This section is from the book "The Native Flowers And Ferns Of The United States ", by Thomas Meehan. Also available from Amazon: The Native Flowers and Ferns of the United States in Their Botanical, Horticultural, And Popular Aspects.
Leaves entire, round heart-shaped, one to two inches broad, thickish; petioles filiform; lobes of the white corolla broadly oval, naked, except the crest-like, yellowish gland at their base, twice the length of the lanceolate calyx-lobes ; style none ; seeds smooth and even. (Gray's Manual of the Botany of the Northern United States. See also Chapman's Flora of the Southern UnitedStates, and Wood's Class-Booh of Botany.)
THE plant which forms our present theme affords us an excellent lesson in regard to the meaning of botanical names. When we hear for the first time the name of a human individual, we do not concern ourselves about its meaning in any relation to the person bearing it. We like to know its history, for its own sake. That some Mr. Baker or Mr. Taylor had a primeval ancestor who followed baking or clothes-making may, perhaps, have been the reason why he and all his posterity bear that name; but we do not expect the persons so named now to follow these occupations. A name which means nothing is just as good as one with the most expressive of meanings. Now, many persons think names which are expressive should be given to plants; but expressive names so often mislead that those which have no meaning of any immediate application to the plant in question are generally preferable. For this reason those which commemorate the services of botanists are much in favor with many who describe new plants. How names capable of special application may mislead, is shown in the present instance. Limnanthemum is derived from two Greek words, limne, mud, and anthos, a flower, because, as one would suppose, the original species grew in a marshy or muddy place. But the earliest known species, L. nympfuzoides, a European plant, grows under water, where the leaves can float on the surface, and does not seem to occur in situations strictly conforming to those alluded to. It is properly an aquatic, and not a marsh plant, as the name would imply, and as Gmelin (author of the "Flora of Siberia") seems to have supposed. Our species was named L. laainosiim, from the Latin lacns, a lake, by Grisebach, the author of a Flora of the West Indies, from its actual place of growth, and it might be supposed as a corrective of its generic name. But there are in other countries more species that grow in lakes, so we see there is nothing distinctive in either name; and those therefore who might infer it to be so, would be led into serious error.
In old works our plant has to be sought for under the name of Mcnyanthcs, or, as it is spelled by Pliny, Minianthes. Some writers contend that this name is derived from mens, a month, in allusion to its old reputation in certain diseases, or, as Dr. Gray says, from the fact that the flowers last about a month, while those who adopt the Plinian orthography maintain that it comes from the miniate or red-lead color of the flowers. At a later period, it will be found among Villarsia, so named from a French botanist, Villar or Villars. Nuttall has it under Villarsia, and Michaux and Muhlenberg under 'Mcnyanthcs; but all our modern botanists are united on Limnauthamim. It differs from Mcnyanthcs particularly in the shape of the corolla, which, when expanded, is wheel-shaped, as seen in our Fig. 4, while that of Mcnyanthcs is formed like a funnel.
The flowers proceeding from the petiole or leaf-stalk will, of course, attract attention, and their position will afford a good lesson in vegetable morphology, as showing the intimate relationship between leaves and the axis. It will be remembered by the student that a flower does not consist simply of modified leaves, but of the modified stem and leaves, - a whole branch, and not merely the leaves of a branch. Now, it is a well-known axiom that the lesser cannot be greater than its whole. It follows, therefore, that if the flower, which is essentially stem and leaves, spring from a leaf-stalk, the leaf-stalk must itself possess the same essential elements. Other plants will afford the same lesson in other ways, and we take this one now, simply because the occasion presents itself. Besides the position and nature of the flowers, it will also be interesting to note that roots and buds, making new growths, start out in close neighborhood to the clusters of flowers, so that the petiole or leaf-stalk becomes essentially a stolon, as in the runner of a strawberry, differing from the latter in nothing but its erect position. It is altogether a very good lesson as to how one part of a plant grows out of, or is formed from, another or other parts.
The flowers themselves are very interesting. There are five small sepals, as seen in Fig. 5, and, alternating with them, five petals very prettily fringed and slightly incurved at the edges. (Figs. 4, 3, 6.) Alternate with these, and opposite the sepals, are five stamens, and alternate again with these are five glands. (Fig. 4.) These glands are possibly only another series of stamens, which, by becoming absorbed by the petals in a very early stage, have been aborted. The flowers open and close at regular times of the day, but under exactly what conditions the writer has not been able to determine. The roots remain in the mud during the winter, pushing up in early spring, and by the end of June the flowers appear from underneath the leaf-blades, only a portion of these leaves, however, producing flowers. There appears no difference i.n strength or vigor between those leaves which flower and those which do not, although there must certainly be a difference in nutrition in favor of the flowering leaves. This, also, is a fact well worthy of remark and further investigation, as in most other plants such a difference in nutrition would manifest itself in a diminished, or increased growth.
It is said by some who have grown certain species of this genus that they are very easy of cultivation, taking care of themselves without any difficulty when once established. This one, however, does not seem to have been taken in charge by gardeners, but would no doubt do as well as any of the rest. For small lakes or ponds it would be very appropriate. The way to plant these, and water plants generally, is to tie them up loosely in thin muslin, with earth and stones, and then sink the whole bundle in the water.
There have been no poetical associations connected with the Floating Heart, as there have been with so many other representatives of the gentianaceous order. It seems strange that it has been overlooked. Emblematists might surely have discovered in the dart-like, faded flowers, partly seen from the heart-shaped leaves, some relation to the story of Cupid, and this the more so from its very suggestive common name of Floating Heart.
It is remarkable that there should be but very few species in the genus to which our plant belongs, and yet that there should be representatives of it in every quarter of the globe. Its headquarters seems to be in the East Indies, where there may be half a dozen species. There are, also, one or two in New Holland, about the same number at the Cape of Good Hope, and two in our own country. One is found in Japan, another in Europe and Eastern Asia, one in Brazil and one in South America, with possibly a few others here and there.
Our Floating Heart seems to be abundant in Maine and New England, becoming rare as it reaches New Jersey, although it extends to Florida on this side of the Alleghanies. Its western limit in the north seems to be Ohio, but it travels southwest and is found in abundance in Missouri and Arkansas.
The specimen from which the accompanying drawing was made was kindly furnished to us by Mr. Jackson Dawson, the head gardener of the Arnold Arboretum, Boston, Mass.
1. Barren leaves.
2. Fertile leaf.
3. Closed flowers, showing fringed edged petals enlarged.
4. Enlarged expanded flower.
5. Flowers, natural size, showing calyx.
6. Flowers, natural size, showing incurved petals.