Michael H. Grayum

Relationships among time, frequency, and duration of flowering in tropical rain forest trees.

Flowering patterns are defined by the timing, duration, and frequency of flowering. Plants, particularly in the tropics, vary enormously with respect to these main variables of flowering. We used data from 302 tree species in a wet tropical forest to test a series of predictions regarding timing, duration, and frequency of flowering and examined the effect of each variable on the other two. Because timing, duration, and frequency of flowering can be constrained by phylogeny, we analyzed the data before and after considering phylogenetic effects at the level of family. Flowering activity peaked in the first wet season from May to July, refuting our prediction of peak flowering during the dry season. Our prediction that most species should flower several times a year was supported when species flowering more or less continually throughout the year were included in this category. Our prediction that supra-annually flowering species should be the least frequent was also supported with some qualifications. As we predicted, species flowering several times a year bloomed relatively briefly per flowering episode. Our prediction of shorter flowering duration for species flowering in the dry season and for those with a temporal separation between flowering and vegetative growth was also supported. Furthermore, supra-annually flowering species flowered for a shorter duration than annually flowering species and had a higher probability of flowering in the dry season compared to episodically or annually flowering species. Phylogeny significantly constrained variation in flowering frequency, but not in flowering time or duration, among confamilial species.

Systematic embryology of the Araceae

Embryological data of systematic significance to the family Araceae are reviewed and analyzed, with special attention given to the determination of character-state polarities. Character-states considered primitive within the family include: presence of endothecial thickenings; binucleate, starchless pollen; anatropous, crassinucellate ovules with a thick nucellar cap and a single, unbranched funicular bundle; solanad or caryophyllad embryogeny; helobial endosperm development, with 2–8 cells in the chalazal chamber andab initio cellular division in the micropylar chamber; and endosperm present in ripe seeds. The phylogenetic implications of these conclusions are discussed, and promising avenues for future research are indicated.ResumenSe revisan y se analizan los datos embriológicos de importancia para la familia Araceae, haciendo énfasis en la polarización de las facetas de los caracteres. Las facetas consideradas como primitivas dentro de la familia incluyen: existencia de engrosamientos endotécicos; polen binucleado y sin almidón; óvulos anátropos y crasinucelados con caliptra nucelar gruesa y un solo hacecillo funicular no ramificado; embriogénesis de tipo solanáceo o cariofiláceo; desarrollo helobial del endosperma, con 2–8 células en la cámara calazal y división celularab initio en la cámara micropilar; y endosperma presente en las semillas maduras. Se discute el significado filogenético de estas conclusiones, y se indican las lineas de investigación más prometedoras para el futuro.

Phylogenetic implications of pollen nuclear number in theAraceae

Data on pollen nuclear number are presented for 74 of the 111 currently accepted genera of theAraceae — one of only three monocot families in which both bi- and trinucleate pollen are known to occur. Binucleate pollen, which characterizes 65% of aroid genera, is regarded as the primitive type inAraceae and monocots as a whole. The trend toward the trinucleate condition appears to be irreversible, and to have occurred many times within the family.Syngonium becomes the sixth angiosperm genus in which both character-states are known to occur; otherwise, the character is highly conservative at the generic level. Pollen nuclear number shows no evident correlation with pollen size, starch content or pollinator type.

A New Monstera Species (Araceae) of Economic Importance from Honduras

Monstera maderaverde Grayum & Karney (Araceae: Monsteroiodeae: Monstereae), here described as new to science, is an endemic, secondarily hemiepiphytic species from Honduras producing a saleable product. Remarkably, it has been completely missed in scientific identification. Many tropical communities worldwide employ fibrous Araceae for household applications and commercial sale. Hemiepiphytic Araceae are important medicinally and ornamentally in Bolivia, and pendent Araceae roots have been used for basket-weaving in Mexico (Monstera deliciosa Liebm., Syngonium podophyllum Schott) and Tonga (Epipremnum pinnatum [L.] Engl.), while Epipremnum cermaense has been used in canoe outrigging on the Indonesian island of Halmahera (Acebey et al. 2010; Hettinger and Cox 1997; Martínez-Romero et al. 2004). Further, basket-weaving and construction applications of aroids belonging to the genus Heteropsis have been documented in Amazonia (Knab-Vispo et al. 2003). In the case of Monstera maderaverde, pendent, fibrous roots 2–10 m in length are removed from plants growing in or near the canopy, with stems, leaves, and the supporting tree left intact. The roots are peeled, dried, and made into commercial products such as hats (Figs. 1, 2) and visors, containers for flowers, jewelry, and tortillas, wastebaskets, key-chains, furniture, mirror frames, and figurines. The raw material is known locally as “mimbre” (i.e., “wicker”). Honduras is within the Mesoamerican biodiversity hotspot (Myers et al. 2000), but has been poorly studied floristically, with neither a national flora nor any comprehensive treatment of Honduran Araceae yet available. Florulas of two Atlantic coastal regions, the Lancetilla and Aguán Valleys, were published by Standley (1931) and Yuncker (1940), respectively. Only one new species of Araceae was described in the latter work, and just three (none in Monstera) have been described from Honduras since 1940. Croat (1998) noted only one endemic species of Anthurium (Araceae) in Honduras, relative to far more in Costa Rica and Panama. The recognition of Monstera maderaverde suggests that a lack of research effort may be partly responsible for this apparent dearth, and it is probable that the forests where M. maderaverde occurs are of high biodiversity significance. The understudied nature of the Honduran flora is especially troubling given recent deforestation trends. Carr (2005) acknowledged Central America as the world region with the highest deforestation percentage in the latter half of the 20 century, with Honduras accounting for the regional peak during 1990–2005 (DeClerck et al. 2010). From 2005–2010, forested land area in Honduras was estimated to have been reduced from 5,744,000 ha to 5,150,000 ha (Oqueli et al. 2010). This trend is especially problematic for species showing an affinity for continuous primary forests, such as climbing epiphytes (Koster et al. 2009). The potentially benign harvest of a useable species like Monstera maderaverde could provide an economic incentive to conserve remaining forests.

New Taxa of Caladium, Chlorospatha, and Xanthosoma (Araceae: Colocasioideae) from Southern Central America and Northwestern Colombia

Six new infrageneric taxa of Araceae, subfamily Colocasioideae, are described. Chlorospatha hammeliana is described from a restricted area of Panama, C. croatiana ssp. croatiana from Costa Rica and Panama, and Caladium lindeni (Andr6) Madison var. sylvestre from Panama and Colombia. These represent the first reported indigenous occurrences of the genera Caladium and Chlorospatha outside of South America. In addition, Chlorospatha gentryi and C. croatiana ssp. enneaphylla are described from northwestern Colombia. Chlorospatha croatiana and C. gentryi are the fourth and fifth species of their genus known to have compound leaves; a key is provided to all five. A brief review of generic distinctions within the tribe Caladieae precedes the description of the second known peltateleaved species of Xanthosoma, X. caladioides, from eastern Panama. The tribe Caladieae (sensu Madison, 1981), belonging to the subfamily Colocasioideae of the overwhelmingly tropical family Araceae, consists of six genera and 70-7 5 species, all confined to the New World. Three of the genera, Aphyllarum, Jasarum, and Scaphispatha, are monotypic and of restricted distribution in South America and will not be considered further in this paper. The remaining three genera, Caladium, Chlorospatha, and Xanthosoma, comprise the bulk of the species and range more widely, though only Xanthosoma has been heretofore reported to extend beyond South America (Croat, 1979; Madison, 1981). The Caladieae appear to be especially diverse in the Andean regions of northern South America, and recent work on newly available collections from that area (Madison, 1981) has led to the clarification of generic concepts in the group. These refined concepts have, in turn, facilitated the placement of new taxa collected in South America and other regions, including those described below. CALADIUM Caladium lin-denii (Andr6) Madison is well known in cultivation as an ornamental plant with whitish or silvery leaf venation. This species is more commonly, but improperly, known as Xanthosoma lindenii (Andr6) Engl., the transfer to Caladium having been made only recently (Madison, 1981). It was first described, as Phyllotaenium lindenii Andr6, in 1872, from plants supposedly collected in Colombia; although persisting in cultivation, the species was not found again in the wild until 1939, when a form with plain green leaves was collected in Choc6 Department, Colombia (Killip 35140, COL). Subsequent collections have extended the known natural range of this species-and consequently of the genus Caladium-into central Panama. All collections of the plain-leaved form have, until recently, either been misidentified or left

PRELIMINARY REPORT ON THE FLORA PROJECT OF LA SELVA FIELD STATION, COSTA RICA'

Finca La Selva is an intensively studied biological field station with a poorly known flora. Presently we can account for about 1,500 species of vascular plants but the flora may contain as many as 2,000. Although collecting has been nearly continuous since the beginning of the project in the summer of 1979, we are still finding novelties. Experience at La Selva has driven home the fact that certain genera of both bulky and inaccessible plants have been habitually ignored by botanical collectors in the tropics. The wet Caribbean lowlands of Central America have themselves been relatively inaccessible and ignored. General collecting throughout the region is urgently needed. HISTORY Finca La Selva is a 730 hectare4 biological field station owned and operated by the Organization for Tropical Studies (OTS), which is a consortium of North and Central American universities. The station is located near the confluence of the Puerto Viejo and Sarapiqui rivers in the province of Heredia in the Caribbean lowlands of northeastern Costa Rica. The property encompasses about 650 hectares of primary forest in addition to 80 hectares of disturbed land, including old pasture, abandoned cacao and pejibaye (peach palm) plantations, 25-year-old successional woods, and regularly maintained one- through five-year-old successional plots. In the Holdridge Life Zone system, the vegetation is classified as Tropical Premontane Wet Forest (Holdridge et al., 1971). The average annual rainfall is about 3,900 mm. The elevation varies from 100 m along the Rio Puerto Viejo on the north edge of the property to 220 m in the ridge-dissected southern section (Petriceks, 1956). Thus, the altitudinal range from one end of the property to the other, a distance of about 3.4 km, exceeds that from the Caribbean coast to the La Selva field station, a distance of about 55 km. For the last 12 years the station has been the annual site of as many as three OTS courses in tropical ecology as well as a number of courses offered by other institutions. The site has served almost continuously for the last 25 years as base for many researchers and has been particularly attractive to plant ecologists. A bibliography of published papers based on work done at La Selva contained about 200 entries by fall of 1981. Nevertheless, until recently fewer than half the species of vascular plants now known to occur at the station had been even tentatively identified or otherwise accounted for. The need for a means to identify plants at La Selva has been ever-present. Standleys Flora of Costa Rica (1937-1938) is much out of date and provides only

Chlorospatha kressii (Araceae), a new compound-leaved species from Chocó department, Colombia

The Andean-centered aroid genus Chlorospatha, belonging to the tribe Caladieae of the subfamily Colocasioideae, was regarded until a decade ago as monotypic, consisting only of C. kolbii Engl. (an enigmatic compound-leaved species still known only from a few century-old illustrations and a single, fragmentary herbarium specimen). In 1981, Madison redefined the genus to include the four species previously comprising Caladiopsis, which differed from Chlorospatha only in having simple rather than compound leaves. Since that time many new species have been described from Colombia, Ecuador, and Peru, bringing the total for the genus to 15 by 1986. Grayum (1986) predicted that many more species remained to be discovered and that, judging from intriguing but sterile herbarium specimens, the Choc6 region of Colombia would be a rich source for such novelties. The present paper describes a distinctive new Chlorospatha, not previously represented by sterile material, from Choco Department.

Lectotypification and Reinstatement of Stachytarpheta friedrichsthalii (Verbenaceae), with Notes on the Lectotypification of S. indica

Abstract.  Certain material of Stachytarpheta Vahl (Verbenaceae), mostly from the Caribbean coast of Central America (from Honduras to Panama), apparently related to S. calderonii Moldenke and S. indica (L.) Vahl, but consistently misidentified as S. jamaicensis (L.) Vahl, has been identified as S. friedrichsthalii Hayek. Examination of both syntypes of the latter name (Fendler 219, MO; Friedrichsthal 466, W) confirms that the calyx is more or less bilobed, versus 4-toothed in S. jamaicensis, under which S. friedrichsthalii has erroneously been placed in synonymy. One of the two sheets of Friedrichsthal 466 (W)—the one corresponding to Field Museum negative 34320—is chosen as the lectotype. Contrary to recent suggestion, the latest lectotypification of Verbena indica L. (on a portion of LINN 35.1) is found to be consistent with its protologue, and the consequent synonymy of S. angustifolia (Mill.) Vahl under S. indica is here accepted. Furthermore, it is suggested that S. friedrichsthalii may also be the correct name for some African material that has been included in S. indica (in much the same way S. friedrichsthalii has been found among Central American material of S. jamaicensis).

Two New Trifoliolate-Leaved Species of Cucurbitaceae (Cucurbiteae) from Central and South America

Abstract Two new species of Cucurbitaceae, tribe Cucurbiteae, with trifoliolate leaves are described from Costa Rica, one each in Cayaponia Silva Manso and Cionosicys Grisebach. Cayaponia hammelii Grayum, with large, pendent staminate flowers, ranges from Costa Rica to Pacific Ecuador, while the exceptionally large-fruited Cionosicys guabubu Grayum & J. A. González is restricted to Nicaragua, Costa Rica, and central Panama. Both of these new species have sometimes been misidentified as Cayaponia granatensis Cogniaux, a species with trilobate leaves that is dubiously present in Mesoamerica. The distinction between Cayaponia and the similar Cionosicys is discussed in some detail, and a key is provided for all species of Cionosicys with validly published names.

The identity and typification of Guarea hoffmanniana C. DC. (Meliaceae)

Morphological evaluation of a previously overlooked isotype, together with an improved comprehension of its Costa Rican type locality, permit the definitive application of the long-misunderstood name Guarea hoffmanniana C. DC. to the species known most recently as Guarea macropetala T. D. Penn. The former name is lectotypified on the newly found isotype, and the latter name is formally relegated to taxonomic synonymy. All collections examined for this study are cited.