EXPLANATION OF PLATE VIH. 



Fig. 1. VALLiiXEHiA Spiralis. A dioecious aquatic p'ant of Europe, A'-ncnea, and 

 Nev/ Holland. Leaves radical, riband-like. A, sianunaie flower. Peduncles short, 

 terminaled by a spike ; ovate, spathaceous, reuiainni.^; under water until tne period Ibi 

 fertilizing the pistillate tlowcrs. B, tertile plant, peduncles very long, spiral, uni- 

 rtowei-ed. Flower spathaceous, floating. 'I'hia sini;ular 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 ol the pistillate flower? untwist 

 themselves, and the flowers rise to the surface of the water ; the short spike of stara- 

 inate flowers breaJvs oil" 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 s'.rutiolcs. The Duekweed tribe. A floating, stoloniferous plant. 

 Leaves radical, spreading, flabelliform. 



Fig. 3. Trapa nutans * {Onagrcc.) An aquatic plant. Stem sub-merged, pro- 

 ducing radical tilamenis of two sons; the one simple, fllifonn ; the other ramifled 

 and pinnate; they appear to be transformed leaves. The leaves are terminal, diverg- 

 ing ; ^jetioles broad, dentate. A, a plant soon after germination ; a, the fruit; 6, peti- 

 ole from one of tlie two cotyledons which remam enclosed in the fruit; c, the othei 

 cotyledon; d, root j e. stem. B, a plant more developed. 



Fig. 4. BvTOMVH nmhellat us: A Flowering-rush tribe. A plant which grows on the 

 border of lakes and rivers. Leaves radical, erect, riband-like, pointed at the summit. 

 Scape rectilinear. Umbel simple, terminal, involucred. 



Fig. 5. PorxKocKToy rompressiun t An annual, aquatic plant, common in brooks 

 and ditches. Stem compressed, slender, leafy. Leaves alternate, linear. .Spikes ter- 

 minal, interrupted. Flower whorled. 



Fig. <). Nklumbo nnr.ifern.§ An aquatic, perennial plant found in Egypt, India, 

 and America- Leaves radical, peduncled, peltate, round, concave. Peduncle one- 

 flow^ered. Calyx caducous. Corolla of many spreading i)etals. .Stamens numerous ; 

 style, very .short ; stigma, like a cup; n, young leaves ; b, flower : c, fruit. 



FiiT. 7. Ju.vi;cs comalnmpratus.W The Rush tribe. {JunccB.) ."^tem very simple, 

 aphyllous, rectilinear, vertical, terminating in a point. Panicle crowded, unilateral. 



Fig. 8. Yvcxjsartirulntns.'^ The .Sea-weed tribe. {AlgcE.) A marine plant of the 

 Atlantic Ocean. Frond cartilaginous, dichotomou^^, moniliforin, articulated, each joint 

 containing fruit. 



Fig. 9. Fucus digitatus. Stem simple, cyiiudric. Frond compressed, digitate, 

 flabelliform. 



Fig. 10. Fucus nutans. A maiine plant which, detaching itself from the rockf< 

 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. U. Fucus obtusatus. A marine plant of Cape Van- 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 nooiiitiers of the natural method, to be nearly allied to Oiuigrae, distinguished Iroiu it only by soli- 

 tary, pendulous ovules. 



t Tliis is the leading genus in the order Butomeac, of Lindley ; by.De Candolle and IMirbel, placed in Alis- 

 maceee, to which it is closely allied. 



I Of the order Na;des of Jussicu, or Fluviales of more modern botanists. " In this order," Lindley re- 

 marks, " we have the nearest approach, exci.pt in Pistiacea;, to the division of flowi riess plants. The peri- 

 anth is reduced to a tew imperfect scales, the habit is almost that of Conileras, and there is in some ol the 

 genera, either a total absence of spiral vessels, or that tbrm of tissue e.vists in a very rudimentary state." 

 Tli« atfiriityof this order to Aroidcce is manifest from the tendency of some siKJCies to produce a rudimentary 

 8I*th.i. Mirbel place.s this m the order Aiismacuffi. 



i In the order Nelumbone^ of De Candolle ;— by most writers united to Nympliaiacese, with which it dil 

 jr«|*9 in the structure ot ilie fruit, but si^rees in the foliage and tiowers. The fruit of one species of Nelumbium 

 U thougl)t to be the Egyptian bean ol ancient writers. 



B " This plant," according to Lindley, " stands between Petaloideous and Glumaceous Monocotyledons, 

 agreeing with the to.-mer in the tioral leaves, having assum d the Verticillate state necessary to constitute a 

 porianth, and with the latter in tlieir texture. From Falms, indepcndtaitly of their habit, they are distiu- 

 guished by the constant tendency to (iroduce more than one ovule in each cell, and by the embryo never bo- 

 ing remote from the hilum. Juncus is an instance of a mon()cotyledonous plant having a distinct pith ' 



IT Lindley describes the order Algae as " aquatic, leaiiess, floweriess plants." He says, " Whatever m- 

 genuity may be employed in determining the relative degree of dignity in the vegetable creation betweetn 

 Fungi, Lichen.s. and AlgiP, it seems to me that the conclusion constantly arrived at is, that Algic are only 

 to be distinguished from the other two by tlieir being in water, and that hut for the influence which that mo 

 dium e.verciscs on them, they would be identical with Lichens on the one hand, and Fungi on the other. 

 Those who have ever examined the surfaces of stones constantly moistened by water, 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 oi 

 gardens after rains, cannot fail to have remarked a green, mucous slime, with which they are covered. Thia 

 elime consists of Alga; in their simplest state of organization, belonging to the genera Palmella, Nostoc, &c. 

 Tlw 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 w.hich penetrate or develop 

 themselves ni 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 kingdoina not oiiij 

 tioswly approximate, but tliat they do, in fact, exist in the most intimate union. 



