EXPLANATION OF PLATE YIIL 
Fig. 1 . Vallisneria spiralis. A dioecious aquatic plant of Europe, America, and 
New Holland. Leaves radical, riband-like. A, staminate flower. Peduncles short,, 
terminated by a spike; ovate, spathaceous, remaining under water until the period for 
fertilizing the pistillate dowers. B, fertile plant, peduncles very long, spiral, uni- 
flowered. Flower spathaceous, floating. This singular plant, in which the two 
kinds of flowers are entirely separate, is fertilized by a curious provision of nature. 
When arrived at a mature state, the spiral peduncles of the pistillate flowers untwist 
themselves, and the flowers rise to the surface of the water ; the short spike of stam- 
inate flowers breaks off from, its peduncle; the flowers light upon the other plant, 
and shower their pollen over it. After this period, the pistillate flowers disappear be¬ 
low the surface of the water, where their fruit is produced. 
Fig. 2. Pistia stratiotes. The Duckweed tribe. A floating, stoloniferous plant. 
Leaves radical, spreading, flabeiliform. 
Fig. 3. Trapa natans.* * * § ( Onagrce .) An aquatic plant. Stem sub-merged, pro¬ 
ducing radical filaments of two sons; the one simple, filiform; the other ramified 
and pinnate ; they appear to be transformed leaves. The leaves are terminal, diverg¬ 
ing ; petioles broad, dentate. A, a plant soon after germination ; a, the fruit; Z>, peti¬ 
ole from one of the two cotyledons which remain enclosed in the fruit; c, the other 
cotyledon; root; e, stem. B, a plant more developed. 
Fig. 4. Butomus umbellatus. t Flowering-rush tribe. A plant which grows on 
the border of lakes and rivers. Leaves radical, erect, riband-like, pointed at the sum¬ 
mit. Scape rectilinear. Umbel simple, terminal, involucred. 
Fig. 5. Potamogeton compressum.t An annual, aquatic plant, common in brooks 
and ditches. Stem compressed, slender, leafy. Leaves alternate, linear. Spikes 
terminal, interrupted. Flower whorled. 
Fig. 6. Nelumbo nucifera.% An aquatic, perennial plant found in Egypt, India, 
and America. Leaves radical, peduneled, peltate, round, concave. Peduncle one- 
flowered. Calyx caducous. Corolla of many spreading petals. Stamens numerous; 
style, very short; stigma, like a cup; a, young leaves ; 6, flower; c, fruit. 
Fig. 7. Juncus conglomeratus.W The Rush tribe. (Juncce.) Stem very simple, 
aphyllous, rectilinear, vertical, terminating in a point. Panicle crowded, unilateral. 
Fig. 8. F ucus articulatus. IT The Sea-weed tribe. ( Algce .) A marine plant of 
the Atlantic Ocean. Frond cartilaginous, dichotomous, moniliform, articulated, each 
joint containing fruit. 
Fig. 9. Fucus digitatus. Stem simple, cylindric. Frond compressed, digitate* 
flabeiliform. 
Fig. 10. Fucus natans. A marine plant which, detaching itself from the rocks 
where it originates, floats in vast quantities upon the surface of the sea, forming 
islands which retard navigation. Stem filiform. Frond branching, lanceolate, den¬ 
tate. 
Fig. 11 . Fucus obtusatus. A marine plant of Cape Yan-Diemen. Frond com¬ 
pressed, coriaceous, branching, linear. 
* This plant is in the order Hydrocaryes of De Candolle, called the Water-chestnut Tribe. It is considered, 
by the late modifiers of the natural method, to be nearly allied to Onagrse, distinguished from it only by soli¬ 
tary, pendulous ovules. 
+ This is the leading genus in the order Butomeae, ofLindley ; byDe Candolle and Mirbel, placed in Alis- 
maceee, to which it is closely allied. 
I Of the order Naides of Jussieu, or Fluviales of more modern botanists. “In this order,” Lindlcy re¬ 
marks, “ we have the nearest approach, except in Pistiaceae, to the division of flowerless plants. The peri¬ 
anth is reduced to a few imperfect scales, the habit is almost that of Conifera), and there is in some of the 
genera, either a total absence of spiral vessels, or that form of tissue exists in a very rudimentary state.” 
The affinity of this order to Aroidese is manifest from the tendency of some species to produce a rudimentary 
spatha. Mirbel places this in the order Alismacoae. 
§ In the order Nelumbonooe of De Candolle by most writers united to Nymphffiaceee, with which it dif¬ 
fers in the structure of 1 he fruit, but agrees in the foliage and flowers. The fruit of one species of Nelumbium 
is thought to he the Egypt.an bean of ancient writers. 
n “This plant,” according to Bindley, “stands between Petaloideous and Glumaceous Monocotyledons, 
agreeing with the former in the floral leaves, having assumed the Verticillate state necessary to constitute a 
perianth, and with the latter in their texture. From Palms, independently of their habit, they are distin¬ 
guished by t he constant tendency to produce more than one ovule in each cell, and by tne embryo never be¬ 
ing remote from the iiiiiun. Juncus is an instance of a monocotyledonous plant having a distinct pith.” 
IT Lind ley describes tne order Algae as “aquatic, leafless, flowerless plants.”' He says, “ Whatever in¬ 
genuity may he employed in determining the relative degree of dignity in the vegetable creation between 
Fungi, Lichens, and Algae, it so ms to me that ihe conclusion constantly arrived at is, that Algae are only 
to be distinguished from the other two by their being in water, and that but for the influence which that me¬ 
dium exercises on them, they would be identical with Lichens oq the one hand, and Fungi on the other. 
Those who have ever examined the surfaces of stones constantly moistened by w^ater, the glass of hot-houses, 
the face of rocks in the sea, or of walls where the sun never shines, or the hard paths in the damp parts of 
gardens after rains, cannot fail to have remarked a green, mqcous slime, with which they are covered. This 
slime consists of Algre in their simplest state of organization, belonging to the genera Palmella, Nostoc, &;c. 
This slime is like a layer of albumen spread with a brush.” This albumen, Lindley says, may be the origin 
of either vegetable or animal matter, according to the nature of the corpuscles which penetrate or develop 
themselves in it: and, according to some late discoveries, it seems to be ascertained that many of the sea¬ 
weed consists of congeries of animalculae. Thus we see that the vegetable and animal kingdoms not only 
closely approximate, but that they do, in fact, exist in the most intimate union. 
