The Different Forms of Flowers on Plants of the Same Species

-styled form utterly ste

of the pistils in the

d species

singular difference in s

German long-

shown to be a distinct s

ly self-

num fa

er heterost

iac

fertility of the

sto

ence in the pollen-grains

styled form alone; develo

in the several Rubiaceous

com

4. Linum g

ong-sty

hort-sty

stig

3.4). The difference is confined to the pistil; in the short-styled form the styles and the stigmas are only about half the length of those in the long- styled. A more important distinction is, that the five stigmas in the short- styled form diverge greatly from one another, and pass out between the filaments of the stamens, and thus lie within the tube of the corolla. In the long-styled form the elongated stigmas stand nearly upright, and alternate with the anthers. In this latter form the length of the stigmas varies considerably, their upper extremities projecting even a little above the anthers, or reaching up only to about their middle. Nevertheless, there is never the slightest diff

long-styled flowers were already thickly covered with their own pollen-so thickly that I could not find one bare stigma, and it was late in the season, namely, September 15th. Altogether, it seemed almost childish to expect any result. Nevertheless from my experiments on Primula, I had faith, and did not hesitate to make the trial, but certainly did not anticipate the full result which was obtained. The germens of t

ot stand very close to any long-styled plants, yet they yielded together nineteen capsules. These facts seem to show that the short-styled plants are more fertile with their own pollen than are the long-styled, and we shall immediately see that this probably is the case. But I suspect that the difference in fertility between the two forms was in this instance in part due to a distinct cause. I repeatedly watched the flowers, and only once saw a humble-bee momentarily alight on one, and then fly away. If bees had visited the several plants, there cannot be a doubt that the four long-styled plants, which did not produce a single capsule, would have borne an abundance. But severa

an average 8.6 seeds per capsule, but only 5.6 appeared to be good. It may be well to state that ten seeds is the maximum production for a capsule, and that our climate cannot be very favourable to this North-African plant. On three occasions the stigmas of nearly a hundred flowers were fertilised illegitimately with their own-form pollen, taken from separate plants, so as to prevent any possible ill effects from close inter-breeding. Many other flowers were also produced, which, as before stated, must have received plenty of their own pollen; yet from all these flowers, borne by the seventeen

ived their own pollen. From all these flowers on the seventeen short-styled plants only fifteen capsules were produced, of which only eleven contained any good seed, on an average 4.2 per capsule. As remarked in the case of the long- styled plants, some even of these capsules were perhaps the product of a little pollen accidentally fallen from the adjoining flowers of the other form on to the stigmas, or transported by Thrips. Nevertheless the short-styled plants seem t

tely fertilised in an accidental manner, the relative fertility of the two legitimate and two illegitimate unions cannot be compared with cer

onfirms my suspicion that some of the few capsules produced by the foregoing seventeen short-styled plants were the product of accidental legitimate fertilisation. Other

m pollen led me to examine into its apparent cause; and the results are so curious that they are worth giv

RS

I repeated this experiment on another flower, and in eighteen hours the stigmas were penetrated by a multitude of long pollen- tubes. This is what might have been expected, as the union is a legitimate one. The converse experiment was likewise tried, and pollen fr

OND

ingle pollen-grain had emitted a tube, and this was a very short one. To make sure that the pollen was good, I took in this case, and in most of the other cases, pollen e

IR

ll five stigmas of a long-styled flower; after nineteen h

RTH

, with the same result

FT

stigmas. After an interval of three days, the stigmas were examined, and, instead of being discoloured and twisted, they were straight

xperiments are

XT

ter twenty-two hours these two stigmas were discoloured, slightly twisted, and penetrated by the tubes of numerous pollen-grains: the other

ENT

in the same manner,

HTH

ith pollen from a short-styled flower were penetrated by innumerable tubes, which were as yet short, and the stigmas themselves

NT

four hours the one stigma was somewhat discoloured and twisted, and penetrated by many long tubes: the other four stigmas were q

NT

with their tubes to a very short depth. The one stigma, which was deeply penetrated by a multitude of tubes from the short-styled pollen, presented

ue ultimately to a great depth; and that after twenty-four hours the stigmas thus penetrated change colour, become twisted, and appear half-withered. On the other hand, pollen-grains from a long-styled flower placed on its own stigmas, do not emit their tubes

pollen and the two stigmas are widely dissimilar in their mutual reaction-the stigmas of each form being almost powerless on their own pollen, but causing, through some mysterious influence, apparently by simple contact (for I could detect no viscid secretion), the pollen-grains of the opposite form to protrude their tubes. It may be said that the two pollens and the two stigmas mutually recognise each

m pe

the mature pistils twist round, so as to face the circumference of the flower; but to this point I shall presently return. Differently from what occurs in L. grandiflorum, the long-styled flowers have stamens hardly more than half the length of those in the short-styled. The size of the pollen-grains is rather variable; after some doubt, I have come to the conclusion that there is no uniform difference between the grains in t

re illegitimately fertilised with their own-form pollen, taken in every case from a separate plant; and not one set a seed- capsule: twelve other flowers were legitimately fertilised with pollen from short-styled flowers; and they set nine capsules, each including on an average 7 good seeds, ten being the maximum number ever produced. Of the flowers on the short-styled plants, twelve were illegitimately fertilised wi

hese three capsules were the product of accidental legitimate fertilisation, owing to the branches of the plants of the two forms interlocking, I will not pretend to dec

capsules were very fine, and as five were borne on one twig, I suspect that some minute insect had accidentally got under the net and had brought pollen from the other form

more fertile with their own pollen than are the long-styled plants. Anyhow we have the clearest evidence, that the stigmas of each form

ir own pollen, and about 30 with pollen from another plant belonging to the same form, and these 50 flowers did not set a single capsule. On the other

eir tubes, though this action did not lead to the production of seeds. After an interval of eighteen hours, the tubes penetrated the stigmatic tissue, but to what depth I did not ascertai

efer to the wind or to insects as if the alternative were indifferent. This view, according to my experience, is entirely erroneous. When the wind is the agent in carrying pollen, either from one sex to the other, or from hermaphrodite to hermaphrodite, we can recognise structure as manifestly adapted to its action as to that of insects when these are the carriers. We see adaptation to the wind in the incoherence of the pollen,-in the inordinate quantity produced (as in the Coniferae, Spinage, etc.),-in the dangling anthers well fitted to shake out the pollen,-in the absence or small size of the perianth,-in the protrusion of the stigmas at the period of fertilisation,-in the flowers being produced before they are hidden by the leaves,-and in the stigmas being downy or plumos

g-styled flowers of L. perenne whilst in bud. But by the time the flowers have expanded, the five stigmas twist round so as to face the circumference, owing to the torsion of that part of the style which lies beneath the stigma. I should state that the five stigmas do not always turn round completely, two or three sometimes facing only obliquely outwards. My observations were made during October; a

other. Insects are attracted by five drops of nectar, secreted exteriorly at the base of the stamens, so that to reach these drops they must insert their proboscides outside the ring of broad filaments, between them and the petals. In the short-styled form of the above three species, the stigmas face the axis of the flower; and had the styles retained their original upright and central position, not only would the stigmas have presented their backs to the insects

of either form (for the stamens in this species occupy the same position in both forms), they will get their foreheads or proboscides well dusted with the coherent pollen. As soon as they visit the flowers of the long-styled form they will necessarily leave pollen on the proper surface o

removed on the near side. (3/3. I neglected to get drawings made from fresh flowers of the two forms. But Mr. Fitch has made the above sketch of a

pistils; and this is what is required for the legitimate fertilisation of both forms. The corolla of L. perenne is more expanded than that of L. grandiflorum, and the stigmas of the long-styled form do not diverge greatly from one another; nor do the stamens of either form. Hence insects, especially rather small ones, will not insert their proboscides between the stigmas of the long-styled form, nor between the anthers of either form (Figure 3.5), but will strike against

f the styles in the long- styled flowers alone, as

gular course of events. (3/4. 'Fertilisation of Orchids' page 108; 2nd edition 1877 page 84.) The belief that the flowers of many plants are fertilised in the bud, that is, are perpetually self-fertilised, is a most effectual bar to understanding their real structure. I am, however, far from wishing to assert that some flowers, during certain seasons, are not fertilised in the bud; for I have reason to believe that this is the case. A good observer, resting his belief on the usual kin

m fl

quired, but have never heard of its seeding in this country. Certainly my own plants never produced a single seed as long as I possessed only one of the two forms. After considerable search I procured both forms, but from want of time only a few experiments were made. Two plants of the two forms were planted some way apart in my garden, and were not covered by nets. Three flowers on the long- styled plant were legitimately fertilised with pollen from the short-styled plant, and one of them set a fine capsule. No other capsules were produced by this plant. Three flowers on the short-styled plant were legitimately fertilised with pollen from the long-styled, and all three produced capsules,

pecial study of the genus, says that about half of the sixty-five species known to him are heterostyled. (3/7. 'Botanische Zeitung' September 18, 1863 page 281.) This is the case with L. trigynum, which differs so much from the other species that it has been formed by him into a distinct genus. (3/8. It is not improbable that the allied genus, Hugonia, is heterostyl

flowers are so constructed that they can freely fertilise themselves; but if visited by insects they might be cross- fertilised. He has, however, only once seen the flowers thus visited during the day; but it may be suspected that they are frequented during the night by small moths for the sake of the five minute drops of nectar secreted. Lastly, L. Lewisii is said by Planchon to bear on the same plant flowers with

IA (BORA

ria off

in length, and as 7 to 6 in breadth. They do not differ in the appearance of their contents. The corolla of the one form differs in shape from that of the other in nearly the same manner as in Primula; but besides this difference the flowers of the short-styled are generally the larger of the two. Hildebrand collected on the Siebengebirge, ten wild long-styled and ten short-styled plants. The former bore 289 flowers, of which 186 (i.e. 64 per cent) had set fruit, y

naria officinalis

Nature of

ber of Flower

mber of Frui

age Number of

short-styled. Legitimat

by pollen of other plant of same fo

f long-styled. Legitimat

y pollen of other plant of same for

ong-styled plants collected on the Siebengebirge by Hildebrand, and which, no doubt, had been legitimately fertilised. In the following year one of my plants was covered by a net, and even under these unfavourable conditions it produced spontaneously a few seeds. It should be observed that as the flowers stand either almost horizontally or hang considerably downwards, pollen from the short stamens would be likely to fall on the stigma. We thus see that the English long-styled plants when illegitimately fertilised were highly fertile, whilst the German plants similarly treated by Hildebrand were completely sterile. How to account for this wide discordance in our results I know not. Hildebrand cultivated his plants in pots and kept them for a time in the house, whilst mine were grown out of doors; and he thinks that this difference of treatment may have caused the difference in our results

ia angus

Pulmonaria

ong-sty

hort-sty

lve short-styled flowers of P. angustifolia were legitimately fertilised with pollen from long-styled plants of P. officinalis (which, as we have just seen, are moderately self-fertile), but they did not produce a single fruit. Thirty-six long-styled flowers of P. angustifolia were also illegitimately fertilised during two seasons with pollen from the long-styled P. officinalis, but all these flowers dropped off unimpregnated. Had the plants been mere varieties of the same species these illegitimate crosse

Pulmonaria a

Nature of

ber of Flower

mber of Frui

age Number of

short-styled. Legitimat

rm pollen. Illegitima

f long-styled. Legitimat

rm pollen. Illegitimat

form the distance between these organs in the long-styled is to the same distance in the short-styled form as 100 to 69; so that the stigma in the one form does not stand on a level with the anthers in the other. The long-styled pistil is sometimes thrice as long as that of the short-styled; but from an average of ten measurements of both, its length to that of the short-styled was as 100 to 56. The stigma varies in being more or less, though slightly, lobed. The anthers also vary much in length in both forms, but in a greater degree in the long-styled than in the short-styled-form; many in the former being from 80 to 63, and in the latter from 80 to 70 divisions of the micrometer in length. From an average of seven measurements, the short-styled anthers were to those from the long-styled as 100 to 91 in length. Lastly, the pollen-grains from the long-styled flowers varied between 13 and 11.5 divisions of the micrometer, and those from the short-styl

emed to my son to produce a greater number of flowers than the long-styled; and he came to this conclusion before a similar statement had been published by Hildebrand with respect to P. officinalis. My son gathered ten branches from ten different plants of both forms, and found the number of

f 100 to 35. The 18 long-styled flowers illegitimately fertilised yielded no seeds,-not even a vestige of one. Two long-styled plants which were placed under a net produced 138 flowers, besides those which were artificially fertilised, and none of these set any fruit; nor did some plants of the same form which were protected during the next summer. Two other long-styled plants were left uncovered (all the short-styled plants having been previously covered up), and humble-bees, which had their foreheads white with pollen, incess

to the degree of self-fertility of the short-styled plants. A plant belonging to this form and covered by a net bore 28 flowers besides those which had been artificially fertilised, and of all these only two produced a fruit each including a single seed. This high degree of self-sterility no doubt depended merely on the stigmas not receiving any pollen, or not a sufficient quantity. For after carefully covering all the long-styled plants in my garden, several short-styled plants were left exposed to the visits of humble-bees, and their stigmas will thus have received plenty of short-styled pollen; a

deteriorated condition of their pollen; nevertheless this pollen was highly efficient when applied to the stigmas of the short-styled flowers. With several species of Primula the short- styled flowers are much more sterile than the long-styled, when both are illegitimately fertilised; and it is a tempting view, as formerly remarked, that this greater sterility of the short-styled flowers is a special adaptation to check self-fertilisation, as their stigmas are eminently liable to receive their own pollen. This view

ing to Hildebrand, is not

ilung bei den Pflan

st-formed flowers are apt to have stamens somewhat arrested in development, with very little pollen in their anthers; and in such flowers the stigma projects above the anthers, whilst generally it stands below and sometimes on a level with them. I could detect no difference in the size of the pollen-grain or in the structure of the stigma in the plants which differed most in the above respects; and all of them, when protected from the access of insects, yiel

agopyrum (P

gonum fagopyrum.

-styled form; lower fi

rs have dehisced,

above the eight short stamens, and stand on a level with the anthers of the eight long stamens in the short-styled form; and so it is conversely with the stigmas and stamens of this latter form. I could perceive n

ers were dragged several times over two heads of flowers on long-styled plants, protected under a net, w

e manner from other long-styled plants, and were thus illegitimatel

ike manner from long-styled flowers, and were thus legitimat

from other short- styled plants, and were thus illegitimatel

average 7.50 seeds per head; whereas the seven illegitimately fertilised heads yielded less than half the number, or on an average only 3.28 seeds. The legitimately crossed seeds f

produce so many seeds as some neighbouring uncovered plants which were visited by insects. Therefore the flowers of neither form when left to fertilise themselves late in the season without the aid of insects, are nearly so sterile as most other heterostyled plants. A large number of insects, namely 41 kinds as observed by H. Muller, visit the flowers fo

shows that P. bistorta is so strongly proterandrous (the anthers generally falling off before the stigmas are mature) that the flowers must be cross-fertilised by the many insects which visit them. Other species bear much less conspicuous flowers which secrete little or

Burnettiana

her form: it differs remarkably from the stigma of the long-styled form, in being more papillose, and in being longer in the ratio of 100 to 60. The anthers of the upper stamens in the short-styled form are supported on free filaments, and project above the throat of the corolla, whilst the anthers of the lower stamens are seated in the throat on a level with the upper stamens of the other form. The diameters of a considerable number of grains from both sets of anthers in both forms were measured, but they did not differ in any trustworthy degree. The mean diameter of twenty-two grains from the short-styled flower was to that of twenty-four grains from the long-styled, as 100 to 99. The anthers of the upper stamens in the short-styled form appeared to be poorly developed, and contained a considerable number of shrivelled grains which were omitted in striking the above average. N

trifoliata

in size. The stamens of the short-styled are almost double the length of those of the long-styled; so that their anthers stand rather above the level of the stigma of the long-styled form. The anthers also vary much in size, but seem often to be of larger size in the short-styled flowers. My son made with the camera many drawings of the pollen-grains, and those from the short-styled

m Indicum (

at of the short-styled, and is very much thinner in the ratio of about 3 to 5. The foliaceous stigma is more expanded, and twice as large as that of the short-styled form. In the latter the stamens are about twice as long as those of the long-styled, and t

[sp.?] (Ge

ther on a level with the tips of the sepals or considerably beneath them. The foliaceous stigma in the long-styled form is larger, with the expansions running farther down the style, than in the other form. One of the most remarkable differences between the two forms is that the anthers of the longer stamens in the short- styled flowers are conspicuously longer than those of the shorter stamens in the long-styled flowers. In the former the sub-triangu

itute a well-marked sub-tribe of the Gentianeae. All the species, as far as at

suspensa (

t Kew. The first proved to be long-styled, and the other two short-styled. In the long-styled form, the pistil is in length to that of the short-styled as 100 to 38, the lobes of the stigma being a little longer (as 10 to 9), but narrower and less divergent. This last character, however, may be only a temporary one. There seems to be no difference in the papillose condition of the two stigmas. In the short-styled form, the stamens are in length to those of the long-styled as 100 to 66

ears likewise to be heter

the long-styled form alo

ished figures of this spe

ed f

p.?] (Cor

tion in the highest degree, and yet the two forms may have stamens of equal length, and pollen-grains of equal size. In the present species of Cordia, the stamens of both forms are of nearly equal length, those of the short-styled being rather the longest; and the anthers of both are seated i

they are considerably shorter than those of the long-styled form. This

ulchella vel aggreg

hat the pistil goes on growing for some time after the anthers have dehisced. Nevertheless it is possible to class the flowers under two forms. In some of the long-styled, the length of pistil to that of the short-styled was as 100 to 82; but this result was gained by reducing the size of the corollas to the same scale. In another pair of flowers the difference in length between the pistils of the two forms was certainly greater, but they were not actually measured. In the short-styled flowers whether large or small, the stigma is seated low down within the tube of the corolla. The papillae on the long-styled stigma are longer than those on the short-styled, in the ratio of 100 to 40. The filaments in some of the short-styled flowers were, to those of the long-styled, as 100 to 25 in length, the free, or unattached portion being alone measu

tosiphon)

led, in the ratio of 100 to 42. My son measured nine pollen-grains from the long-styled, and the same number from the short-styled form; and the mean diameter of the former was to that of the latter as 100 to 81. Considering this difference, as well as that between the stigmas of the two forms, there can be no doubt that this species is heter

lata (Pole

greatly in position. The stigma is more papillose, and of greater length (in one instance in the ratio of 100 to 67), in the short-styled flowers than in the long-styled. My son measured twenty pollen-grains from a short-styled flower, and nine from a long- styled, and the former were in diameter to the latter as 100 to 93; and this difference accords with the belief that the plant is heterostyled. But the grains from the short-styled varied much in diameter. He afterwards measured ten grains from a distinct long-styled flower, and ten from another plant of the same form, and these grains differed in diameter in the ratio of 100 to 90. The mean diameter of these two lots of twenty grains was to that of twelve grains from another short-styled flower as 100 to 75: here, then, the grains from the short-styled form were considerably smaller than those from the long-styled, which is the reverse of what occurred in the former instance, and of what is the general rule with heterostyled plants. The whole case is perplexing in the highest degree, and will not be understood until experiments are tried on living plants. The greater length, and more papillose condition of the stigma in the short-styled than in the long-styled flowers, looks as if the plant was heterostyled; for we know that wi

[sp.?] (Ery

8. Erythro

ong-sty

hort-sty

Fritz Muller, mag

rs of the short-styled flowers stand on a level with the stigmas of the other form; but the stamens are longer by only one-fourth or one- fifth of their own length than those of the long-styled. Consequently the anthers of the latter do not stand on a level with, but rather above the stigmas of the other form. Differently from what occurs in the following closely allied genus, Sethia, the stamens are of nearly equal length in the flowers of the same form. The pollen-grains of the s

inata (Eryt

d form. The stigmas of the long-styled seem rather smaller than those of the short-styled. All the stamens in the short-styled flowers are of nearly equal length, whereas in long-styled they differ in length, being alternately a little longer and shorter; and this difference in the stamens of the two forms is probably related, as we shall hereafter see in the case of the short-sty

formosum (H

lobular stigmas about twice as thick. These stand just above the numerous anthers and a little beneath the tips of the petals. In the short-styled form the anthers project high above the pistils, the stigmas of which diverge between the three bundles of stamens, and stand only a little above the tips of the sepals. The stamens in this form are

elata (Ver

two forms do not differ much in length, nor as far as I could perceive in their papillae. In the long-styled flowers the filaments adhere to the corolla close up to the anthers, which are enclosed some way down within the tube. In the short-styled flowers the filaments are free above the point where the anthers are seated in the other form, and they project from the corolla to an equal height with that of the s

ila ob

those in the short-styled form, strictly as 44 to 100; and what is much more important, they were in a rudimentary condition in the two flowers examined by me, and did not contain a single grain of pollen. In the short-styled form, the divided stigma, which as we have seen is much shortened, is thicker and more fleshy than the stigma of the long-styled, and is covered with small irregular projections, formed of rather large cells. It had the appearance of having suffered from hyperthrophy, and is probably incapable of fertilisation. If this be so the plant is dioecious, and judging from the two species previously described, it probably was once heterostyled, and has since been rendered dioecious by the pistil in the one form, and the st

IAC

much larger number of heterostyled ge

ella

Gray 'Manual of the Botany of the United States' 1856 page 172.) In my first series of experiments (1864) I did not suppose that this curious arrangement of the flowers would have any influence on their fertility; and in several instances only one of the two flowers in a pair was fertilised; and a large proportion or all of these failed to produce

down the tube. In the short- styled flowers those organs occupy reversed positions. In this latter form the fresh pollen-grains

1. Mitche

Nature of

s of Flowers fertilised

Drupes produced duri

of good Seeds per Drupe i

Seas

f short-styled. Legitim

rm pollen. Illegitima

of long-styled. Legitim

rm pollen. Illegitimat

e unions together

ate unions togeth

ne of 8 seeds. Of the illegitimately fertilised paired flowers only 18 per cent yielded berries, six of which contained on an average only 2.1 seeds, with a maximum in one of 4 seeds. Thus the two legitimate

seeds. The plants thus treated were therefore excessively sterile, and their slight degree of fertility may be attributed in part to the action of the many individuals of Thrips which haunted the flowers. Mr. J. Scott informs

p. near valerian

ce in the length of the pistils in the two forms, it is remarkable that the pollen-grains differ very little in size, and Fritz Muller was struck with the same fact. In a dry state the grains from the short-styled flowers could just be perceived to be larger than those from the long-styled, and when both were swollen by immersion in water, the former were to the latter in diameter in the ratio of 100 to 92. In the long-styled flowers beaded hairs almost fill up the mouth of the corolla and project above it; they therefore stand above the anthers and beneath the stigma. In the short-styled flowers a similar brush of hairs is si

ed many dozen fruits, each containing two good seeds. I fertilised in the same manner three heads on the same long- styled plant with pollen from another long-styled plant, so that these were fertilised illegitimately, and they did not yield a single seed. Nor did th

sp.?] (Ru

.9. Faram

ort-styl

ong-styl

ried specimens. Pollen-gra

z Mu

short-styled form are a little larger than those of the long-styled; and their pollen-grains are to those of the other form as 100 to 67 in diameter. But the pollen-grains of the two forms differ in a much more remarkable manner, of which no other instance is known; those from the short-styled flowers being covered with sharp points; the smaller ones from the long-styled being quite smooth. Fritz Muller remarks that this difference between the pollen-grains of the two forms is evidently of service to the plant; for the grains from the projecting stamens of the short-styled form, if smoo

n their axes, but dehisce on their inner sides, as is the common rule with the Rubiaceae; and this is the best position for the adherence of the pollen-grains to the proboscis of an entering insect. Fritz Muller therefore infers that as the plant became heterostyled, and as the stamens of the short- styled form increased in length, they gradually acquired the highly beneficial power of rotating on their own axes. But he has further shown, by the careful examination of many flowers, that this power has not as yet been perfected; and, consequently, that a certain proportion of the pollen is rendered useless, namely, that from the anthers which do not rotate properly. It thus appears that the development of the plant

ffered in a uniform manner in the length of their stamens and pistils,-in the form of their stigmas,-in the manner of dehiscence and slightly in the size of their anthers,-and t

amed in the herbarium

form the anthers are placed in the mouth of the corolla above the stigma, which occupies the same position as the anthers in the other form, being seated only a short way down the tube. Therefore the pistil of the long-styled form does not exceed in length that of the short-

coerulea (

been observed. The stigmas of the long-styled form are shorter, stouter, and far more hispid than in the other form. The stigmatic hairs or papillae on the former are .04 millimetres, and on the lat

a state of nature yielded an average of 21.5 seeds per capsule. Some short-styled plants, which had been planted by themselves in the Botanic Gardens, where it was not likely that they would have been visited by insects that had previously visited long-styled plants, produce

a [sp.?] (

than the corresponding organs in the short-styled flowers. In the latter the anthers are longer, and the divergent stigmas decidedly longer and apparently thinner than in the long-styled form. Owing to the state of the specimens, I could not decide whether t

[sp.?] (R

s stand rather beneath the level of the anthers in the other or long- styled form, these being enclosed within the tube of the corolla. The pistil of the long-styled form is nearly thrice as long as that of the short-styled, or, speaking strictly, as 100 to 39; and the papillae on the stigma of the former are broader, in

um [sp.?] (

osed stigma of the latter also stands a little above the level of the enclosed anthers in the long-styled form. The pistil of the long-styled is about twice as long as that of the short-styled, with its two stigmas consider

[sp.?] (

orm it stands on a level with the anthers of the other form. So that the want of strict correspondence in height between the stigmas and anthers in the two forms is reversed, compared with what occurs in Hedyotis. The long-styled pistil is to that of the short-styled as 100

icrantha (

cupy the same position as the stigma of the other form, and they are considerably longer than those of the long-styled form. As the summit of the stigma in the short-styled form stands beneath the bases of the anthers, which are seated halfway down the corolla, the style has been extremely shortened in this form, its length to that of the long- styled being, in the specimens examined, only as 5.3 to 100! The stigma, also, in the short-styled form is very much shorter than that in the long-styled, in the

tilised with their own pollen several flowers on a plant of this latter species in my hothouse, but they did not set a single fruit. From Wight and Arnott's description, there seems to be little doubt that Knoxia in India is heterostyled; and Asa Gra

erves notice that the genera now known to be heterostyled are not grouped in one or two of these tribes, but are distributed in no less than eight of them. From this fact we may infer that most of the genera have acquired their heterostyled structure independently of one another; that is, they have not inherited this structure from some one or even two or three progen