VERBENACEZ, 
SILVA OF NORTH AMERICA. 
105 
AVICENNIA. 
FLOWERS perfect; calyx 5-lobed, the lobes imbricated in estivation; corolla 
gamopetalous, 4-lobed, the lobes imbricated in estivation; stamens 4; disk annular ; 
ovary 1-celled; ovules 4, suspended. Fruit capsular, 1-seeded, the seed naked. Leaves 
opposite, entire, without stipules. 
Avicennia, Linnzus, Gen. 27 (1737). — A. L. de Jussieu, 
Gen. 108. — Endlicher, Gen. 638. — Meisner, Gen. 292. — 
Bentham & Hooker, Gen. ii. 1160. — Baillon, Hist. Pl. 
Upata, Adanson, Fam. Pl. ii. 201 (1763). 
Sceura, Forskal, Fl. Hgypt-Arab. 37 (1775). 
Racka, Gmelin, Syst. Nat. i. 245 (1791). 
xi. 120. 
Bontia, Loefling, Iter, 193 (not Linnezus) (1758). 
Halodendrum, Du Petit-Thouars, Roemer Coll. Bot. 201 
(1809). 
Seashore trees or shrubs, with stout pithy branches thickened at the nodes and marked by 
interpetiolar les, and long thick horizontal roots producing numerous short vertical thick and fleshy 
leafless stems rising above the surface of the soil. Leaves opposite, entire, coriaceous, persistent. 
Inflorescence cymose; flowers opposite, in centripetal pedunculate spikes or heads, closely invested by 
a bract and two bractlets, the peduncles solitary or in pairs in the axils of upper leaves and ternate 
on the ends of the branches. Bracts and bractlets similar, concave, acute, keeled on the back, apiculate, 
scarious and slightly ciliate on the margins, shorter than the corolla. Calyx cup-shaped, coated like the 
bracts and bractlets with canescent pubescence, divided nearly to the base into five concave ovate 
rounded lobes, persistent. Corolla campanulate, white, inserted on the obscure annular disk, the tube 
straight, cylindrical, shorter than the glabrous or tomentose spreading four-lobed limb, the posterior 
lobe usually somewhat larger than the others. Stamens four, inserted on the tube of the corolla, 
exserted ; filaments short, filiform, shghtly thickened at the base; anthers ovate, attached on the back 
near the bottom, two-celled ; the cells parallel, opening longitudinally. Ovary sessile, ovate, pubescent, 
one-celled, gradually narrowed into an elongated slender or abbreviated style divided at the apex 
into two lobes stigmatic on their inner face; ovules four, suspended from the summit of a free central 
placenta, orthotropous, without coats.* Fruit ovate, oblique, compressed, surrounded at the base by the 
persistent calyx, bracts and bractlets, apiculate at the apex. Pericarp thin, light green, villose-pubescent 
on the outer surface, longitudinally veined on the inner, opening by the ventral suture and displaying 
the enlarging embryo before separating from the branch, ultimately two-valved. Seed naked, exalbu- 
minous. Embryo filling the cavity of the pericarp, light green; cotyledons thick and fleshy, broader 
than long, slightly pointed, deeply cordate at the base, unequal, conduplicate; radicle elongated, clavate, 
retrorsely hirsute, inferior, descending obliquely and included between the lobes of the cotyledons, 
slightly attached near the apex in the bottom of the capsule to the withered columella by a minute 
papillose point ; plumule hairy.’ 
1 The ovary of Avicennia has been described as two-celled and DonatTia. Style elongated and exserted beyond the calyx 
as incompletely four-celled by the development of four wings from 
a central placental column, with a single ovule in each cell, and 
by Baillon (Hist. Pl. xi. 89) as one-celled with a four-winged cen- 
tral placenta and orthotropous ovules. In the flowers of Avicennia 
nitida from Florida that we have examined the ovary is one-celled 
with a free slightly flattened central placenta without trace of 
wings and bearing just below the summit four suspended ortho- 
tropous ovules attached laterally below their apex. 
2 Schauer (De Candolle, Prodr. xi. 699) groups the species of 
Avicennia in two sections. 
after the falling of the corolla ; limb of the corolla tomentose. 
Urata. Style abbreviated ; limb of the corolla glabrous on the 
upper surface. 
In the first group he places Avicennia nitida and Avicennia A fri- 
cana, and in the second Avicennia officinalis of the Old World and 
Avicennia tomentosa of the New World, which are now usually 
considered identical. The style of Avicennia officinalis is, however, 
sometimes well developed, and there are really no constant char- 
acters that can be relied on to distinguish the different species, 
which all bear a close resemblance to one another. 
