RHIPSALIS MICRANTHA COMPLEX
By Wilhelm Barthlott
From TROPISCHE UND SUBTROPISCHE PFLANZENVELT 10 (1974)
Translated to the English by Luc Scherens
Notes about the systematics of the genus Rhipsalis and the setting up of the Rhipsalis micrantha complex.

Rhipsalis micrantha (HBK) DC was discovered and described at the beginning of the last century. RAUH has brought back living material from several journeys to Peru (1956, 1970 and 1971) and Ecuador (1954), , which correspond with the original diagnosis, the picture by Britton & Rose (1923, p. 239) and also under this name are cultivated plants (see pic. 102 in RAUH 1958).
Our collections in 1973 from Ecuador and North Peru, besides the typical 2- and 3-sided R. micrantha, brought a whole group of close related taxa, whose territory spreads from the coastal areas of West Ecuador, the dry forests of North Peru up to altitudes of 2000 m in several elevated valleys of the inner Andes and in the east to the source rivers of the Amazon.
Amongst the new found specimens there were long pending epiphytes with sharp 5-sided branches (R. kirbergii, see pic 5-6) and plants with leaflike flattened stems with almost Zygocactus truncatus-like appearance (R. rauhiorum see pic 10-11).
In spite of their completely different habits, they are related through transitional forms and differ insignificantly by their flower-, pollen- and seed morphology. They form a well determinate group inside the subgenus Goniorhipsalis K. SCH. and will be called the Rhipsalis micrantha complex in this work.
According to the present literature and our proper research, they are actually the only representatives of the subgenus Goniorhipsalis in Ecuador and Peru.

The Rhipsalis micrantha complex gives some interesting directions to the general systematics of the genus Rhipsalis GAERTNER. The current classification in subgenera is based exclusively on the morphological characteristics of branches and emanates from F. BUXBAUM(1970). According to him the here treated species should be split up in 2 different subgenera, namely Rh. micrantha and R. kirbergii in subgenus Goniorhipsalis K. SCH., Rh. rauhiorum in subgenus Phyllarthrorhipsalis BUXBAUM.

Such an assignment, only based on branch-morphological criteria is phytographically very valuable and in many cases also phylogenetically (racially) correct. But, in part, this also creates absolute artificial groups. Species with leaflike, flattened stems can originate in the reduction of the number of ribs during quite simple steps in evolution, as the present example shows. (NOT IN PAPER!). The flower-, pollen- and seed morphology of a larger number of examined specimens of the subgenus Phyllorhipsalis sensu SCHUMANN, show that it concerns a polyphyletic (developed from more than one ancestral type) artificial group.

This is even more the case for the subgenus Rhipsalis sensu BUXBAUM 1970, which is clarified by this example : Rh. baccifera (MILLER) STEARN, Rh. leucorhapis K. SCH. and Rh. megalantha LOEFGREN which have the spiralling areoles in common, a typical characteristic for the subgenus. Though, flower-, pollen- and seed morphologically seen, these species have hardly anything in common. R. baccifera, with its small flowers, is hardly distinguished from many species of the subgenus Goniorhipsalis (e.g. from R. micrantha) on flower- and seed morphology base. Rh. megalantha, with its big, sunken flowers, together with some other species, builds a well-defined proper group. Finally, R. leucorhapis deviates completely, because of its bell-shaped flowers, that for example lack a disc.

At present, we can not present a better system than the already existing ones, but with confidence it can be said that these systems are partially artificial and therefore not phylogenetic(racial). Only further, conscientious studies can provide a clarification.

1. Rhipsalis micrantha (HBK) DC emend. BARTHLOTT

Literature :
Cactus micranthus HUMBOLDT A. v., BONPLAND, A. & C.S. KUNTH, in : Nova Genera et Species Plantarum VI, p. 65, Paris 1823.
Rhipsalis micrantha (HBK) A. P. DE CANDOLLE, in : Prodomus Systematis Regni Vegetabilis III, p. 476, Paris 1828
Hariota micrantha (HBK) C. KUNTZE, in : Revisio Generum Plantarum I, p. 203, 1891
As Rh. micrantha (HBK) DC, in : WEBER 1898, p. 1046; SCHUMANN 1903, p. 140 (non sensu SCHUMANN 1898, p. 631); BRITTON & ROSE 1923, p. 320; VAUPEL 1926, p. 81; RAUH 1958, p. 228; BACKEBERG 1959, p. 607.

Original diagnosis (according to HUMBOLDT, BONPLAND & KUNTH, l.c.) :
C. pendulus; inermis; ramis 3-4-angularibus; vel compresso-ancipitibus; floribus minutis; albis; Crescit in arboribus (in Mimosa farnesiana; Lonicera, etc.), prope Olleros Quitensium, alt. 740. hex., locis temperatis."
The diagnosis is completed with the next sentence, which does not add any essential data:
"Parasiticus; pendens; ramosus; inermis; glaber. Caulis ramique 3-4-angularis, aut saepius compresso-ancipites. Flores ex angulis erumpentes, solitarii, sessiles, albi, minuti. Bonpl. mss. »

On the basis of the gatherings of RAUH & BARTHLOTT No. 35142 (km 34, road from Saraguro to Loja, South Ecuador, alt. 1900m) and RAUH No. 35483 (between Chiclayo and Huancabamba, North Peru, alt. 650 m) the inadequate diagnosis can henceforth be enlarged and emended :

Plants epiphytic, from spreading half-erect to mostly 1,5 m long hanging growth, abundant acrotonically branched; lateral branches sometimes building whorls (pic. 2-4).
Shoots 2- to 3-sided ; primary shoots often 4-sided (quadrangular). Shoot segments succulent, not leaf-like thin, linear, at the edges smooth till weakly crenated and with yearly determined growth, 0,7 to 1,3 cm wide and 7 to 18 cm long.
Areoles very small, without bristles and with barely visible tomentum; new growth with an insignificant delicate (fragile) deciduous leaf and often with ca. 1 mm long extranuptial nectary.
Branch epidermis dirty green with elongated, ca. 70µ wide and 100-150µ long cells with smooth surface; stomata not sunken (pic. 19).
Flowers single, lateral on the branches (pic. 3), whitish-transparent, radial, 6-10 mm diameter, sometimes only half opening.
Petals 5 to 7, the innermost up to 4,8 mm long and 4 mm wide, egg-shaped (oval) to elongated oval (pic. 15, 1a-b).
Style erect, 4-5 mm long, with 3 to 4 sidewards spreading papillose lobes. A well formed disc at the base of the flower.
Stamens 25 to 35, 2-3 mm long, anthers small, whitish,.
Pollen 6- to 8-colpat(??), round, ca. 50µ diameter (pic. 21) Colpi ca. 20 µ long. Exine very regular with superficial punctures and 0,3µ long spinules (pic. 24).
Pericarp lightgreen, not sunken in the stems, naked, only very exceptional with separate
scales.
Fruit a spherical naked berry; ca. 8 mm long and 6 mm broad, white, sometimes reddish towards the top.
Seeds ca. 30-40 per berry, brown-black, elongated oval, ca. 1,4 mm long and 0,6 mm broad with an oval hilum (pic. 17c). Testa completely smooth (pic. 18) with ca. 80-140µ long and 45 µ wide cells without secondary structure.
Chromosomes 2n=22 (extracted from root ends).
Variable and ecologically well adapting species, which appears as epiphyte (very seldom as epilithic) in different plant formations and altitudes :
In the evergreen rainforests at sea level near Machala (Southwest Ecuador (RAUH & BARTHLOTT No. 35079)) and between Esmeraldas and Santo Domingo (West Ecuador (RAUH & BARTHLOTT No. 34331)); in raingreen Ceiba-forests of South Ecuador and North Peru, e.g. near Macara (RAUH & BARTHLOTT No. 35306); in North Peru near Taulis (HOFFMANN No. 896) and between Chiclayo and Huancabamba (RAUH No 35483),.
Appears to be lacking at the western slopes of the Andes in northern and central Ecuador, grows however in southern Ecuador up to altitudes of 1900 m, e.g. at km 34 of the road from Saraguro to Loja (RAUH & BARTHLOTT No 35142). Wide spread, but still quite seldom on the eastern slopes of the Andes between 500 and 1000 m altitude near Puyo, Macas and Zamora in Ecuador; in eastern Peru at 1200 m altitude between Chamaya and the Marañon (RAUH 24334).
HUMBOLDT & BONPLAND collected this species first in 1802 near Olleros in North Peru (in those days part of Ecuador) at ca. 1500 m altitude and described it in 1823. A. WEBER has examined HUMBOLDT's original material at the Paris herbarium and found that this 2- to 3-sided specimen was not identical to the Rh. micrantha species that was cultivated in Europe around the turn of the century. He described this five-sided, large-flowering family as Rh. sulcata. After him, K. SCHUMANN (1898, p. 631) has mistakenly put together his description of Rh. micrantha, but revised this error in the supplement in 1903 (p. 140). See therefore the elaborated description of the Rh. sulcata problem in the next chapter.

2. Rhipsalis kirbergii BARTHLOTT, spec. nov.

Footnote to title : The species is named after Dr. HANS KIRBERG, a meritorious Rhipsalis collector, who has put up an extensive collection of epiphytic cacti in Altlünen/Westfalen

Synonym Rh. sulcata sensu GRAF 1963, non sensu WEBER 1898: ….
Literature GRAF A B: EXOTICA 3, p580 and 1704 ( as Rh. sulcata). Rutherford N J. USA 1963

Plant epiphytic, bushy, up to 2 m long and pending, acrotonically branched and regularly building whorls. (pic. 5-6)
Shoots 5-sided, sometimes 4-sided, exceptional up to 6-sided; sharp ribbed. Branches 4-7 mm thick, 18-30 cm long, with yearly determinate growth.
Branch epidermis pale green; cells ca. 50µ wide and 200µ long, with smooth surface; stomata not sunken.
Areoles very small, without bristles and with barely visible tomentum, not sunken; new growth with insignificant delicate deciduous leaf .
Flowers single, lateral on the branches (pic. 7), whitish-transparent, radial, 6-8 mm diameter and 6-8 mm long, sometimes only half opening.
Petals 5 to 7, the innermost up to 4,5 mm long up to 2,5 mm wide.
Style erect, ca 4 mm long, with mostly 4 spreading papillose lobes. A well formed, whitish disc at the base of the flower. Stamens 25 to 35, 2-3 mm long, anthers small, whitish.
Pollen 6- to 7-colpat, round, ca. 50µ diameter (pic. 20); Colpi ca. 20 µ long. Exine somewhat lesser closed as with Rh. micrantha (HBK)DC with ca. 0,3µ long spinules; near the very regular superficial punctures with small, irregular tectal perforations.
Pericarp lightgreen, not sunken in the stems, naked, only very exceptional with separate
scales.
Fruit a spherical naked berry; ca. 6 mm long and 5 mm broad, dirty white, often with a red overlay.
Seeds ca. 30 per berry, blackbrown, elongated oval, ca. 1,4 mm long and 0,6 mm broad with an oval basal hilum (pic. 17a). Testa completely smooth with ca. 90µ long and 40 µ wide cells without secondary structure.
Chromosomes 2n=22 (extracted from root ends).
Habitat : epiphytic on old trees, ca. 10 km north of Chone, Province of Manabi, West Ecuador, at ca. 200 m altitude.
Holotype : RAUH & BARTHLOTT No. 34364 in the herbarium of the Institutes für Systematische Botanik der Universität Heidelberg. Clonotypes are to be found in culture in the Botanical Garden of the University of Heidelberg, the succulent collection of the city of Zürich and some other collections.
The new species is characterised by its long pendent, sharp ribbed, regularly acrotonic branched shoots and its very small flowers. The specimen, that was collected in Ecuador in August, has flowered unusually rich in December in Heidelberg. In its habitat it grows sporadically on old Calebas trees (Crescentia cujete), in company of Tillandsia disticha (green, myrmecophile (ant loving) form), Tillandsia complanata (yellow low land form), and the orchid Rodriguezia spec.
Initially we considered this species to be Rh. sulcata WEBER; one also comes to this conclusion when following the determination keys of BRITTON & ROSE (1923) and BACKEBERG (1959). Our plant is also illustrated as Rh. sulcata in the "Exotica" of GRAF (1963), indicated as originating from Ecuador.
WEBER (l.c.) described Rh. sulcata based on garden plants of unknown origin, that were cultivated as "Rhipsalis micrantha" in France and Germany around the turn of the century. The probably only authentic illustration of the species is given by BRITTON & ROSE (1923, p. 235), based on material they received from Paris in 1902 (probably a clonotype). Rh. sulcata WEBER appears to be no longer in culture in Europe; what was illustrated by GRAF (1963) and frequently imported from Ecuador during the last years, is another species, that has been described above as Rh. kirbergii spec. nov.
According to the original diagnosis by WEBER and the indications by BRITTON & ROSE, the following differences are found :

Rh. sulcata WEBER 1898
Branch stump five-sided, 10-15 mm thick; flowers quite big, ca. 18 mm diameter, whitish to pink.

Rh. kirbergii spec. nov.
Branch sharp 5-sided, 4-7 mm thick; Flowers very small, ca. 6-8 mm diameter, whitish to greenish white.

In southern Ecuador we have collected a very deviating form from appearance and habitat of Rh. kirbergii, which should be described as a proper variety :

Rhipsalis kirbergii BARTHLOTT var. monticola, var. nov.

This variety is distinguished from the type species var. kirbergii by its thicker, 8-11 mm broad branches (pic. 8 and 14), its dirty olive green epidermis and its spreading overhanging growth; its insignificant flowers don't show any difference with the type. Grows epilithic on rocks and epiphytic in dense bush ca. 5 km south of Loja (South Ecuador) at a for Rhipsalis unusual altitude of 2000 m, in company of big epilithical tillandsias from the T. fendleri-group and T. straminea.

3. Rhipsalis rauhiorum BARTHLOTT, spec. nov.

Note to the title : This species is named after WERNER and HILDE RAUH, who discovered it during a joint excursion in the valley of the Rio Catamayo (South Ecuador) in September 1973

Plant epilithic, hanging over, bushy, up to 1 m long, branching richly acrotonically (occasionally also mesotonically); sometimes building whorls.
Shoots 2-sided (primary branches 3- to 4-sided), leaf-like flattened, succulent. Shoots strongly crenate, 1,9-2,2 cm wide and 5 – 10 cm long with yearly determinate growth (pic 10-12).
Areoles very small, without bristles and with barely visible tomentum; only new growth with insignificant delicate deciduous leaf .
Branch epidermis dull green with ca. 70 x 100 µ big cells and smooth surface; stomata not sunken.
Flowers lateral on younger shoots, single or sometimes with two, whitish (because of the sometimes intensive colored disc often with a red centre), radial, 7-11 mm in diameter and 8-9 mm long.
Petals 5 to 9, whitish transparent, elongated acuminate, the innermost up to 5 mm long and 2,5 mm wide.
Style erect, 4 mm long, with mostly 4 back curved lobes. At the base of the flower a well formed, whitish to mostly carmine disc. Stamens 25 to 35, 2-3,5 mm long, anthers small, whitish.
Pollen 6- to 8-colpat, round, ca. 50µ diameter (pic. 22); Colpi ca. 20 µ long. Exine (pic. 25) closer as with Rh. micrantha (HBK)DC with ca. 0,3µ long spinules, near (or next to) the regular superficial punctures with irregular tectal perforations.
Pericarp lightgreen, naked, only seldom with vestigial areoles, not sunken in the stem.
Fruit a spherical, naked, ca. 7 mm long and 5,5 mm thick, dirty white berry, often with a red overlay.
Seeds ca. 25-35 per berry, blackbrown, elongated oval, ca. 1,4 mm long and 0,6 mm broad with a basal oval hilum. Testa completely smooth with ca. 90 – 150 µ long and 40 µ wide cells without secondary structure (pic. 17b).
Chromosomes 2n=22 (extracted from root ends).
Habitat : epiphytic on old trees in raingreen Ceiba pentandra forest of the Rio Catamayo valley (South Ecuador) at 1300 m altitude;
Holotype : RAUH & BARTHLOTT No. 35278 in the herbarium of the Institutes für Systematische Botanik der Universität Heidelberg. Clonotypes are to be founded in culture in the Botanical Garden of the University of Heidelberg, the succulent collection of the city of Zurich and in some other collections.

Rhipsalis rauhiorum is a very remarkable species, which in its habitat reminds of Zygocactus truncatus. The specimens that have been collected in Ecuador in September, have flowered abundantly in culture in December. In its habitat the species is accompanied by xeromorph Bromeliaceae like Vriesea espinosa, V. barclayana, Pitcairnia spec. (aff. P. pungens), Tillandsia capillaris, T. disticha, T. latifolia var divaricata, and others. Rh. rauhiorum appears to be a very variable species. From East Ecuador we obtained a remarkable, very elegant form with rose-coloured berries (RAUH & BARTHLOTT 34737); it was found at an altitude of 1000 m near Puyo (Oriente) by JOEL BRENNER. A very divergent form with longer, leaf-like flattened stems grows in North Peru on the west slopes of the Andes, between 1200 and 1700 m altitude, near the road to Ayabaca, epiphytic on old trees (pic. 9) and on Gymnocereus (Browningia) microspermus (RAUH & BARTHLOTT No. 35307 and 35308).
Rhipsalis roseana BERGER from Columbia and Costa Rica is to be considered as a closely related species,. According to its original diagnosis and the cultivated Columbian plants (BG HEID No 35981 from the MARNIER-LAPOSTOLLE collection) this species distinguishes itself by its smaller and thinner stems and the form of the flowers as well as by the colour of the ripe fruit. Rh. rauhiorum is – compared to Rh. roseana – a xenomorph habitant of the (for the genus Rhipsalis) extreme dry biotopes. On the other side it appears to go from Rh. rauhiorum via the larger, flattened intermediate forms to Rhipsalis goebeliana (HORT.?) BACKBG., which up to now was only known in culture. Here we can find probably the origin of the subgenus Phyllorhipsalis.

Relationships within the Rh. micrantha complex.

The three habitually well distinct species are characterised by only very small differences in their flower, pollen and seed morphology. Furthermore they are linked to each other by intermediate forms, forming a well defined group.

Rh. micrantha is the most wide-spread of them all, covering the total area (see the distribution map fig. 26) from North Ecuador till North Peru (somewhat up to the geographical latitude of Trujillo); probably its area reaches in the north up to southern Columbia. Rh. kirbergii we have found twice in West and South Ecuador; Rh. rauhiorum appears to be limited in its distribution to southern Ecuador and northern Peru.
The five-sided Rh. kirbergii might be the most primitive member inside the complex (compare pic. 13 and 14); due to a reduction of the number of ribs and via 3- to 2-sided Rh. micrantha, the 2-sided Rh. rauhiorum could be morphologically derived . This morphological series (pic. 13) is also phylogenetically "correct" (with the above reasoning), and is confirmed by the subtle differences in the pollen morphology (pic. 20-25). The structure of the exine is manifestly stronger from Rh. kirbergii via Rh. micrantha to Rh. rauhiorum. Inside the relationship circle and according to the pollen morphology experience, this may be interpreted as evolution. The supposed relationships are shown in pic. 16.

Gall formation on Rh. micrantha and Rh. rauhiorum.
In the dry valleys of northern Peru we have gathered Rhipsalis specimens, whose taxonomical classification at the beginning brought big difficulties. Habitually the specimen looked like a form of Rh. rauhiorum with long, leaf-like branches (on the road to Ayabaca, west slopes of the Andes at 1700 m altitude, growing epiphytically on Gymnocereus microspermus; RAUH & BARTHLOTT 35307) or like a strong form of Rh. micrantha (in Bromeliaceae rich dry forest southeast of Chiclayo near Tocmoche at ca. 1200 m altitude; RAUH & BARTHLOTT 35325). These forms caught the eye because of a conspicuous and taxonomical important detail :
The major part of the areole is strongly enlarged, with dense tomentum and deeply sunken in the stem (pic. 27 and 28). Based on these characteristics, we considered these specimen to be a new Lepismium (sensu BACKEBERG), yet this genus, related to Rhipsalis, is only known from Brasil, Paraguay and Argentina. The problem got even more confused when we found populations in the valley of Ayabaca at 1200 m altitude (RAUH & BARTHLOTT 35308), that didn't show these lepismoid areoles (pic 27 left).
A close examination of the living and alcohol conserved material quickly gave an explanation to the phenomenon : a parasite had laid eggs in the growing points of the areoles. Subsequently transformation of the areole followed : the centre of growth develops into a spherical gall, (Acrocecidium), and in which a yellow, maggot-like parasite larva is growing. The areole enlarges considerably and a strong growth of hairs ensues. (see Fig. 29). As far as the morphogenesis on the deformed areole can be reconstructed, two different factors are responsible for the sinking in the stem : firstly the areole is surrounded by bark tissue, and secondly the vesicle cords of the infected areole are no longer extended at primary thickness growth of the stems and therefore the areoles become sunken. Conglomerations of up to 5 galls have been observed per areole.
From the phylogenetical-evolutionary point of view, the morphology of the areoles of Rhipsalis is very interesting. The chemically induced stimulus, given by the developing parasite (a traumatomorphosis can be excluded in this case) leads to a formation of a (for Rhipsalis) completely abnormal areole, which resembles those of Lepismium (sensu BACKEBERG) even in detail (compare pic. 27). The morphogenetical power to build "lepismoid" areoles is also found in Rhipsalis but never breaks through in normal ontogenesis (development), it stays latent.
According to the examinations of BOYSEN-JENSEN (1952) on Mikiola fagi (HTG) these cecidogene substances are growth regulators, which essentially are equal to those that are working in normal plant tissue. This reported areole morphosis is an impressive example for the theory about gall formation by WERTH (1948; cited in BUHR 1964). Form anomaly can also lead to perception of the phylogenetic coherence in this range.

Summary

The representatives of the subgenus Goniorhipsalis K. SCH. (Rhipsalis; Cactacaeae) from Ecuador and Peru are represented; their seed and pollen morphology has been examined with a raster electron microscope and illustrated. It concerns 3 close related species with equal chromosome number (2n=22) :
Rhipsalis micrantha (HBK) DC, whose description has been emended. The 2- to 3-sided species is spread more widely than expected ; its area reaches from northernmost Ecuador to the western and eastern slopes of the Andes in Peru (somewhat geographical latitude of Trujillo).
Rhipsalis kirbergii BARTHLOTT with sharp 5-sided branches from West Ecuador and its var. monticola BARTHLOTT have been newly described.
Rhipsalis rauhiorum BARTHLOTT with leaf-like flattened branches and a Zygocactus truncatus-like habitat from South Ecuador and North Peru has been newly described.

A gall formation on Rhipsalis in North Peru, caused by a parasitic insect and which provokes a remarkable morphosis of the areoles, is mentioned : the abnormal areoles are sunken, enlarged and woolly; therefore they resemble strongly the close related genus Lepismium PFEIFFER. This remarkable conclusion has been discussed with phylogenetic-evolutionary points of view.

Fig. 1 : Rh. micrantha (HBK) DC in company of epiphytic Bromeliaceae at 1900 m altitude in South Ecuador
Fig. 2 : Rh. micrantha. Detail of one of the plants from fig. 1
Fig. 3 : Rh. micrantha, 3-sided form in flower
Fig. 4 : Rh. micrantha, 2-sided form from the coastal lowland near Machala/Ecuador
Fig. 5 : Rh. kirbergii, holotype from the coastal lowland near Chone/Ecuador
Fig. 6. Rh. kirbergii, with its characteristically sharp five-sided, pseudowhorled branches
Fig. 7 : Flowers and young fruit on Rh. kirbergii (holotype)
Fig. 8 : Rh. kirbergii var monticola, holotype of the variety, South Ecuador, near Loja at 2000 m altitude
Fig. 9 : Small branched form of Rh. rauhiorum in North Peru at 1100 m altitude growing in company of Tillandsia juncea
Fig. 10 : Rh. rauhiorum. Shot at the habitat of the holotype in the valley of the Rio Catamayo, South Ecuador, at 1300 m altitude.
Fig. 11 : Rh. rauhiorum, acrotonically branched, leaf-like, serrated stems of the holotype
Fig. 12 : Rh. rauhiorum, flower and fruit of the holotype
Fig. 13 : Morphological line of the reduction of the number of ribs of the Rh. micrantha complex : (A) Rh. kirbergii; (B) Rh. kirbergii, foursided branch; (C) Rh. micrantha, three-sided form; (D) Rh. micrantha, two-sided form; (E,F) intermediate forms to Rh. rauhiorum; (G) Rh. rauhiorum
Fig. 14 : from left to right : etc….
Fig. 15 : 1a, 1b Flower of Rh. micrantha, 2a, 2b flower of Rh. rauhiorum
Fig. 16 : diagram of the supposed relationship inside the Rh. micrantha complex
Fig. 17 : Seeds of Rh. kirbergii (A); Rh. rauhiorum (B) and Rh. micrantha (C); magnification 50x. The visible differences are still within variability of the single species
Fig. 18 : Testa of the seed of Rh. rauhiorum. Magn. by 200
Fig. 19 : Epidermis of Rh. micrantha. Magn. by 50. One recognises the elongated epidermis cells and the not sunken stomata.
Fig. 20-25 : to pollen morphology of the Rh. micrantha complex : fig. 20-21 (upper row) Rh. kirbergii (holotype); Fig. 22-23 (middle row) Rh. micrantha; Fig. 24-25 (lower row) Rh. rauhiorum (holotype). Magnification : left column 900x, right column 2000x
Fig. 26 : Distribution map of the Rh. micrantha complex in Ecuador and Peru according to actual gatherings
Fig. 27 : left : normal branch of Rh. aff. micrantha; middle : branch of the same plant with lepismoid areoles caused by gall forming; right : normal branch of Lepismium (sensu BACKEBERG) marnierianum BACKBG.
Fig. 28 : Section of the branch of Rh. spec with abnormal lepismoid areoles caused by the infection by a parasitical diptera; under the epidermis there are tunnels of another parasitical insect.
Fig. 29 : Areole morphosis due to gall formation, schematic. Left : areole in view from above (hair removed), 4 cecidien are recognised. Right : the same areole in longitudinal cross section. A : circumvallate bark tissue; B : gall tissue; C : areole hairs; D : young parasite larva; E : hatched empty gall; F : parasite nymph.