 8. Radial longisection of stem, showing vasculature associated with three nodes. Note pith bundles. FIn. 9. Transection. Further explanation in text. FIG. 4, X 1.2; FIGs. 5—7. X 5.5; Fin. 8, X 1.4; Fin. 9, X 1.6. 19671 CARLQUIST: DENDROSERIS 103

Dcne.)Skottsb.: Skottsberg 330 (RSA); D. macrophylla D. Don: Skottsberg 12-11- 1955 (S); Skottsberg 362, floral (US); D. marginata (Bert. & Dcne.)Hook. & Am.: Skottsberg 3-XII-1916 (US); D. micrantha Hook. & Am.: Skottsberg 20-111-1955, vegetative (S); Skottsberg 567, floral (RSA); D. pinnata (Bert. & Dcne.)Hook. & Am.: Skottsberg 5-111-1955, vegetative (5) H. Weber in 1937, floral (RSA) D. pruinata (Johow)Skottsb.: Skottsberg 20-111-1955, vegetative (S); Shottsberg 79, floral (US); D. regia Skottsb.: Skottsberg 570, vegetative (RSA). No material of D. neriifolia was studied. Dendroseris regia has been collected sterile only. Fully mature achenes are apparently not known in D. gigantea, D. macrant/ia, nor D. inacrophylla. The fixation of liquid-preserved material proved suitable for all but embryological studies. Conventional methods were used for preparing paraffin sections, which were mounted and stained with a safranin—fast green combination, corresponding to Northen’s modification of Foster’s tannic acid—ferric chloride method (Johansen, 1940). Dried material for anatomical studies was treated with 2.5% aqueous NaOH to expand tissues and to clear. Portions were then embedded, sectioned, and stained according to the above techniques. These sections provided reliable, if sometimes unattractive, preparations. Other portions of the NaOH-treated material were prepared as whole mounts, using safranin as a stain and Canada balsam as a mounting medium. This technique also was employed for pollen grains. Sections of pollen grains proved useful, and these were prepared according to the usual paraffin techniques: sections 5—6 thick of pollen-containing flowers were obtained.

ANATOMICAL DESCRIPTIONS

Vascularization of the Shoot. In Figs. 1—16 are shown details of vascular bundles and their arrangement in stems and leaves. The complexity of vasculariza tion seems related to the large size of stems and leaves. The pith region widens out markedly only a short distance below the shoot apex (Fig. 1). In all species of Dendroseris, vascularization is present in pith. This takes the form of bundles which contain phloem only, as in D. inicrantha (Fig. 2), or both xylem and phloem. as in D. litoralis (Figs. 4, 8, 9). Stem material was available for D. berteriana, D. lit oralis, D. macrophylla, D. micrantha, and D. pruinata. Of these, only D. litoralis has vessel elements and libriform fibers in pith bundles of the stem. The remainder have phloem bundles only. In D. herteriana, xylem was observed in bundles of pith of the axis, however. In all cases, the pith vascularization takes the form of transverse plates related to nodes (Figs. 8, 9, 14). These plates are open networks in which bundles join and diverge in various patterns (Figs. 9, 15). From this network, bundles may run from one plate to the one above and below (Figs. 8, 14). In addition, the periphery of the pith contains many vertical bundles (Figs. 2, 8, 9, 14, 15). Some of these are phloem strands which are very small and have been omitted from the drawings. Bundles do not run from one plate to the next if a species contains transverse pith diaphragms (each containing one or two plates of vascularization) separated by transverse pockets of air. Dendroseris berteriana has such pith diaphragms; pith is “hollow” according to Skottsberg (1951) in subg. Dendroseris and Piwenicoseris, and presumably such pith diaphragms as observed in my material of D. berteriana are meant. In the cortex of sterns, numerous leaf traces are ordinarily visible, because nodes are multilacunar and crowded. How are leaf traces and the bundles of the vascular cylinder of the stem related to the pith bundles? As far as can be determined, the cylinder bundles are collateral, not bicollateral, in structure, although bicollateral bundles are characteristic of petioles and major veins of leaves (Figs. 3, 5—7, 11—13). In D. litoralis, plates of pith bundles are clearly related to bundles of the vascular 104 BRITTONIA [VOL. 19

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Fins. 10—16. Dendroseyjs micrantha. Sections of stem and petiole to show vascularization. Conventions as in Figs. 4—9. Fm. 10. Stem, petiole, and portion of leaf blade, disassembled to show venation features. FIGs. 11—13. Enlarged portions of petiole, midrib of lower leaf, midrib midway along leaf, corresponding to sections, as indicated by gaps, in Fig. 10. Fm. 14. Radial longisection of stem, showing vascularization relating to four nodes. Fm. 15. Transection, show ing pith bundles and leaf traces. Fm. 16. Four successive stages in the departure of a leaf trace. A pair of bundles other than the leaf trace is shown in each stage. Relationship between a strand of phloem in the pith (first stage) and internal phloem of the leaf trace (stage at far right) is indicated. Fm. 10, X 1.8; Fins. 11—13, X 6.8; Fm. 14, X 1.8; Fin. 15, )< 2.0; Fm. 16, X 6.8. 1967] CARLQUIST: DENDROSERIS 105 cylinder at nodal regions At the same levels at which some bundles extend outward as leaf traces, other traces turn inward to vascularize the pith (Fig. 8, upper right). In other cases, phloem strands from the pith can be seen to extend outward through the leaf gaps (Fig. 9, below) and enter the petioles as phloem strands on the upper faces of petiolar bundles (Fig. 8, lower right, middle left). This is also true in D. micrantha (Figs. 15, 16). In addition, strands of phloem from bundles adjacent to the leaf gap may contribute phloem to the adaxial side of a leaf trace (Fig. 16). Leaf traces depart as a simple arc, which may be seen at the lowest levels of the petiole. Further out (Fig. 13), additional bundles are evident. These form a conspicuous upper series in the petiole, as in Fig. 7. Such upper bundles are mostly inverted or otherwise abnormally oriented. Ontogenetic studies of apical meristems showed that these additional bundles are the product of an adaxial meristem. Such a meristem can be seen in the bulging adaxial portions of leaf primordia such as those shown in Fig. 1. The additional bundles join the normal set in the lower petiole. Multiplication of bundles in the normally oriented set occurs by ordinary divarications (such a branching is shown in Fig. 13). The supernumerary bundles increase in prominence distally along the petiole (Figs. 6, 12) and both normal and supernumerary bundles are seen in the midribs of leaves (Figs. 3, 5, 11). Not all the supernumerary bundles have both xylem and phioem. Many are merely phloem strands (Figs. 3, 5—7, 12—13). Some phloem strands are associated with the adaxial faces of bundles, which thereby become bicollateral. Part of these phloem strands enter the petiole from the stem in the ways indicated above in connection with pith bundles. Others arise de novo in the petiole. Bundles inverted in orientation are limited to petiole, midrib, and secondary veins in the leaf. Smaller veins in the lamina are entirely normal in orientation. This results from the fact that inverted bundles alter in orientation as they diverge from main veins into the lamina. The significance of pith bundles in Cichorieae has bewildered various workers. For example, Worsdell (1919) considered them as vestiges of a formerly more com plete and complex vascularization. This hypothesis, although appealing in its directness, is not supported by any evidence which could not just as easily be interpreted in the reverse fashion. Moreover, one would ultimately have to invent an explanation for the origin of such a complex vascularization from the normal dicotyledonous pattern in ancestors of Cichorieae. If one compares the systematic occurrence of pith bundles in Cichorieae (cf. Metcalfe & Chalk, 1950) to a phylogenetic classification of the tribe (Stebbins, 1953), one notes that the occurrence of pith bundles characterizes genera at every level of phylogenetic specialization. The abundance of pith bundles in the Juan Fernandez Cichorieae is almost in direct proportion to the diameter of the pith. Conditions like those of the Juan Fernandez Cichorieae were reported by Worsdell in several genera—Tragopogon, for example. More instances could doubtless be uncovered. Complex nodal vascularization of this sort occurs in genera of other tribes of Cornpositae as well (Worsdell, 1919; Davis, 1961). While no purpose would be served by attempting to use the limited data of the present study as a basis for an all-inclusive hypothesis, one may note the correlation in Dendroseris between occurrence of pith bundles and both width of pith and rel atively poor secondary growth. Cichorieae are notable among Compositae in their lack of secondary growth, and vascularization of pith regions might compensate for paucity in secondary xylem conducting elements. Another possibility is a relation ship to the broad, multilacunar nodal regions characteristic of Cich’orieae. The fact that the above correlations are not perfect in all groups in angiosperms at large does not alter the possibility that in particular groups these factors might be operative.

of lamina, Section 24. Fin pruinata. enir Dendro Fins. 24—25. pole. phloem the below just is

a laticifer in vein; xylem above are visible 22; fibers in left Fig. at of shown vein Enlargement

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20. Fm. Portion gigantea. Dendroceris 20—21 Fios. secondarie. the of one is right at ein The

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Dendroseris laticifers. are right at and left mesophyll in streaks Dark litoralis.

18. Fin. Dendroseric rnacrophvlla Dendrmeri Fin. 17. leaes. of Sections 1/—25 FIGs.

25 24

IVOL. 19 106 BRITTONIA 19671 CARLQTJIST: DENDROSERIS 107

Stem Histology. Stems of Dendroseris offer few complexities other than those of vascularization. Noteworthy is the presence of a stem endodermis. This is evident in the occurrence of a prominent Casparian strip, which is identical to that reported in Fitchia (Carlquist, 1957) and other Cornpositae. There are no protophloem fibers in Dendroseris, so the endodermis is located directly outside protophloem sieve tubes. Pith and cortex consist of thin-walled parenchyma almost exclusively. Lignifica tion can be seen at the periphery of the pith in some old stems of Dendroseris. Periderm activity is evident on older stems. The products are cork exclusively, except on leaf scar areas, where 2--4 layers of brachysclereids were observed to comprise the phelloderm. In D. berteriana, which has pith diaphragms, meristematic activity could be seen in pith of old sterns. Divisions of pith parenchyma cells tend to expand the diaphragms, widening them so as to narrow the transverse air spaces between the diaphragms. Such divisions often tend to mimic rib meristem activity. Where pith diaphragms come into contact with each other as a result of this activity, some pith cells tend to develop into thin-walled brachysclereids. Both pith and cortex are rich in laticifers. Most laticifers are closely associated with phloern. For example, the wider cells in the phloern strands in Fig. 2 are laticifers. In addition, laticifers not associated with phloem are abundant. Such laticifers occur as packets of cells often, identifiable by their narrowness in transection as compared to pith parenchyma cells (Fig. 2, top, to right of center), and in longisection by their continuous tubular forms. Laticifers are all of the articulated anastomosing type. Petiole Histology. Petioles are parenchymatous, but collenchyma bands are conspicuous. Collenchyma bands near the lower surfaces of petioles characterize D. litoralis (Figs. 6, 7). In species with smaller leaves (Figs. 12, 13), such collenchyma is absent or less conspicuous. In all species, small collenchyma strands adjacent to phloem poles of bundles may be seen (Figs. 6, 7, 12. 13). Collenchyma was not observed where petioles meet stems. In a few species (D. macro ph’vlla, Fig. 3: D. pinnata) fibers are present adjacent to the xylem or phloem poles of bundles in petioles and leaf midribs. Collenchyrna is conspicuous in the midribs of leaves (Fig. 3). Laticifers are mostly confined to the periphery of phloem, as in the large bundle of Fig. 3. Lamina Histology. The species and subgenera of Dendroseris show considerable distinctness with regard to lamina histology, and may be discussed with regard to taxonomic groupings. In subg. Dendroseris, D. macrophylla (Fig. 17) has notably thin leaves. Hy podermis is absent in many areas, and is chiefly present near bundle-sheath extensions. Bundle-sheath extensions occur on most veins. About two layers of palisade and five of spongy parenchyma are present. Air spaces are prominent in spongy tissue. Dendroseris litoralis (Fig. 18), on the other hand, has thick leaves. Epidermal cells are large; external walls are thick. One layer of hypodermis is universally present. Two layers of hypodermis occur in many locations. Bundle-sheath extensions are present only on larger veins; most veins lack them. Larger veins have bicollateral bundles. About four layers of palisade cells and seven to nine of spongy cells are characteristic. Mesophyll cells are relatively closely arranged, with small inter-

showing a single vein. FIG. 25. Paradermal section taken from near leaf margin, showing group of cells (left) in which cells have marked lignified thickenings facing a space. A pair of cells, lower right, are developing such thickenings. Fics. 17—20, 22, 24, X 67; Fins. 21, 23, 25, )< 122. 108 BRITTONIA VOL. 19

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Fins. 26—33. Floral venation in Dendroseris. Fins. 26—28. Dendroseris litoralis. Fit;. 26. Vena tion of an entire flower; adaxial edge of flower, upper portion of ligule turned so as to be seen in face view. Outlines of flower in narrow lines, veins in wider lines. Style and stamen traces are typical for Compositac and have been omitted . Similar conventions apply to other drawings. Fin. 27. Achenc, showing five-veined condition. Fin. 28. Enlarged portion of corolla throat, 1967 CARLQUIST: DhNDROSEIUS 109

cellular spaces. Although laticifers “wandering” in mesophyll occur in all species of Dendroseris, they are especially conspicuous in D. litoralis. The leaves of D. macrantha (Fig. 19) and D. marginata are essentially identical, in these two species, leaves are relatively thick. A single hypodermis layer is universally present. Bundle- sheath extensions are present on almost all veins. About four palisade and seven spongy layers are present. The fact that leaves of D. macrophylla are thin and have large air spaces and little hypodermis seems related to the occurrence of these in shady forest habitats. Contrasting conditions in D. litoralis would connote the open sunny low land habitats that species inhabits. Variations in constitution of mesophyll with rela tion to sun or shade may be expected in these and other Dendroseris species. The sole species of subg. Schizoglossum, D. gigantea (Figs. 20, 21) has notably thin leaves. A single hypodermis layer is present. On virtually all veins, bundle- sheath extensions occur. About two palisade and five spongy layers are present. On the ahaxial epidermis, uniseriate non-glandular trichomes may be found (Fig. 21). These trichomes are essentially the same as those which occur on corolla-lobe tips in this species (Fig. 36). In subg. Phoenicose;is, D. pinnata (Figs. 22, 23) and D. regia are alike in leaf anatomy. A single hypodermis layer is present; bundle-sheath extensions are pres ent on larger veins only. On larger veins (about half the veins observed), one or a few fibers are present above the xylem pole. Major veins are bicollateral. Leaves of D. berterZana conform to the same pattern, but bicollateral bundles were not observed. About three layers of palisade and six of spongy tissue characterize species in subg. Phoenicoseris. In subg. .Rea, leaves are exceptionally thick. The pattern is the same for both D. pruinata (Fig. 24) antI D. micrantha. Beneath the epidermis is a single layer of large hypodermis cells. Bundle-sheath extensions characterize the majority of veins. About five layers of palisade and six to eight of spongy tissue are present. The term “palisade” has been used above despite the fact that these cells are nearly isodiarnetric in shape. Trichomes are mentioned above only for D. gigantea. The difference between this species and the others is merely one of preservation of trichomes into the mature leaves. As one might expect, leaf primordia of all species bear uniseriate non-glandular trichomes, as shown for D. micrantha (Fig. 1). No glandular trichomes were observed in Dendroseris. In all species examined, peculiar sclereids were observed in leaf mesophyll, as shown in Fig. 25. These sclereids differ from normal ones in having thickenings only on walls facing similarly thickened walls. Layering is conspicuous in the thickenings. These sclereids occur in small or large nests, in various portions of the epidermis and mesophyll. Their patterns of thickening appear as a response to an injury. Their distribution in the leaf also suggests this. Kunkel’s (1957) report of galls in the same position—near leaf margins—in D. pinnata as I have observed in all species confirms the interpretation that these sclereid nests are pathological in origin. Secondary Xylem. Wood anatomy of the Juan Fernandez Cichorieae has been analyzed earlier (Cariquist, 1960). Additional comments here are unnecessary.

showing the anomalous girdle of bundles and veinlets which extend short distances above and below this girdle. FiG. 29. Dendroseris macrantha. Tip of corolla. FIG. 30. Dendroscris largi nata. Tip of corolla. Fic. 31. Dendroseris pinnata. Venation of entire flower. Fic. 32. Den droseris gigantea. Venation of entire flower. Fin. 33. Dendroseris pruinaia. Venation of entire flower. 1 cm scale applies to Figs. 26, 27, 29, 30. 5 mm scale applies to Figs. 31, 32, 33. 2 mm scales applies to Fig. 28. 110 BRITTONIA 1V0L. 19

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FIGs. 34—50. FIGs. 34—38. Tips of corolla lobes, viewed from exterior surface, to show trichomes and sclereids. Heavy lines indicate sclerification; epidermal relief is indicated on cells at tips of lobes. FIG. 34. Dendroseris macrophylla. FIG. 35. Dendroseris litoralis. FIG. 36. Dendroseris gigantea. Fxc. 37. Dendroseris pinnata. FIG. 38. Dendroseris pruina.ta. Fsos. 39—43. Surfaces of corolla tubes (edge at left in each) showing trichomes. FIG. 39. Dendroseris macrantha. Fin. 40. Dendroseris rnacrophylla. FIG. 41. Dendroseris gigantea. FIG. 42. Dendroseris pinnafa. FIG. 43. Dendroseris pruinata. FIGS. 44—50. Views of pollen grains. One of the three colpi and germ 19671 CARLQUIsT: DENDROSERIS 111

Involuere. The writer noted earlier (1966) that in Dendroseris loss of dis persibility is not merely a matter of achene morphology, but extends to the nature of involucres as well. The anatomical features basic to this phenomenon are worthy of investigation. Involucral bracts in D. berteriana (Fig. 51) open out somewhEt at maturity, mostly at the tips. Tn Fig. 51 are seen the central portion of an intermediate bract (left), the lateral portion of an outer bract (right). These bracts are essentially mature. Ground tissue of the bracts is parenchyma, although the large cells (center) have lightly lignified walls which would offer a modest degree of rigidity. A few epidermal cells on the inner faces of bracts of D. berteriana have lignified thickenings. In involucres of most Compositae, the mechanism for reflexing of bracts is a fibrous inner bract face coupled with a parenchymatous outer face; when the latter dries and shrinks, the bract turns outward. In D. berteriana, this scheme is poorly fulfilled, for the inner face is not strongly rigid, and in some bracts sclerenchyma in the outer face of the bract would hinder shrinkage, so that the bract would tend to remain in the same position as when it was fresh. In subg. Dendroseris, the broad involucres containing large fruits are completely enfolded by the bracts when heads dry. This behavior is understandable when bract anatomy is studied. In D. litoralis (Fig. 52), ground tissue of bracts is exclusively thin-walled parenchyma, except for some suggestion of collenchymatous thickenings. Collenchyma does not influence bract rigidity appreciably upon drying. Thus, bracts have no mechanism to insure their folding outward when an involucre matures and dries. Lacking sclerenchyma, bracts can weather and fray easily, how ever, so that achenes would eventually be released. In D. micrantha (Fig. 53), bracts have an anatomy similar to those of D. litoralis, although they are much thinner. Mature bracts of D. micrantha have relatively thin-walled cells exclusively; some cells suggest lignification of walls in their staining reactions. All bracts in Dendroseris have only a single arc of collateral bundles, although additional phloem strands are present in larger bracts. Laticifers are notably wide and prominent in involucral bracts, and a number may be seen (especially adjacent to phloem poles of bundles) in Figs. 51—53. In subg. Dendroseris, receptacles of heads bear conspicuous bristles; they are present, but much smaller, in subg. Phoenicoseris. In D. litoralis (Fig. 63, right), these bristles are large, terete, and of various lengths. No vascularization was ob served, although presence of laticifers was established in larger bristles, and associa tion of a few laticifers with sieve tubes would not he unexpected. Cells of receptacular bristles remain thin-walled and no lignification was observed. Th’e function of receptacular bristles in Dendroseris is not evident. They do not seem to aid dis persal—in fact, one might imagine that they would hinder it. Their form and anatomy does not suggest that they are vestiges of true receptacular bracts. They may (in subg. Dendroseris. at least) be a by-product of the gigantism so evident in the species in which these bristles are conspicuous. Floral Venation. The venation of flowers in Dendroseris is basically that desig nated “Cichorieae—simplified” in a phylogenetic summary of floral venation of

pores shown in center of each of the entire grains. In sections of pollen grain walls (from microtome sections), spines and stratification of exine are shown. Intine indicated by line at bottom, nexine by densely stippled strip, sexine by more sparsely stippled area. FiGs. 44—45. Dendroseris litoralis. FiGs. 46—47. Dendroseris pinnata. “Para-apertural depression” shown at left in Fig. 47. Fin. 48. Dendroseris gigantea. Fins. 49—50. Dendroseris prisinata. Scales of magni fication apply to all figures within the horizontal rows in which they occur. 112 BRITTOI\IA 1V0L. 19

• .

.- b4•J

-.ti

49j 4

J 1 ‘f± - . rc - vc i5

55 56

f GS. 1 56. Fius. 51—53. Transections of inlolucral bract , outer faces at iight. FIG. 51 Dendro e;i berteriana. T o successic bracts shown. FIG. 52. Dendroseri.s 1itorali. FIG. 5. Dendroseris niirantha. FIGs. 54— 6. Section of mature achenes. FIGs. 54—55. Dendroseric inzcrantha FIG. 54. TranSection of achene a em is present at the angle, above, but at the inside face 01 the ss’all, not in the fiber . FIG. 55. Lonisection of achene, showing folds in 1967] CARLQUIST: DENDPOSERIS 113

Compositae (Carlquist, 1961). Deviations from this pattern in Dendroseris include presence of additional corolla bundles—particularly at tips of corolla lobes, and in the corolla throat. In each style branch there is only a single vein and thus a pair of veins in the undivided portion of the style. Stamens contain a single trace each; each stamen trace parallels a corolla vein, joining it at the base of the corolla tube. In .D. litoralis (Fig. 26), there are basically five veins in the corolla tube, four or five (Fig. 27) in the achene. At the base of the achene, more than a single vein connects with receptacle venation—a fact which probably is related to the large size of achenes in subg. Dendroseris, for the other subgenera have only a single vascular bundle connecting achene to receptacle. The ovule trace, however, is un branched despite the large size of the ovule; the trace outlines the odd, broad tri angular shape of the ovule, a shape which foreshadows the large, wide embryo. Den droseris litoralis has markedly winged achenes. However, the achene veins do not extend into the wings, but are close to the locule (Fig. 63, left). Wings are formed relatively late in the ontogeny of the achene. At the tip of the corolla, median veins occur in most lobes. These are short and often irregular in placement and attach ment to other veins. In the throat of the corolla (Fig. 28), a peculiar girdle of bundles is present, interconnecting the five main veins of the corolla tube. From the girdle, supernumerary veins extend downwards and upwards—mostly the latter. Some of these veins extend well up into the ligule, so that more than the minimal six veins can be found there. In other species of subg. Dendroseris, venation is essentially the same. Variations in veins at the corolla-lobe tips occur, however. Degrees in presence and absence of median veins are shown for D. macrant/rn (Fig. 29) and D. marginata (Fig. 30). In subg. Pizoenicoseris, D. pinnata (Fig. 31) demonstrates the simplified type of venation without any alteration. Veins below corolla-lobe sinuses may join at various distances from the sinus. Four veins are usually present in the achene wall. Floral venation of species of subg. Rea follows the same pattern, as shown for D. pruinata in Fig. 33. in subg. Schizoglossum, D. gigantea (Fig. 32) is notable for having a character at odds with a key character of Cichorieae: corolla lobes are separate, the ventral sinus only a little longer than the other sinuses. Corolla-lobe veins parallel the lobes, but unite just below the sinuses. If separation of lobes in D. gigantea were a vestige of an actinomorphic condition, one would expect that (1) additional veins would be present, especially in the achene, as in Dubyaea (Stebbins, 1940: Carlquist, 1961); (2) veins would extend separately in pairs beneath the sinuses instead of joining immediately below the sinuses, suggesting greater separateness of lobes, as in Glos sarion (Cariquist, 1961); and (3) vestiges of median veins in corolla lobes would be present, as in Glossarion or Dubyaea (Carlquist, 1961). None of these conditions, nor other criteria of primitive venation in Compositae, are satisfied by D. gigantea. One may assume that separateness of lobes in D. gigantea is merely an indication that lobe primordia fuse at a slightly later stage in ontogeny than in other Cichorieae. Such a change in ontogeny could easily occur in a relatively specialized genus. Similar considerations apply to the peculiarities of venation in subg. Dendroseris. Segments of median veins at lobe tips are present in an irregular fashion, as in the cultivated Fleizanthus annuus (Carlquist, 1961). Likewise, the girdle of bundles in the corolla throat of subg. Dendroseris is unrelated to any primitive pattern of

achene wall. Fifl. 56. Dendroseris berteriana. Transection of achene; vein is dark patch interior to the angle below. Fios. 51—53, X 75; Fios. 54—56, 7< 127. 114 BRITTONTA [VOL. 19

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&/$_u

FIGs. 57-62. Sections of mature achenes. FIGs. 57—58. Dendroseris pinnata. Portions of cotyledons shown below in each. FIG. 57. Transection. FIG. 58. Longitudinal section, showing folds in achene wall. FIGs. 59—62. Dendroseris marginata. FIGs. 59, 60. Transections. Fig. 59 shows a portion with ridge-like expansions of the achene wall, Fig. 60 shows a portion in which 19671 CARLQUIST: DENDROSERIS 115 venation and must be considered an innovation. Such an innovation would be expected, for the very large size of flowers in subg. Dendroseris is undoubtedly an instance of gigantism, as are the flowers of the commercial sunflower. Floral Histology. The nature of trichomes at the tips of corolla lobes proves an interesting characteristic of species in Dendroseris, reminiscent of similar dis tinctions in an unrelated genus of Compositae, Fitcl’tia (Cariquist, 1957). In D. macrophylla (Fig. 34), D. macrant/ia, and D. marginata, lobe-tips bear uniseriate non-glandular trichomes. Some of these have transverse or diagonal tip cells, some have thick lignified walls, and some have distorted shapes. In D. litoralis (Fig. 35), trichomes are fewer and less scierenchymatous; some are club-shaped. In D. gigantea, the hairiness of leaves is paralleled by the abundance of trichomes at corolla-lobe tips (Fig. 36). These trichomes have lignified walls, are two to four cells in length, and are not distorted in shape. In subg. Phoenicoseris (e.g., D. pinnata, Fig. 37) and subg. Rea (D. pruinata, Fig. 38) the uniseriate trichomes are absent. A few of the rounded cells characteristic of lobe-tips in all species bear thick lignified walls in these two subgenera, however. Trichdmes on the corolla tube show similar variations. In D. macrant/ta (Fig. 39) and D. marginata, large multiseriate non-glandular trichomes are present. These are mostly quadriseriate or triseriate at bases; they are tapered distally, terminating in one to three files of cells. Corolla-tube trichomes of D. litoralis (Fig. 40) and D. niacrophylla are similar, but smaller. In D. gigantea (Fig. 41), trichomes are abundant, but narrow, nlostly biseriate or triseriate. In all species of the subgenera Phoenicoseris and Rea, corolla-tube trichomes are sparse, short, and rounded in shape. As shown for D. pinnata (Fig. 42) and D. pruinata (Fig. 43), these trichornes are often biseriate, the files rarely more than two cells in length. In no case were glandular trichomes observed on flowers. Pollen Grains. Erdtman (1952) investigated pollen grains of Dendroseris synoptically, and provided a key to the species. This key was later reworked in terms of the segregate genera (Skottsberg, 1951). Pollen grains are figured here (Figs. 44—50) because the features reported have not hitherto been illustrated. Erdt man’s findings were confirmed by my observations. Pollen grains of subg. Dendroseris are notably large, as with D. litoralis (Figs. 44, 45), with respect to both entire grains and spines. As noted by Erdtman, sexine is connected with nexine by tenuous processes in this subgenus; spines, which are relatively long and borne on conical protuberances, are roughly equidistant from each other. No “para-apertural depressions” are present. The subgenera Schizoglossum, Phoenicoseris, and Rca agree in relatively small size of grains, and in presence of para-apertural depressions, as shown in Figs. 46 and 49. In D. pruinata (Fig. 49), however, a population of pollen grains shows various degrees of presence or absence of para-apertural depressions. An inter mediate condition is illustrated. The para-apertural depressions take the form of very thin areas of sexine (Fig. 47, left). The three subgenera seem close. They can be differentiated in terms of the protuberances and the spines these bear: conical, tipped by a spine more than 3 long in subg. Phoenicoseris (Fig. 47); rounded, tipped by short spines in subg. Schizoglossum (Fig. 48); conical, tipped by very short spines or none at all in subg. Rea (Fig. 50).

no such alterations are present. FR;s. 61—62. Longisections. Fig. 61 shows, from left to right, fibers, brachysciereids with circular pits, and thick-walled parenchyma. Fig. 62 shows, at higher power, epidermis, 1—2 layers of parenchyma, and brachysclereids with prominent circular pits. Fins. 57—61, X 135. Fin. 62, >< 245. 116 BRITTONIA 1V0L. 19

FIGS. 63—66. Sections of achenes of Dendroseris litoralis. FIG. 63. Transection of immature achenc, showing formation of the winged margin. Vein is at left. At right, two receptacular bristles. FIG. 64. Transection of mature achene. corresponding to the view shown in Fig. 63. 1967] CARLQUIST: DENDROSERIS 117

All species of Dendroseris have the same basic colpus conformation: relatively short, widened at the ends. The spines contain a central channel which is related to the lacunose structure of the outer exine. Outer sexine is composed of minute rods in a lacunose background; the inner sexine is apparently unscuiptured. Note should be made of the fact that aside from depression areas, spines are by no means exactly equidistant in any species. Germ pores are covered by a thick intine layer which is surfaced by a very thin layer of sexine. Despite the “key characters” of pollen grains within Dendroseris, the distinctions all seem to be variations on a single basic type. There is every reason to believe that the diversity has been derived from a single ancestral stock. Fruit Anatomy. Fruits in Dendroseris exhibit considerable diversity in form and anatomy. The simplest type may be seen in the subgenera Rea (Figs. 54—55) and Scizizoglossum. In D. micrantiza, the achene wall is about 6 cell-layers thick, except at the angles. Some cells in the achene wall are thin-walled parenchyma, others are prominently pitted brachysclereids. At intervals strands of fibers occur. Veins are located toward the inside of the achene wall in thin-walled parenchyma. When seen in longitudinal section (Fig. 55), the achene wall is prominently buckled; this convolution occurs prior to maturation of fibers. The above pattern characterizes species of subg. Phoenicoseris also, although these tend to have more prominent fibers in achene walls, as seen for D. berteriana (Fig. 56). This species has tannin accumulations in the epidermis. These features can also be seen, more prominently, in D. pinnata (Figs. 57, 58). The cells of the epidermis are large, densely filled with tannins. The achene wall consists wholly of fibers except for the innermost layers, which are parenchymatous and collapsed at maturity. As seen in longisection, the achene wall has conspicuous folds and bulges. The achenes of subg. Dendroseris are more elaborate in structure. In D. marginata (Figs. 59—62), achene walls are thick. The achene surface is raised into ridges (Figs. 59, 61) in some areas, although other portions lack them (Fig. 60). Achenes should probably not be termed “winged” in this species. Non-ridged portions of the wall contain two or three layers of parenchyma beneath the epidermis, followed by brachysclereids, then fibers, and finally the thin-walled parenchyrna, collapsed at maturity, lining the achene locule. Where ridges occur, parenchyma and brachy sclereids form more numerous layers and are radially elongate. Brachysclereids (Fig. 62) bear pits conspicuous for their uniformly circular outline and equal spacing. In D. litoralis (Figs. 63—66) and other species of subg. Dendroseris (excepting D. marginata), achenes are winged. Wings are dorsiventral, not lateral, in orientation. These wings are the product of meristematic action much like that which produces laminae on leaf primordia. As seen in Fig. 63, files of cells (oriented horizontally in this photograph) indicate recent divisions extending the width of the wing, just as “sheet meristem” activity widens a lamina. Before lignification of fibers obscures veins, a few vessels, sieve tubes, and laticifers may be seen in achenes. At maturity (Figs. 64—66), a pattern similar to that of D. marginata is visible. Epidermal cells are large, and do not contain tannin accumulations. Within the epidermis are about three layers of parenchyma. Within the parenchyma are one (or two) layers of

Dark cells are fibers. Fig. 65. Longisection of achene, showing ovule (left half of photograph) and achene wall, in which fibers are abundant. FIG. 66.A longisection similar to that of Fig. 65. showing histology. Tn the ovule tissue (left half of photograph), numerous large crystals can be seen. In the achene wall, the left half is composed of fibers the right half of shorter cells, the innermost of which arc brachysclereids with circular pits. Fn;. 63, X 135; Fics. 64, 65. X 110; Fic. 66. X 180. 118 BRITTONIA [VOL. 19 thin-walled brachysciereids with prominent circular pits, as shown in Fig. 66. Numer ous layers of fibers underlie the brachysciereids. Lining the locule of the achene are thin-walled parenchyma cells which are collapsed (dark line, center, in Figs. 65 and 66). Ovule cells (Figs. 65, 66, left) are not persistent; they collapse as the embryo enlarges. Prior to collapse, large prismatic crystals are evident (Fig. 66, left). The surfaces of achenes in D. litoralis are irregular, although not as markedly buckled as in D. pinnata. Achenes of Dendroseris are notable in their lack of trichomes. Trichomes are com mon on achenes of many Compositae; their absence in Dendroseris is one aspect which limits dispersibility. The function of hairs on achenes of Compositae is either to help eject them from the head (biseriate “Zwillingshaare” flex outward when mature and dry, pushing achenes up from the receptacle) or to help achenes catch on fur or feathers. Pappus bristles in many Cichorieae flex outward; this action permits ejection of achenes from the head, or provides a flotation mechanism, or both: the familiar example of Taraxacum is typical of this mechanism. Pappus bristles do not reflex in Dendroseris; they lack the differential thickenings at bases of bristles which induce this action. Gigantism is especially notable in the body of achenes in subg. Dendroseris, and to a lesser extent in the other subgenera. Pappus bristles are not proportionately increased in size or number, so there would be a net loss of dispersibility even if bristles could reflex in a normal manner (Carlquist, 1966). Embryos in Dendroseris, especially in subg. Dendroseris, are notably large, with broad cotyledons (Skottsberg, 1922). Increase in cotyledon size also results in ir regular folding of cotyledons. This was observed in D. litoralis, D. marginata, and D. pinnata. Distortions in shape of achene walls, such as buckling and convolutions, do not seem the result of increase in embryo volume. Rather, such malformations are probably a by-product of loss of dispersibility, tolerable because achenes of Dendroseris lost efficiency of dispersal prior to development of these shapes. If various factors assure that dispersal will be restricted to short distances only, mal formed achenes have no selective disadvantage (Carlquist, 1966).

TAXONOMY The species of Dendroseris as recognized by Skottsberg (1922, 1951) have been accepted here without revision. Some species characters are evident in anatomical data, particularly in leaf anatomy. More numerous characters are evident, however, at the level of subgenera. Both gross morphology and anatomy of Dendroseris are presented in Table I. The distinctions assembled in Table I, however, do not in clude any expressions constant throughout Dendroseris as a whole. Most of the character expressions in Table I distinguish one of the subgenera from the other three. In the majority of cases, such separations divide subg. Dendroseris from the other three subgenera. In some features, these distinctions underline the gigantism so typical of subg. Dendroseris—heads, flowers, achenes, and pollen grains, for example. The basis for this gigantism would be interesting to know. It evidently does not lie in polyploidy. Cytological investigations by Stebbins, Jenkins, & Walters (1953) showed that the somatic chromosome number 2n = 36 occurs not only in a species of subg. Dendroseris (D. macrophylla) but also in a species of subg. Phoenicoseris (D. pinnata). The same number has also been counted in D. litoralis of subg. Dendroseris (Raven, unpubl.), and in D. pruinata of subg. Rea (Soibrig et al. 3849, Más a Tierra, Puerto Ingles, GH, US. I am grateful to Dr. Soibrig for per mission to publish his count here). This number suggests that Dendroseris as a whole may be a polyploid derivative from the basic number x 9 which is present in sub- tribes related to Dendroseridinae. 1967] CARLQUIST: DEND0SERIS 119

TABLE I CSIARACTERISTICs DIFFERENTIATING SUBGENERA ix D endroseris.

Dendroseris Schizoglossum Phoenkoseris Rea

Habit Branched Rosette shrub Palmiform Rosette shrub rosette tree

Pith Hollow Solid Hollow Solid (diaphragms) (diaphragms)

Leaves Entire, ± ovate Entire, elongate Pinnate, elongate Entire, elongate Thin to thick, gla- Thin, hairy Thick, glabrous Very thick, brous glabrous

Inflorescence Heads few, large Heads many, small Heads many, small Heads many, small

Head Receptacle bristly No bristles Receptacle bristly No bristles

Achenes Winged, large, Non-winged, small, Non-winged, small, Non-winged, small, thick-walled thin-walled thin-walled thin-walled

Corollas Large, orange Small, white Small, white Small, white Ligules entire Ligules 5-fid Ligules entire Ligules entire Supernumerary Venation simplified Venation simplified Venation simplified veins in corolla Trichomes at lobe Trichomes at lobe No trichomes at No trichomes at tips tips lobe tips lobe tips Tube hairs large Tube hairs medium Tube hairs few, Tube hairs few, short short

Pollen Grains large Grains small Grains small Grains small No depressions Depressions Depressions Depressions ± Protuberances coni- Protuberances round, Protuberances coni- Protuberances coni cal, spines long spines short cal, spines short cal, spines very short Sexine to nexine No processes No processes No processes processes

One might, on the basis of the data in Table I, more easily recognize two segregate genera than four, if segregate genera were desirable. Subgenera, however, seem quite adequate for the purpose of expressing the variation pattern of the Juan Fernandez Cichorieae. Although two subgenera might be an acceptable taxonomic solution, the four subgenera seem advisable because each of the species groups thus em phasized possesses several clearly defined and significant characters. Recognition of a single genus, Dendroseris, seems the most satisfying treatment because divergences such as those listed in Table I can be explained as variations on a single basic pattern. Moreover, the characters common to all the species are not expressed in Table I. Characteristics in which expressions appear to be variations on a single plan include trichome types on corollas, venation of flowers, nature of achene-wall anatomy, vascularization pattern of stem and leaf, and involucral bract anatomy. Presence of hypodermis, bundle-sheath extensions, and palisade cells isodiametric in shape are features common to leaves of all species. Pollen grains are basically alike, most notably in the shape of furrows and the fiber structure of exine. This basic group of unifying characters suggests that a single ancestral stock can be envisioned for all the species of Dendroseris. Seen thus, the characteristics of subgenera and species are evidences of adaptive radiation not unlike that which characterizes other insular genera, such as Dubautia (Compositae) and Cvanea (Campanulaceae) in the Hawaiian Islands, or Aconium (Crassulaceae) and Sonchus sect. Dendrosonchus (Compositae) in the Canary Islands.

65—91. 112: Woods Trop. (Compositae). Cichorieae of Wood anatomy 1960. •

78—93. 10: positae). Brittonia

(Corn and Yunquea of Centaurodendron position and systematic Anatomy 1958. •

29: 1—144. Bot. Pubi. California Univ. (Compositae). genus Fitchia The S. 1957. Cariquist,

CITED LiTERATURE

as such Dendroseris. trees rosette herb-like of nature

the concerning information anatomical and floristic, taxonomic, comparative fund of

by increasing an supported not is it conditions, relict under awkward hypothesis these

only the is Not evidence. geological of to oceanic according have developed, islands

floras which in times short relatively the to must during be vanished imagined have

moreover, relatives, continental such areas; vanished on continental trees rosette

now- hypothesize must one relictual. are islands rosette herb-like oceanic trees on

peculiar of species and genera the many that if assumes (Cariquist, one 1962).

elsewhere discussed reasons for dicotyledons, of groups woody major the for ancestry

of hypothesis the with conflict not idea is in This conditions. xylem certain under

secondary of accumulation increase can species herbaceous and involved, bility is

flexi considerable dicotyledons, of groups in individual that however, stress, must

One deserves. it acceptance gained the has herbs than are more primitive species

woody large, at dicotyledons in that The idea 1965). by (Cariquist, the writer trees

rosette Fernandez Juan the for earlier suggested been has hypothesis This island.

oceanic an of assemblage floristic disharmonic the in but on continents present

not opportunities to as ecological well as conditions, uniform and relatively mild

climatically herbs to of responses the as explained best seem stems of .Dendroseris

succulent and accumulation xylem The limited xylem. secondary to form extensive

ability the lost have which a group probably are Cichorieae ancestors. woody from

derived directly considered be to juvenilistic highly too is it of herb; an that tially

essen is wood that Dendroseris indicate 1960) (Carlquist, Cichorieae of anatomy

on Studies regard. in this pertinent very is wood anatomy from evidence The

1958). quist,

(Carl example for sect. Plectocephalus, Centauraea from derived appear quea Fun

and Centaurodendron relatives. mainland of offshoots be specialized to shown

can be These (Cynareae). and Yunquea Centaurodendron (Senecioneae); chaeta

and Symphyo Rhetinodendron, Robinsonia, Compositae: are shrubs rosette and

of trees rosette most the hand, other the On there. forms growth such demonstrate

Islands Juan Fernandez the on families primitive relatively the of None families.

primitive in them more expect would one forms, ancient were islands oceanic on

shrubs and rosette trees If rosette condition. insular the to related specialization

a but as antique, regarded be cannot form growth The tenable. seem not does

1956) (Skottsberg, a relict is Dendroseris that conclusion The Cichorieae. within

advanced or primitive notably are Stephanomeriinae nor Dendroseridinae Neither

1953). Walters,

& Jenkins, (Stebbins, once referred was it which to phanoineria, that Ste of as same

the is number chromosome its Stephanomeriinae; in be placed also must fornia),

(Cali island Clemente San to endemic Munzothamnus, Stephanomeriinae. in Chile,

Islands, the Desventurados to endemic shrubs succulent of genus a Thamnoseris,

places (1953) Stebbins be envisioned. can Stephanomeriinae and droseridinae

Den between relationship A isolation. geographical and form growth to related

peculiarities measure small no stresses in treatment This authors. various by followed

been has Dendroseridiriae, subtribe, a separate in genus this of placement The here.

been explored not have other Cichorieae and Dendroseris between relationships The

CONCLUSIONS PHYLOGENETIC

19 VOL BRITTONIA 120 1967] CARLQUIST: DENDROSERIS 121

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