Kew Bull Research Articles

The Genus Plagiopteron (Plagiopteraceae) Recorded for Thailand

Plagiopteron fragrans Griff in Calcutta Journ. Nat. Hist. 4: 244, t. I3 (1843); Steud. in Flora (Ratisb.) 27: 437 (1844); Walp., Rep. 5: 370 (1845); Bocquillon in Adansonia 7: 30-32, 35 (1866); Muell. Arg. in DC., Prodr. 15(2): 126o (1866); Airy Shaw in Kew Bull. 18: 266 (1965), q.v. for further synon. and discussion, and in Willis, Dict. Fl. PL., ed. 8: 9Io (1973). Described from a plant growing in the Calcutta Botanic Garden, 'said to have been introduced from Sylhet [Assam] in 1829'. Specimens also in Herb. Kew. collected by Griffith in Mergui (Tenasserim, Lower Burma).

Notes on African Rubiaceae: Leptactina and Cuviera

The following notes result from continuing work on the family Rubiaceae in connexion with the second volume of this family for the 'Flora of Tropical East Africa'. As mentioned previously (Kew Bull. 31: 181 (1976)) it has been considered advisable to publish work as completed so that names are available. All cited specimens have been seen unless otherwise indicated. Subdivisions of Uganda, Kenya and Tanzania are given as in Flora of Tropical East Africa, and of Mozambique, Malax^ i, Zambia and Rhodesia as in Flora Zambesiaca.

THE LATIN NAME OF THE ‘PADRI’ TREE (BIGNONIACEAE)

In my review of the Commentaries of Francis Hamilton (Taxon 26: 523-540, 1977), I wrote that the plate, Rheede, Hort. mal. 6, t. 26 ['Padri'] = ? Stereospermum chelonoides (L.f.) DC. The confusion over this latter name has been recently displayed (see Kew Bull. 28: 178, 1973) and the padri is currently known as S. personatum (Hassk.) Chatterjee, based on Dipterosperma personatum Hassk. (1842). As I showed in my paper, an earlier name is Bignonia colais [Buch.-Ham. ex] Dillw. (1839), Dillwyn noting, Quoted by the younger Linnaeus, and generally by other authors, for B. Chelonoides, but was considered by Dr. Hlamilton [in his MSS now at the Linnean Society] to be a separate species:

Studies in Elionurus (Gramineae)

Elionurus Willd. is a genus of the tribe Andropogoneae, with solitary spikes and unawned lemmas. Its circumscription has been discussed by Clayton in Kew Bull. 20: 258 (1966). It comprises 15 species, found in the tropics and sub-tropics of Africa, America and Australia. Considerable difficulty is found in distinguishing the more widespread species which vary a great deal in some parts of their ranges. For example in Africa E. tripsacoides, E. ciliaris and E. muticus may be readily distinguished by their simple or branched culms and glabrous or densely ciliate spikelets. In America however these significant features are not so clearly defined and often overlap in their range of variation, a situation which suggests that introgression may be occurring between these three species. This brief review is intended to draw attention to the problems in the taxonomy of this genus, which will probably require breeding experiments before they can be solved satisfactorily. At the present time Dr. C. Quarin at Corrientes, Argentina, is investigating the breeding behaviour of the S. American species and hopefully his work will help to clarify the taxonomic relationships between some of the more difficult species.

Notes on Distribution and Biology of Aponogeton ranunculiflorus

This unusual species of Aponogeton was described in I972 (A. Jacot Guillarmod & W. Marais in Kew Bull. 27: 563-565, 1972). As far as was then known the total area in which the plant occurred was 3 hectares and as it grows in rock pools, the actual habitat area was thus much less. Fortunately all the pools containing the plant were within the boundaries of the Sehlabathebe Mountain National Park, Lesotho, and thus well protected. Since then, Mr. P. Cookingham has explored on the Republic of South Africa side of the boundary fence, within about two kilometres of the nearest site in the park, and has found, at the same altitude and in the same type of situation, some pools in Cave Sandstone rock containing the plant. This places the species also in Natal, RSA. In 1976 Dr. F. Hoener, botanist at the park, reported a further find within the boundaries of the park, but at the southern extremity near the border with the Cape Province, RSA. The distribution is thus more widespread than at first thought, but all occurrences are at the same altitude of approximately 26oo m, in Cave Sandstone rock pools and within a Io km distance. Mr. Cookingham further observed that some of the pools may ice up completely during winter so that the plants are frozen into the muddy bottom. Also, at times, the pools may, if shallow, dry up but once filled again by rains and run-off water, the Aponogeton continues growth from the minute corms. The plant thus withstands very varied conditions and a great range of temperatures. In February, 1975, seed collected, with permission from the Park Manager, was sent to the Royal Botanic Gardens, Kew and also to Holland, while some seed and small corms were taken to Grahamstown. In the laboratory, the author has cultivated the plant since then under the following conditions. A glass fish tank capable of giving a depth of about 29 cm of water was filled to within 2 cm of the top with acidic borehole water. This water comes from a borehole in Witteberg quartzite rock and the pH value is within the

The Genus Rhytachne (Gramineae)

Summary. The genus Rhytachne Desv. is reviewed, and a new species, R. latifolia, is described. The status of the genus and its relationship with Coelorhachis Brongn. have previously been discussed by Clayton in Kew Bull. 24: 309-314 (1970), and its West African species have been dealt with by Clayton in Hepper, Fl. West Trop. Africa ed. 2, 3: 509-51 (1972). Difficulties encountered with the east African species have necessitated a re-examination of the genus.

The Generic Position of Vigna speciosa (Leguminosae-Papilionoideae)

In Kew Bull. 24:552 (1970) I transferred Phaseolus speciosus H.B.K. to Vigna, at the same time raising Phaseolus sect. Sigmoidotropis Piper to the rank of a subgenus under Vigna; Piper had indicated that he considered P. speciosus to be the type of his section. My decision to transfer the quite large group of species involved to Vigna was based mainly on style and pollen characters; the pollen grains of this subgenus have the typical coarsely reticulate exine so characteristic of all but a few species of Vigna. Recently Dr. F. Stainer (Note sur le pollen de quelques espeices SudAmericaines du complexe PhaseolusVigna. Pollen et Spores 18(4): 523-531 (1976)) has claimed that the exine sculpture of Phaseolus speciosus is of exactly the same type as that of P. adenanthus G. F. W. Mey, which is the type of Phaseolus sect. Leptospron Benth. As I have previously pointed out, P. adenanthus is peculiar in its pantropical distribution which is clearly linked to its mainly littoral or lowland habitat. Bentham, Comm. Leg. Gen.: 72 (1837), included P. adenanthus in sect. Drepanospron and P. truxillensis H.B.K., now known to be a synonym of P. adenanthus, in sect. Leptospron with P. speciosus and many other diverse species. Later, in his work for the Flora Brasiliensis, these two sections were merged with 'sect. Euphaseolus', i.e. Phaseolus sect. Phaseolus. Piper, Contrib. U.S. Nat. Herb. 22: 673 (1926), included section Leptospron in his key to the sections of Phaseolus but mentions no species; I suggested Leptospron could be typified by Phaseolus truxillensis, i.e. P. adenanthus (1.c. 512). The species seems distinct enough to me to need sectional recognition. This serious divergence of views concerning the pollen sculpture of Phaseolus speciosus is clearly of importance with regard to the classification of the two genera, particularly that of the South America species of Vigna. In order to resolve the problem I wrote to Paris to find out if it would be possible to examine pollen from the holotype of P. speciosus, Humboldt's specimen from the R. Orinoco. The specimen is in poor condition but through the kindness of Dr. Alicia Lourteig I have been able to borrow and examine a single stamen from the dissected flower contained in a packet on the sheet. By soaking in water and mounting in glacial acetic acid the surface sculpture of some of the few pollen grains contained in the anther could be clearly seen without damaging the stamen which has since been returned to the sheet; the exine is definitely coarsely reticulately sculptured and there is no doubt that my original interpretation is correct.

A New Species of Cola (Sterculiaceae) from East Africa

Mr. J. B. Gillett in 1976 sent to me for an opinion some specimens collected in Kenya with the suggestion that they might represent an undescribed species of Cola. This suggestion has indeed proved to be correct. In Kew Bull. 11: I4I-I52 (1956) I published a revision of the species of Cola at that time known from East Africa. The present species is very distinct indeed from all the eleven species described then and is in fact remarkable in several ways. Its significance is discussed below, after the description and citation of specimens.

Some Brief Reflections on C. H. Persoon

Summary. A brief outline is given of Persoon's life and role in the evolution of mycological taxonomy. Much of what is written below has already been aired, but there are two pertinent connexions between Persoon and the Royal Botanic Gardens, Kew, which perhaps permit some additional thoughts-albeit quasi-biographicalto be expressed regarding this famous but little understood 'Prince of Mycologists'. In the first place, there are some Persoon specimens at Kew, and in the second, the recently resurrected water-colour drawings executed for Persoon as the originals for a number of his publications reside at Kew, and have been commented upon by Dr. R. W. G. Dennis (Kew Bull. 29: 7I1-715 (I975)) whom we honour in this volume. The literature below is not exhaustive on Persoon, but represents a number of references which I have seen. Most often, readers have stopped at Lloyd's contributions, which for the most part are extensions of F6e's rendition, but

A Synopsis of the Genus Chazaliella. (Rubiaceae-Psychotrieae)

The genus Chazaliella was first mentioned by Petit in his revision of the African species of Psychotria (in Bull. Jard. Bot. Brux. 34: 23 (1964)) but not formally described. A formal description was given by Verdcourt (in Kew Bull. 30: 267 (I975)) since validation was needed for the account of the genus in Fl. Trop. E. Africa, Rubiaceae, I (1976); new combinations were made for the species at the same time without, it must be admitted, any very detailed study. It seemed advisable that an attempt should be made to revise the genus but the species have proved difficult and are mostly rather featureless and morphologically uninteresting. The preliminary results obtained are recorded here. Miss M. Bywater and Mr. G. P. Lewis have prepared the illustrations and maps, for which I am most grateful.

Additions and Corrections to the Euphorbiaceae of Siam

Recent botanical expeditions in Siam have brought to light a number of taxa, including a new genus and some new species, additional to those listed in my enumeration of the Euphorbiaceae of Siam in Kew Bull. 26(2): 191-363 (1972). These new taxa are described below, together with some new varieties and geographical records. The opportunity has been taken to include also a number of corrections to the existing text. For an explanation of the abbreviations used and a key map to the geographical areas, reference should be made to my original account, pp. 192 and 204-

The Correct Chromosome Number for Crocus medius Balb.

In the list of chromosome counts for the genus Crocus (Brighton, C. A., Mathew, B. F. & Marchant, C. J. in Kew Bull. 28(3): 451-464 (1973)) counts of 2n = 28 and 2n = 30 were reported for two collections of Crocus medius from Monte Alto and the Ligurian Alps in Italy. A more detailed study of the karyotypes has shown that B-chromosomes occur in this species and that one pair of chromosomes has very distinct secondary constrictions giving the impression of two separate chromosomes lying close together when in fact there is only one. The correct numbers for the plants examined are 2n = 24 + 2B and 2n = 24 + 5B respectively. Both karyotypes are illustrated in Figure IA & B and consist of three pairs of median chromosomes, one pair of chromosomes with two secondary constrictions, one pair of sub-median chromosomes and seven pairs with subterminal constrictions. From 2-5 B-chromosomes were also present in the two collections examined. Pair IV of both karyotypes has three distinct constrictions (arrowed). It is uncertain which of these is the centromere, but meiotic studies might give some indication. Chromosomes of this kind are very unusual. If one supposes the centromere to be the central constriction, then there is a possibility that these could be iso-chromosomes similar to those found in Nicandra by Darlington & JanakiAmmal in Ann. Bot. II, 9(35): 267-28 (1945). Here again, meiosis would need to be observed in detail to see whether these chromosomes pair normally, or whether each chromosome consists of identical arms which are capable of pairing together.

A New Combination in Albertisia (Menispermaceae)

In my recent paper on the tribe Triclisieae Diels in Kew Bull. 30: 77-i00 (1975), the African genus Epinetrum Hiern was placed in synonymy under Albertisia Beccari and new combinations for the African species were published. Unfortunately, owing to an oversight in preparation of the final draft of the paper, one new combination was omitted. I am most grateful to Dr. G. Thanikaimoni for drawing my attention to this omission. The new combination concerned is the following:

A Further Note on Lomatophyllum (Liliaceae)

Since writing the notes on 'The extra-Madagascan species of Lomatophyllum (Liliaceae)' in Kew Bull. 29: 721-723 (I975), further information on the Reunion plant has become available and it is now clear that it and the Mauritian species are distinct. Aloe purpurea Lam. was based on a plant growing in the Royal Garden in Paris, said to have come from Rdunion, 'on la dit originaire de l'Isle de Bourbon'-nothing definite. A type specimen, consisting of a leaf and an inflorescence without flowers has been preserved, but is not of much help in coming to a definite decision about the identity of the plant, although the leaf-margin and the size of the inflorescence agree better with the Mauritian plant. From the description it is clear that the plant must have come from Mauritius since plants from there always have a distinct reddish margin to the leaves, a character never recorded for the Reunion plant. There is now a considerable synonymy attributable to L. purpureum (Aloe purpurea) and most of the authorities attribute their plant to Rdunion, but in doing this they make the same mistake as Lamarck.

A New Species of Listera (Orchidaceae) from the Himalayas

While describing Listera mucronata Panigrahi & J. J. Wood from the Himalayas, China and Japan (cf. Kew Bull. 29(4): 731(1974)), we came across amongst the undetermined collections of Listera R.Br. in the Kew Herbarium, four plants (mounted on one sheet), collected by Kingdon Ward from the Himalayas on 23 August 1928 and bearing a note by V. S. Summerhayes that it may be a new species of Listera. A careful study of the specimens has convinced us that they represent a species with a lip very different from any in the genus Listera so far described.

Further Notes on Cistus palhinhae (Cistaceae)

Cistus palhinhae Ingram was the subject of a short article by B. E. Smythies in Kew Bull. 27(1): 154 (1972). The burden of the discussion was in reference to the number of valves in the fruit (or capsule) and whether this was adequate for differentiating between the 'gum' cistuses C. palhinhae and C. ladanifer L.; the former being described in Flora Europaea 2: 283-284 (1968) as having an ovary which is 6-locular while in the latter it is Io-locular. Smythies cites data he collected in April, 1971, in the vicinity of Cape St. Vincent and on the Sagres Peninsula, at the southern tip of Portugal, in which 208 capsules had valves varying in number from a minimum of 6 to a maximum of Io, 34 per cent. of the total being 8-locular and only 2 -4 per cent. 6-locular. Smythies compared these data with 439 fruits collected near Estepona in southern Spain, which had valves varying from 7 to 12, with 65 per cent. I o-locular. His discussion mentions the possible importance of the leaves of the two species, but contains no data relating to them.

Galearia (Pandaceae) Also in Thailand and Indo-China

In my recent account of Galearia Zoll. & Mor. (Kew Bull. 26: 153-165 (197I)), Thailand, Cambodia and Vietnam were unfortunately omitted from the notes on the distribution of G.fulva (Tul.) Miq., both in the key on p. 157 and under the heading 'Distribution' near the bottom of p. 163. Several collections by Kerr and others from these countries were in fact cited in the 'Index to Collections'. Moreover, G. dongnaiensis Pierre ex Gagnep., the type of which was collected in Vietnam, was cited in the synonymy of G. fulva on p. 162. References to Gagnep. in Lecomte, Fl. Gin. Indo-Chine 5: 457-8 (1926) were also included under G. fulva, following the synonyms G. affinis (R. Br.) Miq. and G. pedicellata (R. Br.) Miq. non Zoll. & Mor.

The Endocarps of Cocculus (Menispermaceae)

Summary. The surface-patterns on the endocarps of Cocculus are described and illustrated with SEM photographs. The value of these patterns in the taxonomy of the genus is discussed. Important taxonomic characters are provided by the form of the fruit and endocarp in the Menispermaceae. In some parts of the family, especially in the tribes Cocculeae and Tinosporeae, a remarkable variety of raised ornamentation on the surface of the endocarp is developed and the patterns formed by these projections are often quite distinctive for different genera and species. These patterns, however, are hidden within the fruit and in order to reveal the surface of the endocarp some simple preparation is necessary. It is no doubt partly for this reason and partly because of the difficulty of describing details of the ornamentation precisely in words that this character has not been used as much as it might have been. Information about these ornaments can clearly be better conveyed by illustrations. Miers in his monograph of the family (Contrib. Bot. 3 (1871)) paid some attention to endocarp characters, which were illustrated in many of the plates. The finer detail, however, is not clearly or always accurately depicted. Some further illustrations were provided in Diels's monograph in Engler, Pflanzenr. IV, 94(1910). Features of the endocarp were used in the descriptions and keys in my account of the Malesian species of Stephania in Kew Bull. I I: 41-69 (1956). The present account offers an illustrated review of the endocarps of Cocculus DC. as an example of the range of endocarp patterns occurring in one genus. Concurrently with this investigation a survey of leafepidermal characters of Cocculus was carried out by Dr. D. K. Ferguson, the results of which appear on pp. 485-488. Illustrations of the endocarps and leaf-epidermis of this genus will be of particular interest to palaeobotanists in view of the fossils of these parts which have been referred to Cocculus and to related genera. METHODS The fruits were first boiled in water for a few minutes to soften the pericarp, which could then be removed with a fine pair of forceps. As much as possible of the soft tissue adhering to the surface of the endocarp was picked off with the forceps. Then the endocarp was brushed clean with a stiff nylon brush of the type used in a dentist's drill; plenty of water should be used in this operation. (It should be noted that this brushing technique is only suitable for endocarps which do not bear delicate processes which can easily be broken off by the stiff bristles.) The endocarps were left to dry exposed to the air for an hour or so before being placed in paper envelopes. They were then left to dry further for at least several days in the dry atmosphere of the Kew Herbarium. In order to obtain photographs with a large enough depth of focus, a scanning electron-microscope was used. The relatively large size of the

Fadenia zygophylloides (Chenopodiaceae) New to Ethiopia

During the course of a study of the natural pastures of southern Ethiopia, undertaken jointly during late 1972 and early 1973 by G. Boudet, Head of the Service Agrostologique at the Institut d'Elevage et de Medecine Vetirinaire des Pays Tropicaux (ALF), and G. Rippstein, agrostologist, a collection of some 2400 numbers was made. Preliminary examination of these specimens revealed an unusual member of the Chenopodiaceae with winged fruits. I had the immediate feeling of having seen this curious plant before, and consultation of a recent part of the Kew Bulletin provided the solution: the plant was very recently described from Kenya as a new genus with the apt name of Fadenia zygophylloides Aellen & C. C. Townsend, Kew Bull. 27(3): 501 (1972) with a figure on p. 502. The new collection, cited below, was found approximately 8oo km east-north-east of the Kenyan type locality, the only other station known for this interesting genus.

Notes on the Pollen Morphology of Some Asiatic Bignoniaceae

Summary. The pollen morphology of 7 Asiatic species of the genera Radermachera, Heterophragma and the new genus Barnettia is compared and found to support the taxonomic separation of the genera. Three distinct pollen types are found in 6 Asiatic taxa of the genus Stereospermum and the genus Nyctocalos is shown to have two pollen types. The pollen morphology of the widely introduced Saritaea magnifica is demonstrated to be totally distinct from that of a random sample of 5 species of the genus Arrabidaea to which it has been assigned while the monotypic genus Macranthisiphon shows some similarities in pollen structure to that of Saritaea. This paper sets out to complement the taxonomic views of one of us (T.S.) contained in the preceding paper (Santisuk, 1973). It describes the pollen morphology of a small number of either native or introduced genera and species of the family Bignoniaceae, mainly from Thailand. During the course of preparing a revision of the Bignoniaceae for the Flora of Thailand, one of us (T.S.), was prompted to consider pollen morphology. It was thought that palynology could be a useful additional taxonomic character in this family, where generic circumscription is notoriously difficult. The publication of earlier workers, notably Urban (i916), Pichon (1946), Erdtman (1952), Sandwith (1968) and Mitra (1969) appeared to confirm its potential usefulness. Erdtman (1 952) has examined 25 species from 20 genera in the Bignoniaceae and these were found to show considerable variation. Airy Shaw (1966) cites the family as containing 120 genera and 650 species. This is a very large number in relation to the few taxa that have been studied palynologically and indicates that a fuller investigation of the pollen morphology of the family would provide additional characters which might resolve some of the taxonomic problems which exist at both generic and specific levels. The notes set out below, although referring to only a few genera and species, substantiate this view. Methods Pollen was obtained from specimens in the herbarium of the Royal Botanic Gardens, Kew (K). The specimens examined and the provenance of the material are listed below. Full details are not given of specimens already cited in the immediately preceding paper, for these see Santisuk in Kew Bull. 28: 171-185 (i973)Pollen for light microscopy was acetolysed by the method of Erdtman (I96o), but omitting the washing with glacial acetic acid after acetolysis, and mounted in glycerine jelly. Examination, measurements and micrographs were made using a Nikon L-Ke microscope. The measurements given are the means of measurements of approximately 15-20 pollen grains from each