BLUMEA 22 (1975) 275 —294

Note on the pollen morphology

of s.l.

Jan Muller

Rijksherbarium, Leiden, Netherlands

Summary

The of the and pollen morphology genera , , Axinandra,

is in view ofa unitethese in Three compared proposal to genera Crypteroniaceae. pollentypes are recognized,

differingin aperture and shape symmetry, but showing distinct similarities in exine and aperture structure. It is that the found in and and the argued heterocolpatetype Dactylocladus, Axinandra, Rhynchocalyx bisyn-

colporate type characterizing Crypteronia, may both have been derived from a less-specialized tricolpate in ancestral type which has been retained Alzatea. The wider affinities of Crypteroniaceae are discussed and

and Cunoniaceae thought to be with Lythraceae Melastomataceae, although a more remote relationship with

s also possible.

Introduction

Therevision of the Crypteroniaceae, precursory to "Flora Malesiana", by VanBeusekom-

Osinga & Van Beusekom (1975) has resulted in a new delimitation of the family by

Van Beusekom (1975), now including Crypteronia, Dactylocladus, Axinandra, Alzatea, and The Rhynchocalyx. pollen morphology of these genera was studied in order to supplement

anatomical & the macromorphological and (Van Vliet, 1975; Van Vliet Baas, 1975) data.

This note is restricted to a presentation of the pollen morphological results only, and for a discussion ofthe full taxonomical problems involved reference is made to the papers cited.

The of the pollen Crypteronia has been studied previously by Erdtman (1946, small that 1952), who was much handicapped by its size; of Alzatea was described by

Lourteig (1965). The pollen of the remaining genera has not been described before.

Dactylocladus, Rhynchocalyx, and Alzatea are monotypic genera, Crypteronia contains

four which were all available for pollen morphological examination.Of Axinandra,

however, only one of its three species could be studied. Unless indicated otherwise, all

material originates from the Rijksherbarium (L).

Ripe anthers, taken from closed buds, produced best results. Acetolysis was applied for

two minutes according to standard procedure, and the pollen grains were mounted in

glycerine-jelly for light microscopical (LM) examination. For scanning electron micro-

scopy(SEM) the acetolysed grains were coated under vacuum with carbon, followed by

gold. Sections were cut with a freezing microtome according to a technique, described

in detail elsewhere (Muller, 1973). For transmission electron microscopy (TEM) the

acetolysed grains were fixed in 2% OsC>4 (cacodylate buffer), pre-stained in 5% uranylace-

tate and embedded in Eppon 3/7.

The author thanks Dr. & Mrs. C. F. van Beusekom-Osinga and Mr. P. Baas for

stimulating discussions. He is also indebted to Dr. E. M. van Zinderen Bakker (Bloem-

for of to Hideux for fontijn) supplying a pollen sample Rhynchocalyx, Dr. M. (Paris) 276 BLUMEA VOL. 22, No. 2, 1975

of Mr. W. H. Star permission to quoteunpublished information onpollen Cunoniaceae, to the of for preparation sections, and to Mr. H. Kammeraat (Geological Institute, Leiden)

for assistance in SEM work.

GENERAL MORPHOLOGY

be the Alzatea- Three pollen types can recognized in Crypteroniaceae: tricolporate type, the and heterocolpate Dactylocladus- type (Dactylocladus, Axinandra, Rhynchocalyx) in

which three colporate apertures alternatewith three pseudocolpi, and the bisyncolporate

Crypteronia-type. While the orientation of the apertures in the first two types is clearly

that in the self-evident. Erdtman assumed meridional, Crypteronia-type was not (1952) a

meridionally oriented, encircling colpate aperture to be present, with two minute endo- situated the short The observations apcrtures at ends of the grain on the equator. reported which assisted the resolution of the here, were greatly by higher stereoscan images, confirm essentially this interpretation. Moreover, in some samples heteropolar grains which the distal be occur in pole would situated on the more convex side, according to observations made other during tetrad development in bicolporate pollen types by

Huynh (1968). However, the two equatorially oriented grooves, mentioned by Erdtman,

have proven to be pseudocolpoid depressions, and these are not invariably present.

in and The colporate apertures are all pollen types more or less strongly invaginated which rather closed by a membrane is distinctly outlined against the border of the thicker At these mesocolpia. the equator apertures may be bridged and the underlying endo- be less apertures, representing interior, thinned endexine areas, may more or distinctly

developed. The pseudocolpi are rather similar in general construction but are not bridged,

in nor do they possess endoapertures. The pseudocolpoid depressions found some species of Crypteronia are only defined by a sculptural differentiation and probably have no

thinned exine.

In the description of the bilaterally flattened Crypteronia pollen grains the following and the of the terms measurements are used. The long equatorial axis, connecting centres

endoapertures, is called EI; the short equatorial axis at right angles to EI is called E2. The

shape is further defined by the outline in lateral view when facing the mesocolpium, the outline in median view when facing the endoaperture, and the outline in polar view. P is

the polar axis. The shape ratio's and respective are P/EJ, P/E EJ/E . 2 2

The following discussion ofthe subdivision of the exine is mainly based on observations

made with the TEM. The small size of the pollen grains made it virtually impossible, with

the exception of the somewhat larger Rhynchocalyx grains, to observe the details with the and also the could that subdivision LM, SEM only suggest a was present. Unfortunately, the Alzatea for the fine sample was not suitable TEM studies and structure of this pollen unknown. type remains

The subdivision of the the and to be exine in Dactylocladus- Crypteronia-type proved

similar. The subdivision to be between less electron-dense basically main appears an inner, electron-dense the layer, equivalent to the endexine s. str., and an outer, more layer, of ektexine, which in its turn can be subdivided into a footlayer, a layer columellae, and

an outer tectum. The thickness of these layers varies between mesocolpia and apertural

areas. The endexine be thickest the thickness appears to near endoapertures, decreasing in towards the mesocolpia, but it is occasionally also relatively thick under the pseudocolpi.

The endexine generally shows a finely granular structure.

The inner boundary of the footlayer is smooth and distinct, but the outer one is rather J. Muller: Pollen morphology of Crypteroniaceae 277

and be delimited from the often broadened basal of the irregular can only arbitrarily parts it columellae. The footlayer is generally thickest on the mesocolpia. Near the colpi appears

to be reduced and changed from a homogeneous structure into a granular (Dactylocladus) clear these or into a lamellar structure ( Rhynchocalyx, Crypteronia). It is not quite in genera

whether the footlayer is also reduced under the pseudocolpi. In Axinandra the footlayer

reduced absent both under and pseudocolpi. appears or colpi The columellate layer in Axinandra is formed by rather widely and regularly spaced

short columellae only, but in Dactylocladus, Rhynchocalyx, and Crypteronia the columellae transitional small are variable in shape and size, and are interspersed withand to granules.

These granules are best developed in Dactylocladus and Rhynchocalyx, where they are

with surface. In concentrated in the outer zone, partially fusing the lower tectum Crypter- and onia only weak evidence for the presence of granules could befotmd. Both columellae

granules are reduced or absent on the colpus membranes. On the pseudocolpi they are

entire reduced but probably present over the membrane.

outer The tectum is generally homogeneous with a more or less irregular inner and

Axinandra in surface. In and Dactylocladus it has a rather smooth surface, but Crypteronia centred and Rhynchocalyx it is more irregular with perforations in the depressions. In This is Rhynchocalyx the tectum dissolves into separate granules near the apertures. less

in is noticeable Crypteronia, where the tectum absent on the colpus membrane and dissol- ved the into separate verrucae on pseudocolpoid areas. Axinandra the In tectum is probably still present as a very thin membrane on the colpi and clearly present on the pseudocolpi.

In and the be less Dactylocladus Rhynchocalyx tectum appears to more or continuous,

although much thicker on the mesocolpia and probably absent in the centre of the colpi. these Detailed studies, preferably of fresh material, are necessary to verify preliminary observations on the fine structure of the wall. Untill then, an evaluation of the differences

found between the genera is not advisable.

SYSTEMATIC DESCRIPTION

subfamily CRYPTERONIOIDEAE

CRYPTERONIA BL.

section Crypteronia

Crypteronia paniculata Bl.

Pi. I: 1—5; Pi. II: 1—4; Ph VI: 1—4. var. paniculata

BANGLADESH. Material studied. Chittagong: King's Coll. 233. —JAVA: Koorders 4335; Schiffner 2283.

var. affinis

Material studied. BURMA. Mergui: Griffith & Heifer 2312/1.

Pollen outline grains spindle shaped, bisyncolporate, equatorial elliptic, Ej/E 2 1.52, rounded lateral outline apiculate-elliptic, P/Ej 0.71, median outline quadrangular with The sides caused the concave sides, P/E2 1.09. concave are by invaginated colporate Size: aperture and pseudocolpoid depressions. P8(8.2) 8.4fim, Ej 11 (11.4) 12 E . /urn, 2

. . rather wide 7 (7.5) 8/tm. Colporate aperture deeply invaginated, ± o.5 ( ttm at bottom, closed by a smooth membrane(Pl. II, 2) which is sharply outlined against the irregularly

verrucate and raised border of the mesocolpium. Equatorial bridges present (Pl. II, 3), 278 BLUMEA VOL. 22, No. 2, 1975

endoapertures indistinct. Mesocolpia with elliptic pseudocolpoid depressions. The exine is, on TEM evidence, subdivisible into outer tectum, layer of columellae, and footlayer, which are all electron-dense, and an endexine s. str. which is less electron-dense. The

is 0.2 for occasional The outer surface is tectum fim thick, massive, except perforations.

on borders of 0.01—0.2 in diameter. Between these irregularly pitted mesocolpia, pits /am border areas and the pseudocolpoid depressions the tectum surface is almost smooth. The pseudocolpoid depressions are again rather densely pitted or subverrucate (Pl. II, 1). The inner surface of the is flat but dissolves into tectum fairly separate granules on the pseudo- colpoid depressions (Pl. VI, 1). The tectum is absent on the colpi (Pl. VI, 1).

The columellae diameter and most distinct the are 0.1/tm long, 0.05 /rm in are in intercolpate areas, while they are reduced inthe pseudocolpate areas.There is someevidence that also this The columellae absent the separate granules are present in layer. are on colpi.

The is thick in footlayer 0.1—0.2 /tm the intercolpate and pseudocolpate areas, away from the the at equatorial zone. It is reduced in colpate areas and lamellated the endo- apertures (Pi. VI, 2).

The endexine str. is probably as a m thick in the endo- s. present o. I /t granular layer apertural but is <0.1 thick in the remainder. areas, /tm is characterized medianoutline Comments. C. paniculata by the alrpost square and the rather distinct pseudocolpoid depressions.

section Basispermia Niedenzu

Crypteronia cumingii (Planch.) Planch, ex Endl.

PL Pi. I: 6—10; PI. II: 5—8; HI: 1 & 2.

Material studied. PHILIPPINES: Mendoza 18241.

Pollen outline grains bilaterally flattened, bisyncolporate, equatorial elliptic, EJ/E2 1.64, lateral outline apiculate-elliptic, occasionally heteropolar with one side more convex than

8 the other, medianoutline rounded quadrangular, P/E 1.14. Size: P (8.5) 9 P/Ej 0.70, 2 /tm,

12 E 8 nar- E, (12.1) 13 /tm, 2 7 (7.4) /tm. Colporate aperture fairly shallowly invaginated,

0.2 wide (Pi. II, 7), closed by a smooth membrane bridged. row, /tm (Pi. II, 8), equatorially

Endoapertures distinct, elliptic in wide in 2 in polar outline, 4/tm equatorial direction, /tm flat direction (Pi. I, 9). Mesocolpia or invaginated, but without clearly differentiated

areas. Exine structureless, thinner at the centre of the pseudocolpoid 0.5 /tm thick, slightly thicker the borders of the surface smooth colporate aperture, slightly at mesocolpia, to slightly and irregularly verrucate-pitted.

Comments. The sections & LM (PL. II, 7 8) show a homogeneous structure ofthe the exine; narrow ektoaperture which is V-shaped in cross section, and the lack of any distinct the pseudocolpoid structure are visible. Upon shrinkage major part of the meso- colpium is invaginated as a whole.

Crypteronia griffithii C. B. Clarke

PI. Ill: 3 & 4.

MALAY PEN. Material studied. Malacca: Griffith s.n.

Pollen outline grains bilaterally flattened, bisyncolporate, equatorial elliptic, EJ/E 2 1.80, lateral outline median outline rounded quadrangular, P/E apiculate-elliptic, P/EJ 0.65, 2

Size: P 7 (7.9) 8 E 11 (12.2) E 6 (6.8) Colporate 1.17. /tm, x 13 /tm, 2 7/tm. aperture equatori- ally bridged, endoapertures indistinct. Mesocolpia with fairly large, elliptic, pseudocolpoid Muixer: J. Pollen morphology ofCrypteroniaceae 279

surface smooth verrucate the borders of depressions. Exine 0.5 thick, to slightly along the ektoapertures, but densely and distinctly verrucate-areolate on the pseudocolpoid

in diameter. depressions, verrucae 0.2—0.3 /Am

Comments. The wide pseudocolpoid depressions with a distinct verrucate surface

the of the sculpture appear to be most characteristic feature pollen of this species. On

Pi. Ill, 3, narrow threads are seen, connecting three grains approximately at the centres of their endoapertures, possibly indicating a tetrad position in which these apertures were in connected two by two a square configuration.

Crypteronia macrophylla Beus.-Osinga

Pi. Ill: 5—8.

Material studied. . Sarawak: Ashton S19607 & S19621; Ilias Paie S24282; Sibat ak Luang

Endert S22356. — Kalimantan: 4040; Amdjah & Nieuwenhuis 301.

Pollen outline E grains bilaterally flattened, bisyncolporate, equatorial elliptic, x/E 2 1.69, lateral outline apiculate-elliptic, P/E median outline rounded quadrangular, P/E x 0.71, 2

1.18. Size: P 8 E 11 E 6 8 (9.0) 10/tm, x (12.9) 14/tm, 2 (7.6) /um. Colporate aperturesnarrow, invaginated and equatorially bridged. Endoapertures indistinct. Mesocolpia without any

differentiated but often Exine structurally pseudocolpoid area, invaginated. o.j /mi thick, surface rather verrucate. in 0.1—02. entirely, densely Verrucae 0.2—0.3 fim diameter, /mi high. The which the Comments. densely verrucate sculpture, is beyond resolving power of the light microscope, is the most typical feature of the pollen of this newly described species.

DACTYLOCLADUS OLIV.

Dactylocladus stenostachys Oliv.

Pi. I: 11—14; PI. IV: 1—3; PL VIII: 1—4.

Material studied. BORNEO. Brunei: Ashton Brun. 280.

rounded Pollen grains spherical-subprolate, P/E 1.04, equatorial outline hexangular, heterocolpate with three colporate apertures alternating with three pseudocolpi. Size:

medium P 12 (13.2) 15/«n, E 12 (12.7) 14 /mi. Colporate ektoapertures are long (PI 0.4), and into the slighdy invaginated, equatorially bridged passing very gradually surrounding

mesocolpia; their outer surface is smooth or irregularly verrucate. The equatorial bridges

and exine is are rather irregular not very pronounced (Pl. IV, 2), the thinner here and the ill defined. The similar underlying endoapertures are irregular and pseudocolpi are rather

and the that are not in size general appearance to colporate apertures,except they equatori- in their On the ally bridged and have a more distinct verrucate sculpture centre (Pl. IV, 1). Pl. visible the section shown on IV, 3, the rather deeply invaginated pseudocolpus is in the central of the folded covered with upper part, part area being partly densely spaced

0.2 in diameter. verrucae —0.4 fj.m The subdivisible of and exine is, on TEM evidence, into outer tectum, layer columellae,

footlayer, all relatively electron-dense, and an inner endexine s. str. which is less electron-

dense.

The thick the the tectum is up to 0.25 /im on mesocolpia, decreasing to 0.1 /um near continuous is colpi, and forms a nearly layer. Its outer surface smooth or slightly uneven whole surface of near the colpi, due to undulations of the layer. The inner the tectum is smooth and or slightly irregular it appears to be much reducedand possibly locally absent

over the ektoapertures and pseudocolpi. 280 BLUMEA VOL. 22, No. 2, 1975

The columellae are o.io—0.15fim long, 0.10—0.05 fim in diameter, irregularly shaped, best developed and widely spaced on poles and mesocolpia; elsewhere they have an

irregular granular appearance. Interspersed with the columellae, separate granules 0.025— diameter attached the 0.05 fim in are present, mostly to innertectum surface, or gradually it is merging with as visible on the oblique section (Pi. VIII, 3). Both columellae and

granules are very much reduced near the apertures, but probably do not disappear com- pletely.

The is to thick the and decreases in footlayer up 0.3 /rm on intercolpate areas gradually thickness the where it consists of isolated to 0.02/tm near apertures, granules and some-

times faintly shows a lamellate structure (Pi. VIII, 1).

The endexine is o.I thick and and in s. str. fim homogeneous on mesocolpia increases thickness the where Under the to 0.25 fim near endoapertures it shows a granular structure. thick and be pseudocolpi it is 0.2 fim appears to homogeneous.

AXINANDRA THWAITES

Axinandra beccariana Baill.

Pi. I: 15—17; Pb IV: 4 & 5! Pi- VI: 5.

Material studied. BORNEO. Sarawak: Brain ak Tudo S13909.

Pollen grains spherical-subprolate, P/E 1.04, equatorial outline rounded hexangular, heterocolpate with three colporate apertures alternating with three pseudocolpi. Size: P (14.6) E Colporate ektoapertures long (PI 0.25), invaginated 13 15 /tm, 13 (14.1) 15 /tm. are and the equatorially bridged (Pi. IV, 5). They pass gradually into mesocolpia, are fairly wide while at the equator, their tips are pointed and indistinctly outlined. Their surface is smooth to finely the scattered being 0.2 in diameter. The verrucate, verrucae ± /tm show membrane The endo- equatorial bridges may a protruding aperture (Pi. IV, 4). the diameter apertures, underlying equatorial bridges, are irregularly shaped, 2—3/am in with indistinct outline. The do reach far an pseudocolpi are elliptical in outline and not as towards the the poles as colporate apertures (Pi. IV, 5). They are more or less invaginated, depending on the state of shrinkage of the grain and dieir surface is densely verrucate.

The verrucae are in diameter. ± 0,2 fim

TEM evidence indicates subdivision of the exine into a relatively electron-dense outer

of which less tectum, layer columellae, and footlayer, and an inner endexine s. str. is electron-dense.

The thick the thickness tectum is 0.3 fim on mesocolpia, decreasing in to 0.1 /tm near the edge of the apertures. It is probably still present as a very thin layer both on the mem- branes closing the colpi as well as the pseudocolpi. The outer surface is smooth, with isolated small diameter but the membranes of the verrucae 0.1 fim in on mesocolpia, on pseudocolpi these verrucae are more prominent and densely spaced. The columellae in show are 0.05 —0.10 /tm long, 0.01—0.20 /tm diameter, a concave profile and are regularly spaced. the but still They disappear near colpi appear indistinctly the present on pseudocolpi. The thick thickness towards the footlayer is 0.3 /tm on mesocolpia, decreasing in edge of the and is absent and The surface is apertures, probably on colpi pseudocolpi. upper smooth to slightly irregular, the inner boundary smooth. The endexine has thick the s. str. a homogeneous appearance, is 0.05 fim on mesocolpia, thick the and under the 0.3 on colpi, 0.2 fim pseudocolpi. Comments. The shown be covered with grain on Pl. IV, 5 appears to partly J. Mulled: Pollen morphology of Crypteroniaceae 281

extraneous acetolysis-resistant globulate material which may have been derived from the tapetum and could represent clustered Ubisch bodies, secondarily attached to the exine surface during maturation.

subfamily ALZATEOÏDEAE

ALZATEA RUIZ & PAV.

Alzatea verticillata Ruiz & Pav.

PI. I: 18—20; PI. IV: 6—9.

Material studied. PERU. Ule 6750.

Pollen grains spherical-subprolate. P/E 1.05, equatorial outline rounded, triangular, tricolporate, rarely bicolporate. Size: P 17 (17.9) 19/urn, E 15 (16.9) 19fim. Ektoapertures distinct, invaginated and equatorially bridged (PI 0.30), closed by a flat, slightly and

verrucate and with Their sides rather irregularly membrane, pointed tips (Pl. IV, 6). are distinctly outlined by the raised, irregularly verrucate borders of the mesocolpia (Pl. IV,

The is shown in Pl. the 7). equatorial bridge close-up on IV, 9: in its centre apertural mem- brane protrudes slightly. The endoapertures, underlying the equatorial bridges are developed as irregular-circular thinned areas on the inner side of the exine, with a fairly distinct outline, in diameter. (Pl. I, 20). Exine homogeneous indistinctly 3—5 /

in 6 & larly pitted or, especially the centre of the mesocolpia (Pl. IV, 7), irregularly ver- rucate-areolate. The in diameter and shallow. pits are funnelshaped, ± 0.1—0.4 jum very The and be verrucae are often ill-defined could consideredas irregular elevations separating the the of pits; only in centre the mesocolpia they are more distinct, densely spaced, with a diameter to while the here less up 0.4 fjtm, pits are prominent. the Comments.Lourteig (1965) describes exine of.Alzatea pollen as finely reticulate, but the SEM is on photomicrographs shown here, no trace of such a sculpture type seen. of The presence a slight differentiation in sculpture in the centre of the mesocolpia, as

of well as the fact that the equatorial outline the grain also sometimes shows slight in- the of vagination here, is interesting in suggesting incipient development a pseudocolpoid structure.

RHYNCHOCALYX OLIV.

Rhynchocalyx lawsonioides Oliv.

PI. V: Pi. 1—11; VII: 1—3.

Material studied. S. . Natal: Slrey 6539.

Pollen grains spherical-subprolate, P/E 1.08, equatorial outline rounded hexangular, with three with three heterocolpate colporate apertures alternating pseudocolpi. Size: P 19(19-6) 20fim,E 17 (18.1) 19 /um. Colporate ektoapertures long (PI 0.20), invaginated, without with indistinct shown Pl. the or equatorial bridges. As on V, 7 & 8, aperture has membrane a rather densely andfinely verrucate surface and as such is rather dinstinctly outlined against the mesocolpia. The tips of the ektoapertures are narrow and rather distinctly outlined. The endoapertures are ellipsoidal areas in which endexine appears absent direction and direc- (Pl. V, 2, 9); they measure 3 fxm in equatorial 1.5 [im in polar tion. They may also be developed as two circular areas separated by an equatorial bridge The similar and the (Pl. V, 10). pseudocolpi are in size general appearance to colporate apertures and can only be differentiated by their lack of endoapertures. BLUMEA VOL. No. 282 XXII, 2, 1975

LM SEM threefold subdivision of the but TEM and already suggest a exine, clearly the into shows presence of an electron-dense outer layer, differentiated a tectum, a layer which less electron-dense. of columellae, and a footlayer, and an inner endexine s. str. is visible The latter layer is not clearly on the fuchsin stained LM micrographs of sections shown on Pl. V, 4 & 5. The The tectum is with a outer surface. 0.3 fxm thick, shallowly pitted verrucate the The individual vcrrucae are 0.1—0.5 /xm in diameter, pits are < 0.2 /um deep. inner boundary of the tectum is rather irregular. The tectum is absent in the centre of the

but into in the colpi, appears to dissolve separate granules, 0.1 —0.05 fx m diameter, on membranes of the pseudocolpi (Pl. VII, 3).

The columellae in diameter. A of are 0.3 fim long, 0.05—0.1 [xm layer granules 0.05 fim

be of the columellate at- in diameter appears to present in the outer zone layer, partly the tached to the inner side of the tectum. Over apertural areas the columellae are much

still reduced or absent altogether, although a few granules may be present, suggesting continuity.

The thick and the but reducedto footlayer is up to 0.3 fim homogeneous on mesocolpia,

less over the areaswhere to be of electron-dense 0.1 fim or colpate it appears composed the lamellae of thickness .The is probably also reduced at <0.05 fim (Pl. VII, 1) footlayer pseudocolpi.

The endexines. str. is clearly visible onPl. VII, 2 as a granular deposit 0.8/rm thick under- the direction of the the neath the colporate apertures, gradually thinning in mesocolpia, in

it be absent. It is absent underneath the centre of which may probably pseudocolpi.

DISCUSSION

From the preceding descriptions it will be clear, that the pollen grains of the five which genera are comparable in: small size, long ektoapertures may be equatorially bridged and generally are provided with small endoapertures, thin exine with a similar surface. The structural differentiation and a smooth or finely verrucate to pitted principal

in the of the and in the and of differences are symmetry apertures, shape development the The main pseudocolpi or pseudocolpoid areas on centres of the mesocolpia. problem is, Beusekom's whether pollen morphology can provide arguments pro or contra Van inclusion of all first of five genera in Crypteroniaceae. At sight, course, a major gap appears and to exist between Crypteronia on one hand the remainder of the genera on the other. bilateral Since no transitions could be observed between the bisyncolporate Crypteronia- difficult derive type and the heterocolporate triradiate Dactylocladus-type, it appears to these from each other. to derive both two pollen types directly However, it is possible

from ancestral which close to the Alzatea- and types a common, tricolporate type, is type this is schematically shown in fig. I. The of the defined and three symmetry tricolporate type is by one equatorial polar of towards the involves in planes symmetry. Change A, heterocolpate type no change of oriented symmetry, but merely the addition three, meridionally pseudocolpi.

Guers (1970) has established that, within the genus Rotala (Lythraceae), species occur which are characterized respectively by three colporate apertures, by three colporate apertures with three indistinct pseudocolpi, and by three colporate apertures with three distinct pseudocolpi, while in Rotala mexicana differing degrees of heterocolpateness where found by Coz Campos (1964). Moreover, in Alzatea faint traces of incipient pseudocolpi are visible, approaching the condition of some Rotala species with indistinct the scheme pseudocolpi. All this would indicate that change A as depicted in is not in- conceivable. J. Muixer: Pollen morphology of Crypteroniaceae 283

Relations between in view view lower- Fig. 1. pollen types Crypteroniaceae (polar uppermost, equatorial most).

Change Bi towards a spherical, bisyncolporate grain involves a decrease in aperture from three of and fusionof the symmetry to two polar planes symmetry a two apertures the known at poles. Similar transitions are from Phyllonoma integerrima (Saxifragaceae; cf. and cf. Erdtman, 1952, fig. 231) Crossosoma californicum (Crossosomataceae; Erdtman, In Alzatea In all these both 1952, p. 133). bicolporate grains occur very rarely. cases and Such reduction number of tricolporate bicolporate grains are present. a in apertures has shown therefore appears to be a not uncommon phenomenon. Huynh (1968) that this

be caused in orientationof the two of in the may by a change couples sister-microspores

post-meiotic tetrad with respect to each other and this is not considered a fundamental of change. The transitions to syncolpate grains are also regularly observed in some these

cases. 284 BLUMEA VOL. 22, No. 2, 1975

The final step (Bz), towards the Crypteronia pollen type, involves firstly the develop- ofbilateral of the ment shape symmetry by means flattening parallel to apertural symmetry axis. plane and, secondly, a relative shortening of the polar It will be obvious that the change from tricolporate to bicolporate has preceded, or occurred simultaneously with, the in The fact that in the listed such change shape. taxa above, an apertural change may occur without a change in shape, suggests that the former is primary, however. Thirdly,

in orientation pseudocolpoid depressions equatorial may develop. Here the question how the arises, in far these are comparable to pseudocolpi found in the Dactylocladus- is clear from the the construction of both the type. As descriptions, appears similar, only orientation is in equatorial Crypteronia, meridional in Dactylocladus. Functionally they are doubt both additional and no comparable, acting as harmomegathic structures as such they represent specializations in comparison with the postulated simple ancestral tricol- that oriented porate type. It will also be obvious a meridionally pseudocolpus is difficult to visualize in Crypteronia pollen and their equatorial orientation is structurally only to be expected. In the sense that in both cases they have originated from the centre of the

be considered and their otherwise mesocolpia, they may homologous, appearance in shown diverging lineages, as in fig. i, suggests independent, parallel development. thus that the differences between the three It appears in symmetry pollen types may not be fundamental and can be explained as a case of diverging evolution. This, added to the obvious similarities in exine and aperture structure, supports the inclusion of the five generain Crypteroniaceae. The wider affinities of Crypteroniaceae remain to be discussed, as far as they are expressed in the pollen morphology. The relatively unspecialized Alzatea-type is widespread in many dicotyledonous families. It occurs in Lythraceae, in which Alzatea was placed by

the Lourteig (1965), in genera Adenaria, Pemphis, Pehria, Pleurophora, Physocalymna, in It is known Woodfordia, and some species of Rotala. also from several other families of the Myrtalean alliance (Punicaceae, Lecythidaceae, Rhizophoraceae, Combretaceae).

The more specialized Dactylocladus- type is less widespread in Lythraceae and occurs

in in only Lythrum, Peplis, and some species of Ammania, Nesaea, and Rotala. It is, however, also the dominant and Oliniaceae. pollen type in Melastomataceae, Combretaceae, ,

These families to be related appear closely on macromorphological grounds.

The Crypteronia-type, as befits a fairly specialized pollen type, is more difficult to relate to other families. Erdtman (1952) has stated that Crypteronia pollen is similar to that found in Corynocarpaceae, Cunoniaceae (Belangera, Geissois), Eucryphiaceae, and Saxifragaceae normal (Bauera). In Bauera and Geissois the bicolporate grains are variants of tricolporate subprolate grains and no relations are indicated. The characteristic bilaterally flattened

the shape of Crypteronia-type does, however, occur in the other taxa mentioned by Anodo- Erdtman and, as I was recently informed by Dr. M. Hideux, also in Platylophus, petalum, Ceratopetalum, and Schizomeria (Cunoniaceae). In the latter genera a marked structural modification of the mesocolpium is also found, which is, perhaps, comparable the to the pseudocolpoid depressions found in Crypteronia pollen. On the other hand, finely reticulate wall foundin the pollen grains of Cunoniaceae and Eucryphiaceae militates against a very close relationship. Erdtman's and of between (1952) Takhtajan's (1959) suggestions a relationship Cryp- Cunoniales teronia and thus cannot be ruled out, although it may only be a remote one.

In detailed future, comparisons of the fine structure of exine and aperture may yield decisive evidence.

In this connection, the interesting geographical distribution of the family, as con- ceived by Van Beusekom and of its pollen types should also be mentioned. Alzatea only J. Muller: Pollen morphology of Cryptcroniaceae 285

in Amazonian of S. be ancient occurs the region Peru, America, and may an relic. The

Dactylocladus pollen type occurs in Rhynchocalyx, a local endemic of South Africa, and in

Asiatic the the genera Axinandra and Dactylocladus. Finally, advanced Cryptcronia pollen

is restricted SE. and endemic type to suggests a young development.

CONCLUSIONS

The present day lack of pollen morphological transitions between the pollen types within s.l. would first dismiss likelihood of a Crypteroniaceae at sight tempt one to any close taxonomic relationship. However, the fact that the three pollen types recognized can be arranged in an evolutionary scheme, as well as the pronounced similarities in and fine Beusekom's delimitation of the aperture exine structure, support Van family. His recognition of two subfamilies is not expressed in pollen morphology, the Dactylo- cladus both. pollen type occurring in the be that At same time it must stressed pollen morphology provides no unique character separating Crypteroniaceae s.I. from other related families. Similar, if not iden- tical, pollen types occur in Punicaceae, Lythraceae, Melastomataceae, Combretaceae, Oliniaceae, and Penaeaceae and this is supporting macromorphological and anatomical evidence. A

Cunoniaceae the is more remote relationship to suggested by Crypteronia pollen type also indicated but by macromorphology not by anatomy. A relationship to Sonnera- tiaceae is improbable since their pollen grains are entirely different (Muller, 1969).

REFERENCES

F. BBUSEKOM, C. VAN, 1975. Morphology and relationships of Crypteroniaceae s.l. Blumea 22:

BEUSEKOM-OSINGA, R. J. VAN & C. F. VAN BEUSEKOM, 1975. Revision ofCrypteroniaceae. Blumea 22: Coz D. £tude Perou. CAMPOS, 1964. des grains de pollen des Lythracees du Pollen et Spores 6: 303 —345.

R. Studies Penaeaceae, VI. The L. Botanica 1 DAHLGREN, 1971. on genus Opera 29: —58. G. Pollen and Notes families. Svensk ERDTMAN, 1946. morphology . VII. on various Bot.

Tidskr. 40: 77—84.

— Pollen and Introduction 1952. morphology plant taxonomy, Angiospcrms (An to Palynology I).

GUERS, J. 1970. Palynologie Africaine X. Bull. I.F.A.N. 32: 312 —365.

K. HUYNH, L. 1968. £tude de L'arrangement du pollen dans la tdtrade chez les Angiospermcs sur la base de

donnees cytologiques. Bull. Soc. Bot. Suisse 78: 151—191.

A. the R. P. Ann. Missouri Bot. LOURTEIG, 1965. On systematic position of Alzatea verticillata & Gard. 52:

371—378.

A Sonneratia Pollen MULLER, J. 1969. palynological study of the genus (Sonneratiaceae). ct Spores 11:

223 —298.

— K. Grana 1973. Pollen morphology of Barringtoniacalyptrocalyx Sch. (Lecythidaceae). 13: 29—44.

TAKHTAJAN, A. 1959. Die Evolution der Angiospermen. of VLIET, G. J. C. M. VAN, 1975. Wood anatomy ofCrypteroniaceae in the wide sense. Journ. Microsc. no: P. — of s.l. Blumea & BAAS, 1975. Comparative anatomy Crypteroniaceae 22: BLUMEA 286 VOL. 22, No. 2, 1975

Plate I. — Fig. I—5. Crypteronia paniculata. 1. King's Coll. 255, polar view, U.F.; 2 & 3. Schiffner 2285, and lateral polar view, same grain, U.F. L.F.; 4. Griffith & Heifer 2512/1, view, U.F.; 5. Schiffner 2283, median view, L.F. — Fig. 6—10. Crypteronia cumingii, Mendoza 18241; 6. Polar view, U.F.; 7. Lateral view,

L.F.; 8. Lateral section; 9. Median view, U.F.; 10. Median section, Ph. C. — Fig. 11—14. Dactylocladus

Ashton Brun. & stenostachys, 280; 11 12. Polar view, same grain, U.F. and L.F.; 13. Hquat. section, Ph. C.;

14. Equat. view, U.F. — Fig. 15—17. Axinandra beccariana, S 15909; 15. Polar view, U.F.; 16. Polar view,

U.F. — 18—20. 18 L.F.; 17. Equat. view, Fig. Alzatea verticillata, Ule 6750; & 19. Polar view, same grain,

and — All U.F. L.F.; 20.Equat. view, U.F. x 2000, O.I.

II. — Plate Fig. 1-—4. Crypteronia paniculata. 1. King's Coll. 235, lateral view, x 2500; 2—4. Griffith & Heifer

Polar Polar and Polar — —8. 2512/1; 2. view, x 5000; 3. apertural view, x 5000; 4. view, x 5000. Fig. 5

6. section Crypteronia cumingii, Mendoza 18241; 5. Lateral view, x 5000; Polar view, x 5000; 7. Median and

8. Median section end and — All: oblique polar view, x 5000; at apertural oblique polar view, x 5000. SEM.

III. — & Plate Fig. 1 2. Crypteronia cumingii, Mendoza 18241; 1. Median section, x 5000; 2. Median section, x 5000. -— Fig. 3 & 4. Crypteronia griffithii, Griffith s.n.; 3. Lateral view, x 5000; 4. Lateral view, x 5000. —

—8. 6. Fig. 5 Crypteronia macrophylla, Endert 4040; 5. Lateral view, x 5000; Lateral view, x 5000; 7. Polar view, x 5000; 8. Oblique polar view, x 5000. — All: SEM.

IV. — Brun. Plate Fig. 1 —3. Dactylocladus stenostachys, Ashton 280; 1.Polar and equat. view, x 2500; 2. Equat.

— Axinandra S Polar view, x 2500; 3. Equat. section, x 3500. Fig. 4 & 5. beccariana, 15909; 4. view, x 2500;

— 6 Ule 6. 5. Equat. view, x 2500. Fig. —9. Alzatea verticillata, 6750; Polar view, x 2500; 7. Oblique polar

view, x 2500; 8. Equat. view, x 2500; 9. Aperture, x 3500. All: SEM.

Plate V. — Fig. 1 —11.Rhynchocalyx lawsonioides, Strey 6539; 1. Polar view; 2. Equat. view of endoaperture; _ _ _ view 3. Equat. ofpseudocolpus; 4. Equat. section; 5. Meridional section; 6. Inner view of endoaperture;

view of left and 8. centred 7. Equat. colporate aperture at pseudocolpus at right, x 2500; Equat. view on

x Interior view of colporate aperture, 2500; 9 & 10. endoaperture, x 2500; n. Interior polar view, x 10.000.

— 1—6; LM, x 2000, O.I.; 7 —11.SEM.

Plate — Coll. VI. Fig. 1 —4. Crypteroniapaniculata, King's 23S; X- Oblique section, at top rightcomer through endoaperturalregion, at bottom through ektoaperture on pole (c) and at left through pseudocolpoid area

x Detail of of Meridional (pc), 10.000; 2. fig. I showing granular-lamellarstructure endexine, x 25.000; 3.

section approximately through centre of pseudocolpoid areas, polar sections of ektoaperture at bottom

x and — right top left, 10.000; 4. Oblique section throughpseudocolpoid area at bottom, x 10.000. Fig. 5.

Axinandra S section at bottom and beccariana, 15909, equat. throughpseudocolpus colporate aperture at left,

x 10.000.— i—5: TEM.

VII. — Plate Fig. 1—3. Rhynchocalyx lawsonioides, Strey 6539; 1. Oblique section through endoapertural

x section region, 20.000; 2. Equat. through endoapertural region at top, pseudocolpus at right, x 10.000;

3. Equat. section, colporate apertures (c) alternating with pseudocolpi (pc), x 10.000. — All: TEM.

Plate VIII. — Fig. 1—4. Dactylocladus stenostachys, Ashton Brun. 280; I. Oblique section throughintercolpate

area, x 20.000, detail of fig. 2; 2. Oblique section, colporate aperture (c) and pseudocolpus (pc), x 10.000;

section in 3. Tangential throughintercolpate exine, tectum centre, footlayer at periphery, x 20.000; 4. Equat.

section, colporate apertures (c) alternating with pseudo-colpi (pc), x 10.000.— All: TEM. J. Muller: Pollen morphology of Crypteroniaceac 287\I

Plate I 288\II BLUMEA VOL. 22, No. 2, 1975

Plate II J. Mulleh: Pollen morphology of Crypteroniaceae 289\III

Plate III BLUMEA VOL. 290\IV 22, No. 2, 1975

Plate IV J. Mulleh: Pollen morphology of Crypteroniaceae 291\V

Plate V 292\VI BLUMEA VOL. 22, No. 2, 1975

Plate VI J. Muller: Pollen morphology ofCrypteroniaceae 293\VII

Plate VII BLUMEA VOL. 294\VIII 22, No. 2, 1974

Plate VIII