The Journal of Indian Botany/Volume 1/January 1920/Miliusa and Saccopetalum
MILIUSA AND SACCOPETALUM.
(Family Anonaceae)
By
J. R. Drummond, F.L.S.
The genus Miliusa was founded by Alphonse De Candolle (in Mem. de la Soc. de Phys. et d'Hist. nat. de Geneve vol. V., 1832) on a plant collected by Leschenault de la Tour "in niontibus Cotta-lam dictis acl peninsulse indicse meridiem". Cotta-lam has been identified with Courtallam in the Tinnevelly District of the Madras Presidency (S. India).
The generic character, rendered into English, is as follows:—
Corolla gamopetalous, campanulate, three-lobed. Stamens 12? with slender elongate filaments, and very small anthers. Eeceptacle ovoid. Ovaries indefinite, 2-ovuled, the ovules superposed. Carpels free.
From the detailed description we gather further that the Miliusa was a low shrub with bifarious elliptic leaves, and solitary axillary flowers, consisting of a triad gamopetalous corolla (or three petals, about nine lines long, connate for half their length) concave or hooded at the base concealing the pedicel and the small calyx of three sepals, the petals folded internally so as to form three hairy fimbriate appendages, one opposite each of the main lobes of the corolla. The anthers, scarcely 1/20 line long, are inserted on the receptacle, supported by slender glabrous filaments, and rounded. The receptacle is very hairy. De Candolle observes "Genus ex habitu, corolla gamopetala, basi concava, et interne reduplicata, distinctissimum."
Plate No. iii accompanying the Memoir represents "Miliusa Leschenaultii, Alph. DC." which is manifestly the Miliusa indica of the text, although at the right hand upper corner a portion of a leaf (figure 8) is included which is not accounted for in the letter press, and may belong to some other plant.
From this illustration it appears that the torus in Miliusa indica consists of two portions, of which the lower, constituting about one-fifth of the whole, is glabrous, the remaining four-fifths being pilose; the stamens are inserted at the division between these two portions and the corolla, at the base of the lower (glabrous) fifth one corolline whorl is visible, the lobes of which are connate for about two-thirds of their length, and prolonged, "hooded"—or rather saccate—, at their bases, completely hiding the small sharply refracted "calyx", of which the segments are rather strongly ciliato; the appendages of the corolla appear as tufts of hairs inserted at the base of the torus, remaining after the petals have been taken away. It should be here noted that the whorl which the author described as a calyx may have been in fact an outer series of petals, conforming, as in certain allied species, to the true sepals, which in this case, however, must have been highly caducous.
In 1834 Wight and Arnofct (Prodromus p. 10) under "Miliusa indica (Lesch.)" reproduced A. Le Candolle's leading characters, but assigned them to " Wall. L.n. 5433, " quoting as a synonym Uvaria ciliata, Heyne MSS." There is a specimen at Kew ticketed Uvaria ciliata, Heyne Tenmalej near Courtallam, July 1815," and on the same sheet is a second ticket from which it seems probable that the citation of " Wall. L.n. 5433 " may refer to this specimen or to a duplicate.
In April 1835, Wight got a plant at Courtallam which he ultimately referred to Miliusa indica, and in the following July and August he collected further specimens which together with the April gathering have since (1866-67) been distributed from Kew as No. 34 of the Indian Peninsular Collections. These later gatherings (in part) resemble "Uvaria ciliata, Heyne" so far as can be judged, but Heyne's specimen is not in fruit : No. 34 of Wight has drupes and matches an example from his own Herbarium, without date or original locality, with which is now attached a description in his own band-writing. This description, however, seems to have belonged to thspecimen distributed under No. 33 as "Miliusa montana, Gardner" (which in PL Brit. Ind. i. 86 is reduced to M. indica) and to have been pinned to the sheet where it is now found by accident. A pencil note on the sheet from Wight's own Herbarium (in Sir J. D. Hooker's handwriting apparently) points out that the plant there represented differs from No. 33 by the ripe carpels being sessile and pubescent-tomentose. This form (No. 34 in part) seems to have received from Wight the manuscript name of "M. affinis". Nothing on these sheets can be referred to Alph. De Candolle's M. indica unless we assume—
(1) that the sepals, which in Nos. 33 and 34 Herb. Pen. Ind. are manifest, may sometimes fall off at a very early stage, or
(2) that the sexes are diclinous and that the structure of the androecium differs in the male and female flowers very widely, or
(3) that the arrangements of the floral whorls is remarkably unstable.
How far any parallel to the degree of instability that must be supposed in this case has been observed in other Anonaceae is a question which may be deferred for the present. In the "Illustrations" i, p. 68 (1840), Wight met this difficulty by suggesting that Da, Candolle was misled by imperfect material, and this theory was adopted and elaborated in the same year by J. J. Bennett, when dealing with a tree found by Horsfield in the "Banyumar Province" of Java, on which Bennett's genus Saccopetalum was founded (Plaht, Jav. Ear. p. 165 t. f xxxv : 1840).
Bennett remarked that since the publication of the family in De Candolle's Prodromus two new genera of Anonacere had been constituted, viz., Milium and Hyalostema. With "Hyalostemma we need not concern ourselves further than to say that it was coined by Wallich without any diagnosis, for a plant which had been duly described by Eoxburgh (Fl. Ind. ii. 660) as Uvaria dioeca. Bennett's note adds nothing to the history of " Hyalostemma " (which has subsequently been dropped by common consent), and his discussion of De Candolle's plant does not advance the history of Miliusa, because he postulates the identity of Wight's species with "Miliusa Leschenaultii", which, as we have seen, can only be accepted by making alternative assumptions, in support of which no proof has been put forward.
As it happens, a good deal of the reasoning expended on the matter is invalidated by facts since discovered. Speaking of that group of Anonaceae, of which Miliusa has been taken as the type, Bennett writes:—
"The stamina also are subject to some modifications, less extensive however than the character and description of Miliusa given by M. Alph. De Candolle would lead us to believe. Their number in that genus, according to my observation, is about 27 instead of 12, forming three alternating series, in each of which two are opposed to each of the inner, and one to each of the outer petals ". Now, in Miliusa nilagirica Beddome, Ic. PI. Ind. Or. t. lxxxviii (1876) there are but eight stamens : that this is a Miliusa no one probably will dispute, and in that case Bennett's estimate of the stamens as " about 27 " obviously calls for revision. It seems even possible that this plant, and not either of Wight's Miliusae, was the true M. Leschenaultii* The glabrate middle surface and margin thickened towards the apex of the petals, which are given as distinctive of M. nilagirica are approached in some examples of ill. montana, Gardner, and these differences are not sufficient, perhaps, to mark off Beddome's species from that of De Candolle. Beddome's illustration Ixxxv serves to contrast M. a finis, Wight MSS., — which is there figured as " M. indica", — from M. Leschenaultii. The number of the stamens in the last differs, as observed, from that M. nilagirica, but it may be questioned whether the number is so fixed in this group as was supposed by Bennett. As regards the structure of the valvate petals he has very justly noted that the gamopetaly of the inner row is less real than apparent, being due to a partial cohesion of their edges, which in certain other Anonaceae takes place, so to speak, in an inverted order, the cohesion being at the tipes, so as to form a canopy over the androgynaecium, somewhat as in Vitis.
More disputable matter is involved in his next argument, as follows:—
"Now the three supposed divisions of the calyx in M. De Candolle's figure alternate with the three cohering divisions of the corolla and consequently represent the outer petals, the calyx being thus altogether omitted. In the description this deficiency seems to be supplied by the three supposed internal appendages opposite the base of the cohering petals, of which, however no traces are observable in the figure . . . .", and he adds, "This supposition" (i.e. that the outer row of petals was taken for a calyx) "may at least serve to explain the description; it is less easy to account for the figure, but it may be presumed that the artist, aware that the plant was described as having only three division to its calyx, was satisfied with " having found that number of sepaline parts, and it is possible that the true sepals (easily detached at maturity as in Saccopetalum and Hyalostemma) may have fallen off during the process of manipulation ".
It is obviously just as likely that the "sepals" were naturally caduous; but the case of the fimbriate processes rests on a distinct footing, because, although somewhat disguised in the drawing by a dotted line (b), which indicates the point of insertion of the corolla, they are quite clearly shewn in the figure. These organs are perhaps correlated with the special structure of the androgynaecium, and the saccate, probably nectariferous, development of the " petals ". Traces of like tufts seem to the writer to be present in other species of Miliusa as well, and it may be that the degree of their development is variable even in the same species, as is seen to be the case with the so-called petal-claw or gland in certain species of Greioia from the same parts of S. India.
Further material and particularly observations in the field may necessitate emendation, but in the meantime local botanists will presumably keep up Miliusa Leschenaultii (type of the genus), M. affinis, M. Montana, and M. nilagirica as distinct, though closely allied species. If facts should be adduced in the future to shew that M. Leschenaultii and M. nilagirica, or M. affinis and M. montana should be looked upon as a single unit, it is comparatively easy to carry out the necessary technical corrections.
To return to the history of the genus, — Bennett, having as he believed disposed of Miliusa Leschenaultii, went on to establish his new genus Saccopetalum; but as is shewn in the Genera Plantarum (Vol. I, p. 28), the only distinction between Saccopetalum and Miliusa lies in the saccate petals of the former, whereas A. De Candolle in his description no less plainly than in the accompanying figure has given this very character as belonging to the only species of Miliusa known up to the time when Bennett wrote, because what is now Miliusa Roxburghiana, Hook. fil. & Thorn, was excluded and referred to the factitious Hyalostemma. In the Flora Indica, Vol. I, p. 92, the generic character was amended by restricting Miliusa to those species that have not more than two ovules, but as further species were examined this distinction seems to have been found untenable, though retained in a modified form in the Flora of British India, due warning being at the same time conveyed that Saccopetalum had been reduced to Miliusa by Baillon (Hist, des Planfces I 244).
Hook. fil. & Thorn, at the same time pointed out that Saccopetalum tomentosum is intermediate between Saccopetalum and Miliusa, i.e. presumably between Miliusa, affinis of Wight MSS. and the Javan Saccopetalum Horsfieldii of Bennett. Baillon (I.e.) and Prantl. (Nat. Pilanzenfam. Ill 2.29) do not even admit Saccopetalum to the rank of a subgenus. Comparing the number of the ovules in the different genera included in the "Genera Plantarum" under Miliusete we hardly find sufficient ground for maintaining Saccopetalum as an independent genus ; in Orophea, it is true, it is said that there are never more than four ovules, and in Alphonsea always more than four, with eight as a maximum; but in Bocagea, which is admittedly closely allied to Miliusa, they are given as 1—8. In the critical note now attached to a sheet from his own Herbarium, written up at Kew (by Sir J. D. Hooker probably) as ' Miliusa affinis, E. VvV, mentioned above—Wight has observed "On examining the ovaries of Miliusa somewhat advanced, I find them containing 2-3 and, once or twice, 4 ovules superposed; also probably there are two or three species distinguished by the stamens being few or numerous and the carpels glabrous or hairy". Whether therefore we assume that the number of maturing ovules differs in the species, or that it varies with the individual, little weight can be attached to this character in discriminating Miliusa from its allies. It appears, moreover, that in Saccopetalum the number or the ovules is not always six or more ; in the ' Flore Forestiere de la Cochinchine ' at plate 38 (1881) Pierre has figured and described as Miliusa Bailloni a tree so closely allied to Saccopetalum Horsfieldii, that the two could not properly be referred to different genera, but in this plant it is expressly noted that the ovules are not more than four in number.
In attempting to frame an amended definition of the genus Miliusa two special difficulties are encountered ; the one is due to the obscurities, above stated, which surround De Candolle's type; the other is presented by the genus Phcsanth'is of Hook. fil. and Thomson (Flora Indica p. 146). Phasanthus cannot be discriminated from Miliusa, whether Saccopetalum be merged in Miliusa, or accepted, save by the structure of the staminary whorl; but Baillon (Adansonia viii 1868, pp. 312 et seq.)—has given reasons for thinking that this character does not in fact possess the value formerly assigned to it, and Phceanthus is so nearly akin to the type of Saccopetalum in habit, in the structure of the outer floral whorls, and of the ovary, that this genus also should perhaps be reduced to Miliusa.
The arrangement of the highly natural but difficult family of the Anonaceae might possibly be simplified, if, instead of attempting to distinguish between 'sepals', and 'petals', the floral envelope were treated, for taxonomic purposes, as a single perianth, consisting of subsidiary, sometimes sharply differentiated, whorls.
In the subjoined description, for the sake of convenience, the accepted characterization of the perianth whorls has been followed the species placed under Plueanthus of Hooker and Thomson have, for the same reason, been excluded.
MILIUSA
Genus Anonacearum imprimis ex-indicatione Leschenaultuab Alph, Candolles in Mem. Soc. Phys. et Hist. Nat. Genev. vol. V (1832) p. 37, t. iii supra speciem unicam Indicam constitutum, nunc propter plures species nuper recognitas iterum ut sequitur breviter descriptum.
Flores hermaphroditi vel unisexuales, in cymis, vel fasciculis dispositi, aut in axillis solitarii. Sepala tria, inconspicua, basi vis connata. Petala, aestivatione valvata, per duo verticillos valde dissimilos disposita, exteriora parva sepaloidea, nonnunquam refracta, interiora majora, vix androecium celantia, membranacea vel hyalina, nee unguiculata, nee ad apicem producta, versus basin concava vel saccata, rarius explanata, margin ibus plus minus colnurentibus, raris-sime discretis.
Torus productus subglobosus vel cylindricus, spice aliquando truncato. Stamina 8-12, aut ad 36 in gradibus disposita, ver indefinita antheroc subdidyinaj, loculis contiguis ovatis vei rotundatis, extrorsae, saepius minutaT; filamenta manifesta, attenuata, vel connectivo incrassato, plus minus apiculato, vix superne dilitato. Carpella numero indefinita stipitata, matura forma oblonga, ellipsoidea, vel globosa, parum succulenta, indehiseentia, in pseudocarpum nunquam coalita:—ovula in venterali sutura (an semper?) affixa« saepissims bina (rarius unico per abortuin superstite), vel indefinita:— stylus abbreviatus, stigmate simplice oblongo. Semina 1-6 (vel plura?), lateraliter compressa vel in sectione transversa cuneiformia.
Arbores, arbuscula, vel frutices humiliores, per regiones Asiae australes, et Indo-Sinenses, usque ad Australian subtropicam dispersae. Species circa 21.
It is usual to ascribe the foundation of Miliusa to the discoverer of the type species, but it does not appear that he laid claim to anything beyond the dedication, and the descriptions throughout are evidently the work of De Candolle. The present description is necessarily tentative and is put forward partly as a contribution towards a much needed revision of the family, or at least of that group to which Miliusa naturally belongs. Much better material, in the fruiting stages particularly, must have accumulated since the account in Genera Plantar um was published.
The writer will be grateful for any specimens of Miliusa, Saccopetaluir, or Phfeanthus that can be spared on loan or otherwise for study at Kew in order to complete a key to the species which it is proposed to include under Miliusa.