252 
ORIGINAL ARTICLES. 
rays. To a certain period the central ligneous bundles are dis¬ 
tinct.—Unger, F. Ueber den Bau und das Wachsthum des 
Dicotyledonen-stammes. St. Petersburg, 1840. Absch. v. On 
the Structure and Development of the Piperaceae. The order 
possesses both a central and peripherical vascular system. These 
traverse the internodes parallel to each other without anasto¬ 
mosis ; at the nodes they unite, forming a vascular plexus, in 
which buds and roots originate. The formation of the wood 
takes place solely through the peripherical vascular bundles, 
originating on their outer side, and consisting of new vascular 
fascicles, and their connecting prosenchymatous tissue. The re¬ 
lation of the appendicular organs to the vascular system of the 
stem is described. The structure of Saururus, Houttuynia , and 
Chloranthus is described.— Graudichaud. Becherches sur l’or- 
ganographie, &c., des Vegetaux, tab. xiv. 1. 2. 3. 5.—Miquel, F. 
A. W. Systema Piperacearum. 1843. On the Structure of the 
Stem in Peperomia magnoliaefolia , Tildenia , Piper , Artanthe , 
Chavica ; and the structure of the root, p. 7. Noting the 
occurrence of vascular bundles traversing the pith: in an 
adult stem of an Artanthe , about 20 of these are found in cross 
section; they are less crowded toward the centre of the pith. 
The wood is traversed by very numerous medullary rays, 
primary and secondary, and by dotted vessels.— vide also Miquel, 
in Martins’ 4 Plora Brasiliensis.’—Bindley, J. Veg. Kingdom, 
515.—Henfrey, A. Elements of Bot. 533. 
Chloranthaceae. Griffith, W. Notulae, iv. 383. 
Urticaceae. G-uillard, A. La Eamille des Urticees. Presse Scient. 
d. deux Mondes, iii. 305. Structure of the liber, ligneous fibres, &c. 
—Weddell, H. A. Monog. des Urticees. Paris, 1856. Anatomy of 
the Stem, p. 7. Ann. Sc. Nat. Ser. iv. 7, 309. G-enerally, its 
structure scarcely differs from that prevailing in Dicotyledons, 
though some are remarkable from the unusual development of 
certain tissues. In TJrereae the medullary plates are of great 
vertical extent, as also in a ligneous Pilea and in Plato stem a. 
The numerous vessels are dotted or transversely slit-marked. 
The liber-cells, delicate and much elongated, are united end to 
end, and disposed in close concentric zones, separated by paren¬ 
chymatous layers. The structure of the wood of Laportea gigas 
is described (p. 131) and figured (tab. iv.). Wood of Gesnouinia 
arborea, vide tab. iv. 10.— Urtica dioica. Schacht, H. Pflanzen- 
zelle, 250, t. xi.— Urtica. Chatin, Gr. A. Anat. comparee d. 
Vegetaux, Livr. iii. 9 (in note). Absence of medullary rays in.— 
Gecropia galmata. Miquel, E. A. W. Beobachtung fiber den Mark- 
kanal und die Quer-wande im Stamm der C. palmata , L. &c. 
Bull. Sc. Phys. etc. Neerland, 1838, 29-31.—Schultz, C. H. Die 
Cyklose, Nova Acta, 1841, xviii. Suppl. ii. tab. xiii.—Karsten, 
H. Ueber den Bau der. Nova Acta, 1854, xxiv. 79. With 2 
plates.—Miquel in Martius ‘Flora Brasiliensis,’ Urticineae, 140. 
