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AND REINSTATEMENT EXPANSION OF THE GENUS PERISTETHIUM (LORANTHACEAE 1 ) Volume Number 4 543 98, Kuijt 2011 Reinstatement and Expansion of Peristethium herewith proposed realign the species involved on the several pairs of partly persistent, chaffy bracts is to Van in the archeri-S. leptostachyus intergeneric bridge that envelop the young inflorescence, but C. as a separate genus, for which the name Peristethium Tieghem, without providing any details, also stated available. This includes the assignment of several that the stamens are of one type; in reality, they are is Van somewhat species to Peristethium thus far resident in Struthan- always placed at two different heights. thus S aequatoris Kuijt, leptostachyus, Tieghem’s errors (as applied to the only species then S. S. . ( & recognized) were repeated by Engler and Krause polystachyus (Ruiz Pav.) G. Don, and S. tortistylus who added namely a further one, the Kuijt) or in Cladocolea (C. archeri, C. nitida Kuijt, C. (1935), shape which threadlike of the filaments, of are primaria and all peruviensis Kuijt, C. Kuijt, C. rorai- As newly said to be of equal length. indicated in the generic mensis (Steyerm.) Kuijt). Additionally, five discovered species from Andean South America are diagnosis below, bisexual flowers are characteristic of known and As now at least one species not to the above authors, herein described illustrated. constituted and anthers are sessile or nearly so, threadlike by these 15 species, the genus Peristethium demon- filaments not being present. and strates coherent, structural, geographic integrity. The rationale for recognizing Peristethium as a Several features, seen in individual species, are segregate from Struthanthus and as here circum- New unique or nearly so in World Loranthaceae, even scribed based on several structural characters. The is in the family generally, and include an inflorescence among most prominent these the above-mentioned is most often terminated by a single flower that is many development conspicuous of several to pairs of preceded by at least one pair of lateral 1 -flowered chaffy scale leaves the base and along the at units called monads, an inflorescence bearing a inflorescence axis, the axial ones (bracts) subtending and monad. Most triads of the scales along the fertile partially caducous) scale leaves, and extremely small, axis tend to be caducous, but basal scale leaves often mostly sessile and basifixed anthers that are No species of Struthanthus possess such persist. positioned near the tips of the subtending petals. scale leaves, but several other, unrelated Neotropical The combination of these features unique in is much Loranthaceae show similar but smaller and Loranthaceae. Peristethium includes both dioecious mostly deciduous scale leaves along the lower some species as well as with bisexual flowers; Panamanthus inflorescence axes, as in Kuijt. In the some unusual in Neotropical Loranthaceae, species Old World, a similar, independent evolution of are tetramerous and others hexamerous. modified scalelike leaves below the flowers has In retrospect, can be seen that Peristethium as a it occurred, as in Diplatia Tiegh., Tolypanthus (Blume) natural assemblage has been glimpsed in the past Blume, and several other genera (Kuijt, 1981b). The without being properly appreciated. protologue However, the scale leaves in these Old World genera of Struthanthus tortistylus Kuijt suggested an affinity much and are larger, often brightly colored, not and P. leptostachyum (Kunth) Tiegh. P. poly- to & stachyum (Ruiz Pav.) Kuijt, these species then be distinguished from the more inconspicuous pairs being placed Struthanthus still in (as S. leptosta- of prophylls at the base of axillary ramifications of A and chyus polystachyus Kuijt, 2003a). study of S. ; foliar sclerenchyma pointed & ir Steyerm. and P. sonorae Watson) Kuijt (Kuijt, (S. suggesting taxonomic connections between P. ar- 2009). cheri (A. C. Sm.) Kuijt, P. leptostachyum, and the A second important generic character in Peri- new two nomenclatural combinations presented stethium the occurrence in each inflorescence of a is here, P. primarium (Kuijt) Kuijt and P. roraimense commonly single morphologically terminal flower, (Steyerm.) Kuijt Cladocolea primaria and (as C. & roraimensis; Kuijt Lye, 2005). Parallel statements The inflorescence thus determinate. Paucity of is are to be found in the protologue of C. primaria materials has prevented me from confirming this The (Kuijt, 1987a). present treatment resolves such some aspect in species accepted here for Peri- stethium. In at least one unrelated species, Struthan- & Van Tieghem’s protologue of Peristethium (Van thus deppeanus (Schltdl. Cham.) G. Don in Mexico, Tieghem, 1895) is exceedingly sparse and based on the same determinate pattern exists (Kuijt, 1981b), He Kunth the original Loranthus leptostachyus alone. but elsewhere in small-flowered genera in the repeated Martius’s error by describing the flowers as A bisexual, even though this had been corrected by third important generic feature in Peristethium is Eichler (1868). The new genus was founded primarily the sessile or nearly sessile, exceedingly small 544 Annals of the Garden Missouri Botanical known anther, inserted well above the middle of the petal (Kuijt, 1975b). In Mexico, also in it is synonym that bears Struthanthus characteristically has Struthanthus in fact, the generic Spirostylis it. ; now larger, versatile anthers on long, slender filaments. was based on this stylar twisting in what is The other small-flowered genera in the Loranthaceae known as S. interruptus (Kunth) G. Don (Kuijt, possess entirely different androecia, especially Den- 1975a). Struthanthus from Ecuador (2003a) tortistylus many dropemon (Blume) Rchb. (Kuijt, 2011a) and was published before was realized that contorted it species of the genus Passovia H. Karst.; the latter styles are also characteristic of female P. polysta- have minute anthers, but can scarcely be held as chyum a fact not previously mentioned in the , The One related to Peristethium. small size of the anthers, literature. further species with strongly contorted and the prominent sterile anthers in male plants, for styles, an as yet undescribed species of Struthanthus example, of P. leptostachyum can be problematic in from Peru, has recently been discovered. Thus we can , the determination of sex, as shown by the errors made be assured that there are at least three instances in by Van Tieghem and Engler (1895) (1897) in which this curious, unexplained feature has evolved referring to that species as having bisexual flowers. independently in Neotropical, small-flowered genera. Nevertheless, species with bisexual flowers as well as The phenomenon not known from other Lorantha- is dioecious species exist in Peristethium. Further, the C eae in either the New or Old Worlds, with the slender shape of the seedling in Peristethium lacking solitary exception of Ileostylus micranthus (Hook, f.) , a swollen haustorial pole, has also emerged as a New Zealand The Tiegh. of (Barlow, 1966). biological most contrasting feature vis-a-vis other small-flow- known, significance of contorted styles not but is it ered genera. Finally, the existence of foliar scleren- may bear a relation the extraordinary behavior of to chyma common is a denominator for those species the embryo sac known from Foranthaceae generally & that have been investigated (Kuijt Lye, 2005). The see Kuijt, 1969, for a summary). ( profusion of stellate foliar sclereids is especially As now constituted, Peristethium also has con- much remarkable in P. roraimense where of the leaf yincing geographical species range from integrity: its , mesophyll such consists of cells. Amazonian Andes Bolivia north through the into The variation in inflorescence structure seen in Costa Rica, with two endemic, highly localized Peristethium in general agreement with the is on Roraima and Pakaraima Moun- outliers Mt. the evolutionary trends previously outlined for the tains (pig. 1). It is generally accepted that the upper Loranthaceae (Kuijt, 1981b). In that study, I Venezuela and Guyana regions of the lepuis of concluded that the evolution of their inflorescences environmentally correspond to the paramo life zone of led from monads to aggregation as triads, and that lhe norlhern Andes (Berry et al., 1995), and the this process begins at the base of the inflorescence. existence of the two rare species, P. roraimense and This latter tendency corresponds to the change from p dum Roraima mtl (Kuijt) Kuijt, in the Mt. area is plants with bisexual flowers a dioecious condition, to The no unexpected. phylogenetic of affinities t and that hexamery was derived from Letramery. With Peristethium with other small-flowered genera in the may we regard to Lriadization, see all stages in the Loranthaceae are at present unclear, although the process represented in extant species of Peristethium. coherence of Psittacanthinae, which also includes the For example, P. archeri P. peruviense (Kuijt) Kuijt, large-flowered genera Aetanthus (Eichler) Engl, and , and P. roraimense have strictly monadic inflores- Psittacanthus Mart., has received molecular affirma- cences. In P. primarium P. palandense Kuijt, and & (Vidal-Russell Nickrent, 2008; Nickrent , lion et al., several others, triads are present basally while among However, 2010). the precise relationships the monads are found subterminally and variably. various genera remain be elucidated. Morpholog- l0 may Finally, P. confertiflorum have only triads, with mformallon especially the occurrence of tetram- icjd , some the additional, unanticipated production of eroug flowers? determinate inflorescences, and mo- pentads. With the exception of P. primarium all , nadg lacking bracte present an oles, at tetramerous species also exclusively have monadic n n- r rr- •, r .1 ri j J attimty reri•s,tetnium with Ltaaocotiea. oi inflorescences, thus combining two putatively ances- conditions. tral Taxonomic Treatment The curiously contorted described and style illustrated for Peristethium polystachyum and P. Peristethium Tiegh., Bull. Soc. Bot. France 42: 175. TYPE: tortistylum Kuijt (Kuijt) has equivalents in several 1895. Peristethium leptostachyum other Neotropical genera. The majority of Mesoamer- (Kunth) Tiegh. [= Loranthus leptostachyus ican species of Cladocolea show this feature, seen Kunth, Nov. Gen. Sp. [H.B.K.] (quarto ed.) 3: more strongly in the female flower than the male 440. 1818 (1820)]. l r<Ti 11a. 550 Annals of the Garden Missouri Botanical much cm 13a. Infructescences crowded; leaf-bearing internodes 1 thick, developing numerous slender, elongated lenticels; western Colombia colombianum 4. P. 13b. Infructescences not obviously crowded; leaf-bearing internodes mostly cm 0.5 thick or less, developing pustular lenticels; Costa Rica to Ecuador. when 14a. Leaves darkening dry; fruit obovoid; pollen heteropolar, with apocolpial field on one pole; southern Andean Ecua- dor 8. P. lojae when 14b. Leaves remaining green dry; fruit ellipsoid; pollen isopolar, lacking apocolpial Costa Rica Ecuador field; to P. leptostachyum 7. 1. Peristethium aequatoris (Kuijt) Kuijt, comb. nov. of the inflorescence, but they are small and early Basionym: Struthanthus aequatoris Kuijt, FI. caducous, and are obvious only at the earliest stages Ecudaor, 24: 149-151. 1986. TYPE: Ecuador. of inflorescence development. Similar, but somewhat Pichincha: Canton Quito, along rd. betw. smaller, caducous chaffy bracts subtend the triads & km Tandayapa Mindo, 9-10 beyond Tan- and monads and can be seen at the tip of expanding dayapa, 2530 m, 16 Dec. 1979, T B. Croat inflorescences. In the protologue was suggested that it '. 49355 (holotype, MO-3096226!; isotypes, UC- the species might also be present in neighboring 1956802!, UC-1956803!). Figure Colombia. This indeed the case, as numerous 3. is below collections cited indicate. Plants dioecious, leggy, sparsely branched, gla- brous; internodes straight, slightly quadrangular to Additional specimens examined. COLOMBIA. Caqueta: km N 63 carinate, smooth without lenticels, to 9(13) cm; of Florencia near border with Huila, Gentry et al. 9181 (MO). Choco: Cerro del Torra, Silverstone-Sopkin et al. bearing occasional basal epicorlical roots. Leaves to 4454 (MO, UC); Ansermanuevo-San Jose del Palmar, carr. X 12 10 cm, broadly lance-ovate nearly thin, to border of Valle del Cauca, Alto del Galapago, Forero et al. elliptical, apex obtuse to abruptly attenuate-cuspidate 2882 (MO). Narino: Mpio. Ricuarte, Corregimiento Chu- or slightly acuminate, base mostly truncate, venation cunez, Reserva Natural La Planada, Roldan 1603 (UC); 7 & km W, from Chucunes, 5 N, 78 Gentry Keating 1 1 pinnate, evident, with 2 to 4 or more lateral veins km 59728 (MO); Reserva Natural La Planada, a 7 de reaching at least halfway to the apex, midvein running Chucunes, Benavides 8709 (MO); Corregimiento Chucunes, into the apex; petiole 1—1.5 cm. Inflorescences 1 to 3 Reserva Natural La Planada, Roldan 1601 (HUA, MO), 5—14 per leaf axil, each inflorescence largely triadic, 1602 (MO), 1603 (MO); trail from La Planada to Pielapi, 1°4 / N, 78°2 / W, Gentry 63655 (MO); de Osos, Isla los cm; inflorescence bearing 8 to 14 pairs of triads et al. 1°10 N, 77°50 / W, Benavides 9733 (MO); trayecto San followed by pair of monads, and 1 terminal flower; 1 Isidro-La Planada, 1°10 N, 77°58 / W, Benavides 9230 triad and monad peduncles 1—2 mm, median flower of (MO). Riseralda: Santa Rosa de Cabal, along rd. to mm; & on triads sessile, lateral flowers pedicels ca. 1 Termales, borders of Rio San Eugenio, Wijninga Wolf W ± km 548 (UC). Santander del Sur: 4 below Palo Blanco of basal inflorescence bracts several pairs, small, ECUADOR. Velez, Laer 10103 (MO, UC). Carchi: et al. persistent; floral bracts and bracteoles caducous; 0 lFW, Mira, 0°50'N, 78 Tirado 1282 (UC); above et al. 1—2 peduncle cm. Elowers hexamerous, flower buds & Maldonado, Van der Werff Gndino 10858 (UC); Tulcan— W mm; & yellowish or greenish white, apex rounded, 6.5 Maldonado, of Tufino, Van der Werff Gudino 10703 km mm; petals ca. 4.5 male flower with anthers nearly 1 (UC). Cotopaxi: Canton Sigehos, 35 de Sigchos, mm, 2 different heights near the bud apex, not 0°32 / 4 // S, 78°58 /43 // W, Ramos et al. 6862 (UC). Morona- at Santiago: Canton Cualaquiza, Cordillera del Condor, and overlapping, with slender style undifferentiated SW 3°27 / S, 78°22'W, Gentry 80344 (UC). Napo: of stigma; female flower as the male but more slender, Cosanga, Orellana, Parque Nac. Yasuni, O^O^S, mm, sterile anthers 1 well-formed and even dehiscing; 77°52 / W, Dik 476 (UC). Pichincha: vie. of Bellavista km style 4 mm; stigma capitate. Fruit an ovoid berry, dull Scientific Research Station and 1.2 S of Bellavista, 0.3— W km Tandayapa-Mindo OOTUlb'S, mm mm of 1 rd., 10 and when orange-red, 5.5 thick mature. to km 78°41 / 07 // W, Croat 96475 (MO, UC); 1.7-2.1 et al. beyond 0°01 / 02 // 78°44 / 07 // W, Croat 94632 Bellavista, S, Distribution. Collections of Peristethium aequa- km (MO, UC); Tandayapa-Mindo 7.2 S of Tandayapa, rd., toris have been seen only from Colombia. It grows in 0°0 / 24 // S, 78°40 / W, Croat et al. 96505 (MO, UC); vie. of elevations ranging from 160 4000 m. Bellavista, Km. 12 on rd. from Tandayapa to Mindo, to 0°01 / 02 // 78°44'49// W, 94573 (MO, Croat UC); S, carr. Loma Nanegalito-Armenia, de San Jose, La Vuelta Brava, The Discussion protologue of Struthanthus ae- . & 0°5'N, 78°40 / W, Zak Jaramillo 3221 (K ex MO); carr. some quatoris (Kuijt, 1986) contained errors that Quito-Mitad del Mundo, Calacali-Nanegalito, betw. Cal- must be corrected. Most importantly, Peristethium & acali Nanegalito, Freire-F. 631 (NY); Canton Quito, et al. aequatoris does indeed have chaffy bracts at the base 0°4'N, 78°39 / W, Webster et al. 30484 (UC); old rd. Quito- W km Santo Domingo de los Colorados, 6-11 of San Juan 0 ogallo, 0°17'S, 78 41'W, Freire-F. et al. 1514 (NY); old rd.