Primary Lateral Veins Research Articles

Spatial Distribution and Parasitism of Leaf Galls Induced byCallirhytis cornigera(Hymenoptera: Cynipidae) on Pin Oak

Callirhytis cornigera (Osten Sacken) is a gall wasp that has alternating agamic and sexual generations that develop in large, woody stem galls and small, blister-like leaf galls, respectively, on pin oak, Quercus palustris Muenchhausen. We assessed the spatial distribution of the leaf galls within leaves, shoots, canopy levels, and whole trees, and examined the relationship between leaf gall density and various tree parameters. Within leaves, proportionately more galls were located on primary lateral veins (59.5%) or midveins (38.1%), as compared with the petioles (2.0%) or secondary lateral veins (0.4%). As many as 18 galls occurred on individual leaves, but most leaves contained 0–4 galls. Some current-year shoots contained as many as 132 leaf galls, but most shoots had <20 galls. Leaf gall density did not vary significantly among heights within individual tree canopies, but was highly variable between trees. Leaf gall density at the whole tree level was not related to the tree’s rate of leaf- or shoot expansion. There was no relationship between tree-wide density of leaf galls and overall levels of foliar nitrogen, nonstructural carbohydrates, or protein binding capacity. The leaf galls supported a complex of hymenopteran parasitoids, including Aprostocetus spp., Pentastichus spp. (Eulophidae), Sycophila spp., Eurytoma sp. (Eurytomidae), Brasema sp. (Eupelmidae), and Ormyrus labotus Walker (Ormyridae). Parasitoids and inquilines accounted for nearly 80% mortality of C. cornigera within leaf galls; however, parasitism was only weakly density-dependent, regardless of spatial scale. Implications of these findings for management of C. cornigera are discussed.

Xanthosoma riparium (Araceae), a New Species from Goiás, Brazil

A new species of a caulescent Xan- thosoma (X. riparium) from Serra Dourada, state of Gois, Brazil, is described and illustrated. Xantho- soma riparium is most similar to X. mafaffoides G. S. Bunting, X. undipes (Jacquin) Schott, and X. maximilianii Schott, but differs from all these spe- cies in having fewer primary lateral veins that arise at a more acute angle. Moreover, the primary lateral veins in X. riparium are close to each other near the sinus, becoming more scattered toward the apex, not regularly scattered along the midrib like in X. mafaffoides, X. maximilianii, and X. undipes. This new species appears to be the only caulescent Xanthosoma known to be native to central Brazil.

A New Species of Philodendron (Araceae) from Central Brazil

Summary. A new species, Philodendron guaraense, is described from Central Brazil in the Federal District (Brasilia). Field observations of its ecology and reproductive biology are reported, together with some information on cultivation. The neotropical genus Philodendron Schott is the second largest in the Araceae, with over 500 species. Many species of Philodendron are widely used for ornamental purposes because of their exotic forms and beautiful foliage. However, numerous handsome species remain to be discovered in tropical America and one of these is the subject of this paper. Central Brazil has received little attention from aroid specialists and in view of this it is perhaps not so surprising that this new species was discovered in the Ecological Reserve of Guara, Federal District of Brazil (15049'08" - 15049'45"S, 47058'08''" - 47059'09"W), in one of the most densely populated areas of this region. The vegetation of the reserve consists mainly of permanent or seasonal marshes and gallery forests. Philodendron guaraense E. G. Gonf. sp. nov. P apparicioi G. M. Barroso affinis, sed ovarii loculis 7- 10 (non c. 13), petiolo 1 - 1.3 cm (non 2 cm) diametro, foliorum costulis posticis in sinu zona denudata 2 - 3cm (non 1 cm) longa instructis differt. Typus: Brazil, Distrito Federal, Reserva Ecol6gica do Guara, 27 Oct. 1994, Gonfalves 13 (holotypus UB; isotypi K, MO). Hemiepiphytic herb climbing to 2 - 6 m on host tree. Stem often pendent with erect tip; internodes greenish, 1.5 - 5 cm long, 4 - 5 cm diam.; intravaginal squamules not persistent, 1 - 2 mm long, 0.5 - 1 mm wide at base; adventitious roots abundant, chocolate brown, c. 5 mm diam. Prophyll deciduous, linear-lanceolate, 35 - 40 cm long, 5 - 5.5 cm wide at base, upper surface white, lower surface greenish. Petiole green, 55 - 65 cm long, 1 - 1.3 cm diam. in middle, flattened adaxially; sheath 5 - 6 cm long. Leaf blade triangular to ovate in outline, overall length 47 - 56 cm, overall width 23 - 28 cm, slightly coriaceous, upper surface glossy green, lower surface paler, margins yellow; anterior division 28 - 39 x 23 - 30 cm, apex cuspidate to acuminate, acumen 0.3 - 1 cm long, primary lateral veins 4 - 5 per side, arising at an angle of 60 - 700, interprimary veins conspicuous even in dried material; posterior divisions retrorse, 14- 15 x 11 - 15 cm, base sagittate to subcordatesagittate, primary acroscopic veins 2 - 3, primary basiscopic veins 2 - 3 and less

Two New Species of Araceae for the Guianas

Two species of Araceae from the Guianas are described. Philodendron billietiae, known from Guayana, French Guiana, and Brazil, is most closely related to P. acutatum. Xanthosoma granvillei, known only from French Guiana, is distinguished mainly by its large, blackish-drying blades. In order to complete the Araceae treatment for the Flora of Sail and the Flora of the Guianas it has become necessary to describe a number of new species. Descriptions of other new species of Araceae will follow. Philodendron billietiae Croat, sp. nov. TYPE: French Guiana. National Hwy. 2, CayenneRegina, vic. km 93, 100-150 m, 4018'N, 52010'W, Croat 74321 (holotype, MO 4343643-5; isotypes, B, BBS, BR, BRG, CAS, CAY, CM, F, G, GH, INPA, K, M, MG, NY, P, US, VEN). Figures 1-4. Planta hemiepiphytica; internodia brevia, usque 2.55 cm diam.; petiolus subteres, 25-57 cm longus, pallide aurantiacus-flavus vel viridi-flavus; lamina plus minusve anguste triangularis et sagittata, 30-85 cm longa, 8.121 cm lata; nervis lateralibus primariis 3-5 utroque; pedunculus 9.4-27 cm longus; spatha 17.5-18.5 cm longa, extus viridis; lamina intus alba; tubus intus purpurascens; spadix 16.5-18 cm longus; ovaria 6-11 locularia cum ovulis plus quam 10 in quoque loculo; affinis P. acutato Schott sed internodis proportione brevioribus, petiolo in vivo flavido vel ochraceo versus constanter viridi, lamina proportione angustiore basique lobis 35400 versus 60-75o divergentibus differt. Appressed-climbing hemiepiphyte, sometimes on rocks; stems about 1 m long, sometimes longer; internodes shorter than broad, 2.5-5 cm diam., light brown with irregular, weak, reticulate to mostly transverse fissures, turning yellow-brown; petiole scars to 4.5 cm diam.; cataphylls sharply D-shaped near apex, otherwise terete and unribbed or sometimes bluntly 2-ribbed, green to pale orange (sometimes brown, orange at base) or reddish, promptly caducous; roots moderately few, stout, ca. 5 mm diam., purplish brown, drying smooth, semiglossy, the epidermis often fissured; leaves usually clustered near the end of the stem, with erect spreading petioles and pendent blades; petioles broadly spreading, 25-57 cm long, averaging 40 cm long, broadly sulcate at base, obtusely flattened toward the apex, weakly angular near the apex, sheathed 4-8 cm at the base, firm, olive green to golden-yellow, pale yellow-orange or greenish yellow, when fresh, somewhat asperous and rather densely purplish-lineate, drying light yellow-brown to dark brown, typically closely fissured; blades pendent, narrowly triangular to narrowly ovate-triangular to oblong-triangular, 30-85 cm long, 8.1-21 cm wide (averaging 52 x 15 cm), 2.7-4 times longer than wide, averaging 3.4 times longer than wide, broadest at the base or near the petiole attachment, sometimes weakly constricted above the petiole attachment, 0.85-1.4 times as long as the petioles (averaging 1.07 times longer than petioles), moderately coriaceous, dark green and semiglossy above, much paler and matte to weakly glossy below; the margins often weakly undulate, hyaline or reddish; posterior lobes directed at about 1700 from the midrib (the two lobes separated by an angle of 35-40?), sometimes directed up slightly at an angle to the midrib, 8-22 cm long, 3-10 cm wide, about twice as long as wide; sinus much longer than wide, acute at apex, usually barely naked along the margin, but sometimes weakly naked up to 2.5 cm (the leaf tissue merging almost imperceptibly with the posterior rib); midrib flat to very broadly raised and paler (sometimes orangeyellow) with purplish dots above, narrowly raised and convex, yellow-brown to yellow-red or yellowgreen below; primary lateral veins 3-5, widely spaced and usually not prominent, weakly sunken to flat and yellow-green above, convex to weakly raised and sometimes reddish to purplish below, arising at 70-105? angle, mostly at nearly 900 angle, sometimes prominently down-turned at the midrib, sometimes splayed out at the midrib; minor veins numerous, moderately distinct when fresh, weakly raised above, flat and distinctly visible below, drying prominulous on both surfaces, with alternate veins frequently turned to join another minor vein just before the margin; cross veins inconspicuous; young leaves reddish. Inflorescences 1-3 per axil, erect; peduncle 9.4-27 cm long, ca. 1 cm diam., somewhat flattened, ribbed on one side, medium yellow-green, green-lineate to purplish-lineate; spathe 17.5-18.5 cm long, yellow-green to dark green outside, slightly paler toward apex, densely pale purplish-lineate on NovoN 5: 24-29. 1995. This content downloaded from 157.55.39.133 on Fri, 17 Jun 2016 05:24:48 UTC All use subject to http://about.jstor.org/terms Volume 5, Number 1 Croat 25 1995 Araceae from the Guianas u~ ?' IJL ~. r C.+ L

Leaf Venation in Eucalyptus and Other Genera of Myrtaceae: Implications for Systems of Classification of Venation

Two types of venation in leaves of eucalypts and other members of Myrtaceae are described and their ontogeny investigated in species of Eucalyptus. Primary seedling leaves of eucalypts have brochidodromous venation. A paramarginal vein is formed from the extensions of primary lateral veins and completed by the strengthening of commissural minor veins. Adult Eucalyptus leaves have intramarginal veins that are formed independently of the primary laterals which join them after their formation. The apparently brochidodromous venation of leaves of some species arises as a result of differential growth following the inception of intramarginal veins. Leaves with intramarginal veins are ontogenetically acrodromous. These conclusions are discussed in relation to the system of classification of venation put forward by L. J. Hickey. In particular, problems of ordination, affecting the terminology of veins, and of homology arising from the application of the rules of that system to the Myrtaceae, are dealt with.