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(Last Modified On 12/18/2012)
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(Last Modified On 12/18/2012)
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Genus
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GUSTAVIA L.
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PlaceOfPublication
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P1. Surinam. 18. 1775, nom. conserv.
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Synonym
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Japarandiba Adans. Fam. 2:448. 1763, nom. rejic. Pirigara Aubl. Hist. P1. Guian. 1:487. 1775, pro parte. Teichmeyeria Scop. Introd. 267. 1777. Spallanzania Neck. Elem. 2:79. 1790.
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Description
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Trees, frequently of gigantic size, rarely shrubby, the leafy twigs ordinarily stout. Leaves usually crowded toward the tips of the twigs, petiolate to sessile, usually conspicuously serrate and large, occasionally rather small for the family and entire or subentire. Flowers usually lateral and cauliflorous, occasionally terminal or subterminal. Hypanthium broadly urceolate, smooth or indefinitely, rarely conspicuously, winged or ribbed. Calyx manifest or reduced to a more or less obscurely 4- to 6-lobed ring. Petals 6-12, rather unequal, large and showy. Androphore radially symmetrical, wholly fertile, the elongate inflexed fleshy fila- ments of the innumerable stamens coherent at the base into a shallow perigynous ring adnate to the base of the corolla; anthers narrowly cylindrical, dehiscent by 2 apical pores. Ovary 4- to 8-celled, containing numerous lateral anatropous ovules on a stout axile placenta; style conic, the stigma 4- to 8-radiate. Fruit a mediocre pyx containing few to several seeds, dehiscing through deliquescence or irregular shredding of the operculum. Embryo differentiated, with fleshy coty- ledons and minute hypocotyl and plumule.
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Habit
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Trees
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Note
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About 40 to 50 species from Costa Rica to Peru and Brazil; one or two species in the Lesser Antilles.
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Key
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a. Calyx lobes clearly differentiated, 6- to 7-cleft to the hypanthium, foliaceous, accrescent and persistent in fruit; fruit relatively small, longitudinally ribbed or winged, probably dry and dehiscent through shredding of -the operculum. b. Flowers supported by a slender 2-bracteolate pedicel, conspicuously ferruginous-tomentellous, the petals 1.5-2.0 cm. long; pyx turbinate, nearly twice as broad as long, densely ferruginous-tomentellous; leaves essentially entire. -.---------------------------------------------------------1. G. PLEUROCARPA bb. Flowers without a proper pedicel, the hypanthium immediately sub- tended by 2 small bracteoles, indefinitely ferruginous-papillate, the petals 4.0-4.5 cm. long; pyx cylindric-campanulate, about as long as broad, glabrous or essentially so; leaves rather obscurely undulate- serrate. -. G.. BAC--------........................................... 2. G. BRACHYCARPA aa. Calyx reduced to a more or less obscurely 4- to 6-lobed ring, obscure and not accrescent in fruit; fruit relatively large, not clearly ribbed or winged, probably more or less pulpy and dehiscent through deliquescence of the operculum. b. Leaves mediocre, up to about 4 cm. long, with proportionally long petioles, oblong-lanceolate; flowers about 6 cm. in diameter; pyx not very fleshy, the pericarp about 5 mm. thick, the operculum large, as broad as the body of the fruit. .- - -- - - 3.. G. NANA bb. Leaves large, up to about 10 dm. long, with proportionally short petioles, elliptic-oblanceolate; flowers 10-15 cm. in diameter; pyx very fleshy, the pericarp about 5-10 mm. thick, the operculum small, about one third as broad as the body of the fruit.- -... -.- 4. G. SUPERBA
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Note
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In the strict sense, Linnaeus' Gustavia would embrace only the last two species of the key and Aublet's Pirigara the first two. It is indeed a great temptation to separate the two groups generically, but it is resisted here for the very cogent fact that we must qualify the description of the fruits by the adverb "'probably." Aublet himself, however, describes the fruit of Pirigara hexapetala (- Gustavia hexapetala (Aubl.) Sm.), which would coincide with the former group, as "seche"I while Miers (loc. cit. p. 159) reports that in Gustavia, supposedly of the latter group, "on the ripening of the fruit, the dissepiments and placentae become re- solved into a pulp, which envelopes the seeds, all escaping together with the decay of the operculum [italics ours]." Whether the fruits differ or no, it is clear that such recent authors as Eyma (in Fl. Surinam. 31:121. 1934) and Pittier (loc. cit. 2. 1927) err in characterising the fruits as indehiscent without any qualification. It is impossible to understand why Pittier, particularly, could actually key Gustavia upon such a statement im- mediately before describing G. pleurocarpa Pitt. and G. brachycarpa Pitt., the type collections of which, gathered by Pittier himself, include abundant dry, empty pyxes with perfectly round opercular openings. I have also seen similar fruits with very definite opercular openings upon specimens of G. hexapetala, as has my friend Noel Y. Sandwith, of Kew, for G. laciniosa. Insofar as floral characters distinguishing Pirigara and Gustavia are concerned, other than the natures of the calyx, I have been able to observe only that the anthers of Gustavia are proportionally more elongate and deeply sulcate than those of Pirigara. The flowers themselves of Gustavia, however, are most usually densely cauliflorous while those of Pirigara are more in smaller terminal or subterminal clusters. In short, the problem appears insoluble upon our present evidence, and is commended to the attention of future collectors in the field.
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