side of the midrib; 18 to 23 cm. long and 7.5 to 12.5 cm. broad. Calyx short tomentose externally, becoming glabrous with age; densely silky-villose inside; its tube including the ovary about 2.5 to 2.8 cm. long, often split on one side; ribs conspicuous, ending beyond the truncate margin into 5 linear teeth, 16 mm. long. Corolla with a tube of 21 to 22 em., the lobes about 4cm. by 4 cm.; the villosity as in the form typica.

"Variety glabra De Wildeman (1907, p. 163).

"Petiole 15 to 30 mm. long, glabrous. Leaf-blade long cuneate at the base, glabrous on both faces, shiny above, dull below; with about 14 lateral veins on each side of the midrib; 18 to 26 cm. long and 6 to 10.5 cm. broad. Calyx glabrous externally; the tube including the ovary about 2 cm. long (in the bud), the teeth 6 to 15 mm. long" (De Wildeman, 1907).

Belgian Congo: Kasai: Bombaie (E. and M. Laurent). Middle and Upper Congo: Eala, type locality (Pynaert; M.Laurent; variety typica); Coquilhatville (M. Laurent; variety subglabra). Eastern Congo Forest: Yambuya (M. Laurent; Solheid; variety subglabra and variety glabra); Avakubi (January 13, 1914; J. Bequaert; Coll. No. 1917).

De Wildeman's figure of a flowering live plant (1907, p. 160, fig. 5) shows that the very large, solitary, terminal flowers are pendent. According to the same author, it belongs to the group of R. malleifera (Hooker), which species, however, differs in the absence of ant-swellings, the smaller corolla with much denser and longer tomentum on the tube, and the villosity of the stem.

Randia physophylla K. Schumann Randia physophylla K. Schumann, 1899, Engler's Bot. Jahrb., XXVIII, pt. 1, p. 64. E. De Wildeman, 1903, 'Etudes Flore Bas- et Moyen-Congo,' I, p. 81; 1907, ibid., II, pp. 74 and 164; 1912, ibid., Ill, pt. 3, p. 487. Th. And H. Durand, 1909, 'Sylloge Flor. Congol.,' p. 260.

"Leaves very short petiolate or subsessile, oblong, short and sharply acuminate, broadly cuneate at the base, subcordate and auriculate below, the earlets excavated and glandular; leaves very glabrous on both sides, resinous and very shiny. Ovary, to judge from the fruit, globose, glabrous and scabrous. Calyx tubular and irregularly 5-lobed, the lobes costate and scabrous. Corolla pentamerous, each of the 5 lobes divided in the upper part into obovate, obtuse, carnose laciniae. Anthers curved, broad. Style exserted for a long distance out of the corollar tube; subelavate and sulcate in its upper part. Berry globose, crowned by the calyx.

"The petiole is hardly 3 to 4 mm. long. The blade has a length of 30 to 35 cm. and a width in the middle of 12 to 14 cm.; it is crossed on each side of the midrib by 23 to 25 heavy lateral veins, which are visible on both upper and under surfaces; the leaf is shiny chestnut-brown in dried condition. The two semiglobose glandular cups at the base of the leaf are 5 mm. deep. The glands of the stipules must secrete an abundance of resin, for it fairly drenches the leaves and forms a crust at the base of the petiole. The calyx has a length of 3 to 3.5 cm. The corolla is very fleshy, 18 to 19 cm. long, of which 15 cm. is the lergth of the tube. The stamens are 1.3 cm. long. The style exceeds the corollar tube by about 3 cm. The berry has a diameter of 2.5 cm." (K. Schumann, 1899).

Cameroon: Grand Batanga (Dinklage); Bipindi (Zenker).

Belgian Congo: Lower Congo: Kisantu; Lukaya (Gillet); Sanda (Oddon); Kwango Region (Butaye); Leopoldville (April 15, 1915; J. Bequaert; Coll. No. 7347). Middle and Upper Congo: Ikela (Jespersen); Eala (M. Laurent); Lubi (Lescrauwaet).

Ecology Of Randia Lujx The species was discovered by Luja in 1903 along the Sankuru River in the Belgian Congo. According to De Wildeman (1904a, pp. 282-284; 19046) its myrmecodomatia are very similar to those of R. myrmecophyla described in detail below. They consist of spindle-shaped swellings of the internodes, about 2 to 3 cm. thick and hollow; one or two apertures, in the widest part of the swelling, lead into the cavity. There are, in addition, on the leaves, in the axils of the nerves acarodomatia in the form of small pouches. The ants found by De Wildeman in the domatia of Randia Lujse have not been identified.

Ecology Of Randia myrmecophyla

On only one occasion did I observe this species in the field. At Avakubi, in January, 1914, a specimen was found in the primitive Rain Forest, in a rather dry place. It grew as a bush with very broad and long, glabrous, smooth leaves; the blades were as much as 30 cm. long and 15 cm. wide and borne on a petiole sometimes 4 cm. long. The large, white, pendent flowers were very striking. The plant agreed perfectly in all particulars with De Wildeman's descriptions, photographs, and drawings of R. myrmecophyla.

The myrmecodomatia of this Randia (Fig. 93) are quite peculiar, being elongate, regular, spindle-shaped swellings on the middle portion of the internode, and extending about half its length. These expansions seem to occur in all the internodes of the various branches, usually present one circular aperture, occasionally two or three, near the middle of one side, and are inhabited by ants. A longitudinal section shows the interior of the enlarged part of the internode to consist of a spacious cavity, 10 to 12 cm. long and 6 to 7 mm. wide, which stops a long distance from the nodes.

The ants I found in the myrmecodomatia of the specimens at Avakubi belonged to a small species of Crematogaster recently identified by Santschi as C. rugosa (Andre). Each cavity apparently contained its own formicary with brood, and in many instances was divided into a series of chambers by transverse walls of brown, malaxated pith debris. Sometimes one hollow would thus be separated into four successive compartments communicating by one or two holes pierced through the

Fig. 93. Bandia myrmecophyla De Wildeman: a, portion of branch showing swollen internode inhabited by ants; b, longitudinal section of this internode; c, entrance to cavity; p, partitions built by ants. Drawn from life at Avakubi, January, 1914; one-half natural size.

partitions; even then, there would usually be only one external aperture to the domatium. By means of these dividing walls the ants undoubtedly make a much more efficient use of the hollow internodes, for it has been observed that in such cases the larvae and pupae are kept toward the nodes in the narrower upper and lower stories. Coccids are also common companions of the ants in this Randia.

Crematogaster rugosa is a small and timid ant and probably does not give its host much protection. Even when the branches containing formicaries are shaken, the inmates do not leave their retreats. The specimen near Avakubi, though settled by ants, had its leaves badly eaten by phytophagous insects.

Em. Laurent, the discoverer of this Randia, recognized its myrmecophily in the field. He found an unidentified ant and coccids in the swollen internodes. I am not aware that additional information on this plant has been published since, but Kohl in later years has collected from its domatia specimens of Camponotus foraminosus Forel and Cataulacus weissi Santschi (Forel, 1916, pp. 427 and 443).

Ecology Op Randia physophylla I found a specimen of this species in a forest gallery near Leopoldville, in April, 1915. It was a small tree, with very large leaves, about 46 cm. long and 27 cm. wide, on short petioles (1 cm.). The young leaves, before complete expansion, are viscose, being covered with a resinous, sticky substance. The large, showy flowers are erect; their calyx ends in broad lobes; the corolla, about 26 cm. long, is dirty white in its upper part and greenish white in the tubular, lower portion. The egg-shaped fruit is 6 cm. long without the persistent calyx, 4 cm. thick, and deprived of ribs.

This species has no swellings on its branches and the stem is never hollow nor inhabited by ants. At the base of the leaf-blade (Fig. 94), on both sides of the midrib, there is an evagination of variable size, convex on the upper surface of the leaf, broadly open below. On some blades it consists of a mere inflation of the leaf-base, whereas in others it may be 4 to 6 mm. deep and pouch-like, 5 to 8 mm. long and 6 to 7 mm. broad. In all cases, however, on looking into it from the under side, one finds in the bottom, close to the midrib, a conspicuous pale brown gland which secretes a sweet substance. On some of the leaves of the specimen I examined near Leopoldville, a number of ants, Crematogaster africana subspecies laurenti variety zeta (Forel), had taken possession of these distended nectaria, closing the opening on the under side with a tent of fine, agglutinated, dark brown vegetable fibres. Frequently they were accompanied by coccids. Never having seen queens or brood of the ants in the leaf swellings, I can not regard these structures as forming part of the nest. Ants of the same variety occasionally build fibrous shelters over coccids which are fixed on the fruits of this Randia.

From the foregoing it is evident that Randia physophylla is not a true myrmecophyte in the sense generally meant by this term. Yet its relations with ants are not without interest, for here we have a primitive stage leading to the production of true ant-pouches such as those of Scaphopetalum Thonneri, Cola Laurentii, and certain South American Melastomacese.

Fig. 94. Randia physophylla K. Schumann: a, base of leaf-blade with the two swellings, seen from above, natural size; cross section of this base, one and one-half natural size; the nectarium is placed in n. Drawn from life at Leopoldville, April, 1915.

Plectronia Linn.eus, 1767, 'Mantissa Plant.,' I, p. 52. K. Schumann, in Engler and

Prantl, 1891, 'Die Natiirl. Pflanzenfam..' IV, pt. 4. p. 91. Canthium Lamarck, 1783, 'Enoyclop. M6thod.,' I, p. 602. Hiern, 1877, in Oliver,

'Flora of Tropical Africa,' III, p. 132.

Shrubs or trees, often climbing or clambering bushes, occasionally spinous, with opposite leaves and branches, and acuminate stipules from a broad, often sheathlike base. Frequently some of the branches are sarmentose, hooked or winding; or the plant emits whip-like shoots, often many meters long, somewhat compressed, leafless or with small leaves, furnished with heavy, more or less recurved spines; these shcots trail along the ground or work their way up the trees. Flowers small, axillary, in dense cymes or umbels, or short panicles or clusters. Calyx-tube short, turbinate, campanulate, or hemispherical; limb short, 4- or 5-toothed or cleft, or subtruncate, deciduous. Corolla coriaceous: tube rather short, exceeding the calyx, glabrous outside, hairy with a ring of deflexed pilose hairs or rarely glabrous inside; throat rather constricted or dilated, often bearded; lobes 4 or 5, rarely 6, ovate or lanceolate, reflexed, usual!}, glabrous, valvate in the bud (toward the apex sometimes induplicatevalvate). Stamens 4 or 5, rarely 6, exserted, inserted at the mouth of the corolla; filaments short; anthers ovate, or oval, or lanceolate, acute or obtuse, usually subsagittate at the base, as a rule glabrous, fixed at the back. Ovary 2-celled, fleshy. Style flexuous, filiform or thickened, exserted or equalling the corolla, usually glabrous. Stigma capitate, calyptriform or mitre-shaped, sometimes bifid at the tip, often sulcate. Ovules solitary, pendulous, orthotropous, the micropyle directed upward. Fruit a drupe, didymous, subdimidiate, or globose, 2-celled or by abortion 1-celled; stones 2 or 1, sometimes subrugose. Seeds pendulous, solitary, nearly straight or curved, sometimes bent into the form of a horseshoe round the placenta; testa membranous; albumen fleshy, sometimes ruminated; embryo cylindrical, nearly straight or curved, axile; cotyledons short, radicle surerior.

Plectronia Linnanis