264 



SCIENCE. 



have peculiar organs, such as absorbing glands, glandular 

 hairs, stellate hairs, protecting scales, and a variety of other 

 special appendages. All these have been developed by 

 time and necessity, in remarkable profusion and perfection 

 in the vegetation of Southern Florida. Although the 

 meagre soil produces no nutritious grasses, and scarcely 

 enough of an honest vegetation to keep an herbivorous an- 

 imal from starving ; yet there is an abundant flora such as 

 it is — air plants, parasitic growths, insectivorous plants, 

 and strange herbs seeking a livelihood in any other way 

 than the good old honest one of growing from their roots. 

 It is this fact which makes the microscopial interest of bot- 

 anical researches in Central Florida. One can scarcely 

 examine with a two-thirds objective the flowers, leaves or 

 stems of any plant growing there without discovering some 

 beautiful or striking modification of plant hairs, or scales, 

 or glands, or other absorbing or secreting organs. 



We will notice first the Onosmodium as found in Florida 

 — O. virginianum. It grows from Virginia south, but is 

 more glandular I think, in Florida than anywhere else. It 

 will be almost the first plant one would stop to observe on 

 entering the pine woods — a dark-green, narrow-leaved, bi- 

 ennial herb ; its straight stem of the second year's growth, 

 about a foot high, bearing a raceme-like cluster of flowers, 

 coiled at the end, and straightening out as the flowers ex- 

 pand. The leaves of this plant are thickly studded on both 

 sides with stiff transparent hairs, lying nearly flat on the 

 surface, and all pointing toward the tip end of the leaf. 

 At the base of each hair is a cluster of glandular cells, 

 amounting sometimes to fifty or more, arranged in beauti- 

 ful geometrical forms. When pressed and dried in the her- 

 barium, the body of the leaf turns to a dark green, almost 

 black, and on this back-ground, with a half-inch objective, 

 the hairs stand out like sculptured glass, and the glands 

 like mosaics of purest pearls. I think it is the most at- 

 tractive opaque object that can be shown under the micro- 

 scope. 



That these glandular cells, covering, as the)' do, nearly 

 half the surface of the leaves, especially the upper surface, 

 and differing from all other vegetable cells, subserve an im- 

 portant purpose in the sustenance of the plant, there cannot 

 be any doubt ; but just what that purpose is, or what is the 

 mode of operation, I think, has never been ascertained. 



In the same locality will very likely be found the most 

 beautiful of all the Croton plants, the C. argyranthemum. 

 Unlike the other Crotons, which are bushes, this is an herb 

 growing only about a foot high, with a milky sap which ex- 

 udes when the stem is broken. The leaves are silvery, 

 verging in some cases to a bronze color, and are thickly 

 covered on the upper side with most remarkable and beau- 

 tiful stellate scales. The riowcr-buds and stem, when 

 pressed, make much more beautiful opaque objects than the 

 leaves. 



The object of these scales is, without doubt, to prevent 

 the too rapid evaporation of the moisture stored up in the 

 plant. They are the exquisitely woven blankets which pre- 

 serve the precious juices so laboriously gathered. The 

 same kind of covering is spread over the leaves and stems 

 of all the air-plants ol Florida, and doubtless for the same 

 purpose. The well known Florida moss, although not a 

 moss,, but a member of the pine-apple family {Tillandsia 

 usneoides),\s< an exceedingly beautiful object under the mic- 

 roscope. Each hanging stem is overlaid with filmy white 

 scales, every one ol which is fastened in its place by what 

 would seem to be the stamp of some miniature seal on 

 golden-tinted wax. This plant as ordinarily seen on the 

 live oaks ne.n cities, is a dirty-looking and unatliacli 



oes In the name of "black moss." Hut in out- 

 of-the-way places, removed from the du t and ^moke of Set- 

 tled localities, it is pearly white, and exceedingly beautiful 

 both to the naked eye and undei any power of magnifica- 

 tion. Florida moss should be preserved with only a very 

 slight pressure, just enough to make the threads lie straight. 

 After it has di led in this way, small cuttings may be mount- 

 ed in the ordinary 1 ells lor opaque mounting. 



On the high banks ol the lake, and in the adjoining 

 m ty be found the large-leaved and \ igorous-growing 



Calicarpa (C. Ameticana), times < tiled the French mui' 



berry, a, bush growi ig ime live or six feel in height. The 

 under side of the leaves ot tins plant are nearly co\ 



with little round, yellow, sessile glands, flattened on top 

 and marked off into eight ten sections by ribs like those on 

 a melon. They are in immense numbers — something like 

 thirty thousand to the square inch — over half a million on a 

 good-sized leaf. Under a light net-work of branching 

 glandular hairs, viewed with a two-thirds objective, these 

 polished ambor-colored disks glisten like a spangle of 

 golden beads. The same kind of glands is found on the 

 leaves of many other shrubs in Florida — the sweet myrtle 

 (Jlfyrica ceriferd), the low-ground blueberry ( Vaccinium te- 

 nellum) a certain bush or dwarf hickory (Carya glabra) and 

 some others. These glands have been variously called 

 resin dots, resin glands and odoriferous glands. So far as 

 I can judge, however, they are not connected with any res- 

 inous or odoriferous secretions. From their almost perfect 

 resemblance to the terminal bulb of the mushroon glands 

 of the Pinguicula and Drosera, which are known to be ab- 

 sorbing glands, the probability is that these also serve to 

 absorb moisture and ammonia from the atmosphere and 

 from rains. Although I am free to acknowledge that the 

 position of the glands, being for the most part on the un- 

 der side of the leaves, militates somewhat against this view 

 of their purpose. 



Great care will have to be taken in pressing and drying 

 vegetable specimens in the moist climate of Florida. The 

 little threads of the mould fungus will be sure to creep over 

 the surface of the leaves, spoiling them for microscopical 

 material, if they are not quickly and effectually dried. For 

 this purpose it is well to have a good supply of the bibulous 

 botanical paper, and to change the specimens every day to 

 fresh sheets for at least four or five days. The sheets, after 

 being once used, should be spread out in the sun to dry. A 

 weight of about thirty pounds may be used for the pres- 

 sure. 



The objects heretofore mentioned are all for opaque 

 mounting. Almost every preparer of slides has his own 

 favorite method for this kind of work. I myself prefer the 

 use of the transparent shellac cells. Clarified shellac is 

 dissolved in alcohol, and filtered through cotton-wool un- 

 der a bell-glass, and with the application of heat. The solu- 

 tion is evaporated down until it is so thick that it will only 

 just run — almost a jelly. In this cond ; tion it can be put 

 on a slide with a camel's hair brush on the turn-table, and 

 very quickly worked up into a ring with the point of a 

 knife, used first on the inside to make the cell of the size 

 wanted, and then on the outside to turn the cement up into 

 a compact ring. Two or three applications of the cement, 

 with intervals of a day or two after each, will make 

 cells of sufficient depth for all ordinary specimens. 

 These cells dry quite slowly; and if artificial heat is 

 used it must be increased only very gradually, other- 

 wise vapor of alcohol bubbles will make their appearance 

 in them. A small ring of Brunswick black may be made 

 in the inside of the cell, to which, when thoroughly dry, 

 the object may be fastened with a very little liquid 

 marine glue. In this case both sides of the leaf can be 

 seen, which is often desirable. In all opaque mountings a 

 minute aperture should in some way be left open into the 

 inside of the cell, so that it shall not be hermetically sealed 

 up. This little precaution will save an innumerable num- 

 ber of failures. 



The collector in Florida will not fail to secure a supply 

 of the-leaf stems of the castor oil plant (Ricinus communis). 

 In regions beyond the influence of frosts, this plant grows 

 continuously from year to year, and becomes quite a tree. 

 It is only in such a growth that the spiral tissue of the 

 fibro-vasculai bundles is fully perfected. The castor oil 

 plants grown in our climate during one short season, will 

 furnish very little spiral tissue, mostly spotted ducts and 

 scalariform cells. There is no more beautiful object for 

 multiple staining than thin longitudinal sections through 

 the woody liber, the vasculai tissues, and. the pith cells of 

 well matured leaf-stems of the castor oil plant. I will 

 briefly describe my process Ol making these stablings. 

 After being decolorized in chlorinated soda, the sections 

 may be left lor half a day or more in a solution of carmine 

 in water containing a lewdiops ol aipia ammonia: ; then for 

 half an hour in a laihei weak solution ol extract of logwood 

 in alum water, and finally 10 to 15 minutes in a weak solu- 

 tion of anilin violet or blue in alcohol. From this they can 



