Geniostoma rupestre var. glaberrimum (Benth.) B. J. Conn

Geniostoma hallei Sachet & Fosberg

Geniostoma hallei Sachet & Fosberg, Smithsonian Contr. Bot. 21:13, 1975.

Geniostoma rupestre sensu F. Brown, Flora, 227, 1935 [non J. R. & G. Forster, Char. Gen., 12, 1775; 24, 1776].

Shrub to 3 m tall, glabrous, nodes enlarged, internodes irregular in length, 4–20 (−25) mm long; leaves ovate to broadly elliptic, up to 7 × 3.5 (−4) cm, acute or rarely somewhat acuminate and mucronulate at apex, broadly acute at base, venation faint above, not prominent beneath, main veins (7–)8–9 (−10) on a side, not in regular pairs, bending slightly upward, becoming fainter and anastamosing near margin, network obscure, blade narrowed to a petiole 4–5 mm long, stipular collar truncate, 1.2–1.5 mm long very early rupturing down the interpetiolar sides; inflorescence a compound dichasium about 1–1.5 cm long, rather congested, twice trichotomous on a very short peduncle (very rarely, on the longest inflorescences, the central axis with an extra internode and the lateral dichasia each with a single extra outer pedicel from near base), a pair of ovate acuminate scale-like bracts at each ramification, the lowest connate, margins of bracts ciliolate, pedicels 2–4 (−5) mm long, with or without 1–3 scattered scale-like ovatetriangular ciliolate bracteoles; flowers white, foetid; calyx 2 mm long, lobed about ½ way, lobes triangular acuminate, ciliolate, slightly imbricate at base, corolla about 3 mm long, tube 2 mm, throat densely bearded, lobes suborbicular, imbricate in bud, obtuse, spreading at maturity, inner basal surface crinkly pilose, margins strongly ciliate, edges papillate without, stamens just over 1 mm long, anthers broadly ovate or triangular to broadly oblong, slightly longer than broad, about 0.8 × 0.6 mm, apex rounded, connective conspicuous, filaments very short, ovary broadly ovoid, stigma capitate, fleshy, sessile, constricted vertically and very slightly bilobed; fruit (immature) cylindric-fusiform, 8 × 3 mm, slightly beaked, beak tipped by shrunken stigma.

SPECIMENS SEEN.—Tahuata I.: “Région du sommet du Tahuata,” 17 Mar. 1973, F. Hallé 2170 (US, holotype, P, MPU, isotypes).

Very closely allied to G. astylum Gray of Tahiti, differing in the smaller less oblong leaves, much smaller, more contracted inflorescences, which are not or scarcely thyrsoid, in the more usual presence of bracteoles on the pedicels, in the somewhat acuminate much more ciliate calyx lobes, and in the corolla more densely bearded within.

Apparently very rare, one plant only seen by collector. A sterile specimen collected on Hivaoa, Feani, at 700 m, F. Brown 1096 (BISH), may be the same.

Geniostoma hallei Sachet & Fosberg

A G. astylum A. Gray foliorum venis alternis obscurioribusque, reticulo obscuriore, dichasio parviore non thyrsoideo, pedicello bracteolato calycis lobis acuminatis ciliatis, corolla intus valde barbata differt.

Shrub to 3 m tall, glabrous, nodes enlarged, internodes irregular in length, 4–20 (−25) mm long; leaves ovate to broadly elliptic, up to 7 × 3.5 (−4) cm, acute or rarely somewhat acuminate and mucronulate at apex, broadly acute at base, venation faint above, not prominent beneath, main veins (7−) 8–9 (−10) on a side, not in regular pairs, bending slightly upward, becoming fainter and anastomosing near margin, network obscure, blade narrowed to a petiole 4–5 mm long, stipular collar truncate, 1.2–1.5 mm long very early rupturing down the interpetiolar sides; inflorescence a compound dichasium about 1–1.5 cm long, rather congested, twice trichotomous on a very short peduncle (very rarely, on the longest inflorescences, the central axis with an extra internode and the lateral dichasia each with a single extra outer pedicel from near base), a pair of ovate acuminate scale-like bracts at each ramification, the lowest connate, margins of bracts ciliolate, pedicels 2–4 (−5) mm long, with or without 1–3 scattered scale-like ovate-triangular ciliolate bracteoles; flowers white, foetid; calyx 2 mm long, lobed about ½ way, lobes triangular acuminate, ciliolate, slightly imbricate at base, corolla about 3 mm long, tube 2 mm, throat densely bearded, lobes suborbicular, imbricate in bud, obtuse, spreading at maturity, inner basal surface crinkly pilose, margins strongly ciliate, edges papillate without, stamens just over 1 mm long, anthers broadly ovate or triangular to broadly oblong, slightly longer than broad, about 0.8 × 0.6 mm, apex rounded, connective conspicuous, filaments very short, ovary broadly ovoid, stigma capitate, fleshy, sessile, constricted vertically and very slightly bilobed; fruit (immature) cylindric-fusiform, 8 × 3 mm, slightly beaked, beak tipped by shrunken stigma.

Very closely allied to G. astylum A. Gray of Tahiti, differing in the smaller less oblong leaves, much smaller, more contracted inflorescences, which are not or scarcely thyrsoid, in the more usual presence of bracteoles on the pedicels, in the somewhat acuminate much more ciliate calyx lobes, and in the corolla more densely bearded within.

SPECIMENS SEEN.—Marquesas Islands: Tahuata I.: “Region du sommet de Tahuata, 17 Mars 1973,” F. Halle 2170 (US, holotype, P, MPU, isotypes).

Apparently very rare, one plant only seen by collector. A sterile specimen collected on Hivaoa, Feani, at 700 m, F. Brown 1096 (BISH) may probably be the same.

Geniostoma astylum Gray

Geniostoma astylum Gray, Proc. Am. Acad. 4:321. 1860b.—Seemann, Fl. Vit. 164. 1866.—Drake del Castillo, Ill. Fl. Ins. Pac. 7:236. 1892; Fl. Polyn. Franc. 126. 1892.

DESCRIPTION (after Gray).—Leaves ovate. Stipules truncate, bifid. Sepals ovate. Aestivation quincuncial. Corolla glabrous within. Stigma sub-globose, sessile, entire. Immature fruit narrowly oblong.

RANGE.—Society Islands: Tahiti: U. S. Exploring Expedition in 1839 (fide Gray). Not seen.

Geniostoma quadrangulare Fosberg

Arbor parva, glabra, ramulis quadrangularibus nodosis, internodis 5–20 mm longis; foliis ellipticis tenuibus petiolatis; dichasiis compositis sub-thyrsoideis internodis 3–4; fructibus ovoideis 5–6 mm longis, valvis sclerosis.

Tree to 5 m tall, glabrous, branchlets notably quadrangular, nodes prominent, internodes 5–20 (−30) mm long, leaves thin, blades to 7.5 (−9) × 2–3.5 (−4.5) cm, elliptic, rarely ovate or oblong, apex obtusish, slightly acuminate, base cuneate, decurrent to a slender petiole 5–9 (−10) mm long, veins about 4–5 pairs, subopposite, strongly ascending, forking and anastomosing near margin, network rather obscure; stipular collar with lobes very low, broadly rounded; inflorescences, in bud axillary among leaves, in flower among lower leaves and on several nodes below lowest leaves, in fruit persisting on 3–5 nodes, 4–7 internodes below leaves, compound decussate dichasia thyrsoid to the extent that the main axis has 3 or 4 nodes and internodes below the terminal dichasium, the lateral branches strongly ascending, lower ones on well-developed inflorescences each with an extra outer branch arising just above the base, each ramification subtended by a pair of broadly ovate scale-like bracts enclosing the base of the lateral branch, pedicels 3–5 mm long, with a tiny triangular scale-like minutely ciliolate bractlet slightly below the receptacle; calyx lobed about half-way into 5 triangular bluntly mucronate papillate-ciliolate lobes about 0.7–0.8 mm long; corolla with tube about as long as calyx, lobes about as long again, ovate, with 3 slightly branching veins, margins papillate-ciliolate, inner surface distally minutely puberulent, basally prominently bearded; anthers broadly oblong, about 0.7 mm long, rounded at apex, with short rounded lobes at base, sessile in sinuses of corolla; stigma capitate, on a very short style, included in corolla, exserted from calyx after corolla has fallen.

SPECIMENS SEEN.—Austral Islands: Rapa: Mt. Tepiahu, 150 m, Fosberg 11502 (NY, BISH); southeast ridge of Mt. Pukunia, 350 m, Fosberg 11431 (BISH); Pake, 100 m, A. M. Stokes 384 (BISH, type); Titivake, east side of Mt. Vaitau, St. John & Maireau 15392 (US, BISH); Area, 140 m, St. John & Fosberg 15332 (BISH, US).

4. Ipomoea tiliacea (Willdenow) Choisy in the Pacific

Ipomoea tiliacea (Willdenow) Choisy in de Candolle, Prodr. 9:375, 1845.—Yuncker, Bishop Mus. Bull. 220:227. 1959.

Convolvulus tiliaceus Willdenow, Enum. Pl. 203, 1809.

Convolvulus fastigiatus Roxburgh, Hort. Beng. 13, 1814.

Ipomoea fastigiata (Roxburgh) Sweet, Hort. Brit. 288, 1826.

Two Pacific Island morning-glories, one of them mistakenly placed in the genus Merremia, are described as varieties of the tropical American Ipomoea tiliacea. They may represent an extension of the natural distribution of this species, or they may be old, well established introductions by human agency.

This species has previously been known from the Pacific only from Fiji and Tonga, where it was formerly usually called Ipomoea fastigiata (Roxburgh) Sweet. Otherwise it is tropical American. The Marquesan collections, reported here, and the Fijian-Tongan ones, seem to represent distinctive populations, with a few characters uncommon or absent in the variable, widespread American species.

Geniostoma astylum A. Gray

Geniostoma astylum A. Gray, Proc. Amer. Acad. 4:321, 1860.

This Tahitian species has apparently hitherto only been known from the original collection, U. S. Exploring Expedition (US), and was only very briefly described by Gray. The type-specimen is excellent except for lack of flowers and of mature fruit. It is probable that a flowering specimen once existed in the Gray Herbarium, as there is a set of drawings of the flower there, presumably drawn by Gray from the original material. A copy of these has been furnished us by Dr. William T. Gillis, but he was unable to locate the specimen (in litt., 1974).

Duplicates of two old collections, kindly sent by the authorities at the Paris Herbarium, identified by Nadeaud as G. rupestre Forster f., and cited as such by Drake del Castillo (1892:126), appear to belong to this species. They, with one other, Lépine 208, which we have not seen, form the basis for the reports of G. rupestre from Tahiti. In all probability the latter species does not occur at all in Tahiti, and probably not in southeastern Polynesia.

The following somewhat amplified description, based on the type and the two specimens mentioned, all cited below, is offered to make possible a better understanding of the relationship between this species and the new Marquesan one described below.

Branchlets smooth, terete, 2–3 mm diameter, not conspicuously nodose, internodes 1–4 cm long, leaves oblong to oblong-elliptic, up to 11 × 5 cm, veins inconspicuous, (7−) 8–11 on a side, nearly opposite, network quite visible on upper surface, apex bluntly slightly acuminate, base acutish to rounded, petiole 2–8 mm long; stipular collar early splitting down the sides in the type, but not notably so in other material; inflorescences loosely thyrsoid, to 3 cm long, main axis with 3 or 4 nodes, each ramification with 2 scale-like bracts, these ovate, recurved, acute, mucronulate, basally enclosing the inflorescence branch, ultimate ramifications tending to be irregular, each lower and middle branch trichotomous or at least with a pair of bracts part way up, rarely with a single additional outer dichasium near base, pedicels 1–3.5 mm, puberulent, center ones tending to be short, uppermost branchlets (pedicels?) rarely bearing a pair of reduced ciliolate bractlets under the calyx or a single such bractlet part way down; calyx 1–1.5 mm long, lobed about half-way, lobes ovate-triangular, obtusish to acute, tending to be folded and to appear acuminate, margins papillate-ciliolate; corolla glabrous, or somewhat pilosulous within throat, tube shorter than lobes, lobes imbricate, ovate, obtuse to rounded, faintly 5-nerved, about 1.5 mm long and wide; anthers very broadly oblong-sagittate, rounded at apex but with a very short blunt mucro, on short filaments; ovary broadly ovoid, style almost none, stigma ovoid, slightly bilobed; fruit 8 × 2.5–4 mm, fusiform to oblong, slightly compressed, furrowed along septum, slightly beaked, valves hard, recurved and widely spreading after dehiscence; seeds oval, somewhat irregularly compressed but not at all angulate, about 1 mm long, surface areolate reticulate, embedded in dried remains of soft fleshy placenta, this almost completely shrunken away at dehiscence, the network, or boundaries of the areolae, very minutely crinkly or very closely undulate, the bottoms of the areolae slightly convex.

This species has hitherto been principally characterized by the absence of a style, with little attention paid to other characters. This lack of a style is not altogether unambiguous, as the ovary is gradually narrowed to a point which bears the capitate slightly bilobed fleshy, persistent stigma. As long as the fruit is not fully mature it is gradually narrowed and even at maturity there is an abrupt short beak, which could be interpreted as a very short persistent style. That it has been so interpreted is shown by the placing, by Nadeaud and Drake del Castillo, of the two additional collections cited below in G. rupestre rather than in G. astylum, where they belong.

The so-called bifid stipules likewise do not effectively separate this species from its congeners, as this is only a rupturing of the stipular collar, which is not evident in the other collections and may be merely a function of vigorous enlargement of the young branchlets on the type-collection.

Although the reduction of the style is a useful character for recognition of this species and its closest relative, described below, a more fundamental feature of G. astylum is the thyrsoid inflorescence. Thyrsoid is here used in the sense of having the central axis with more than 2 nodes versus the usual condition in the genus of a dichasium or a compound dichasium. This feature, as well as others noted below, distinguish it from the Marquesan species described below, which on other grounds seems to be its closest ally.

SPECIMENS SEEN.—Tahiti: s.l. U. S. Exploring Expedition (US, type); Nadeaud 363 (US, 2 sheets, one flowering, the other with mature fruits, probably not of the same gathering, the number merely that used by Nadeaud in his Enumeration); Vesco in 1847 (US) (inflorescence somewhat more complex than those of the other collections).

Geniostoma quadrangulare is a species of plant in the Loganiaceae family. It is endemic to French Polynesia.