For the most useful commercial adi-antums see the article on Ferns, in which all the most important commercial ferns are treated collectively. The following adiantum notes are by Mr. W. H. Taplin:
A. Legraxdi. The maidenhair family includes a wonderful variety in both size and form, and a collection embracing all the distinct forms grown into specimens would occupy a very large house.
A. Legrandi belongs to the dwarf section, the stipes or stems being usually but a few inches in length and the fronds very compact and closely clothed with small pinna?. In fact the growth in small plants is so close and overlapping that the foliage is quite subject to damping off unless the house in which it is grown is kept well ventilated.
Regarding the origin of this fern but little is known, and it seems probable that it is a seedling variation from Adiantum Pecottii, which it very much resembles, the chief distinction apparently being found in the longer leaf stems of A. Legrandi, while both varieties present the same dark green color of the foliage. As a trade fern A. Legrandi has not become prominent, and as a matter of fact it is less frequently seen in trade collections now than it was a few years ago, the demand in this line being confined to ferns that are more sturdy and less brittle.
The culture of A. Legrandi presents no special difficulty, apart from the liability to damping that has already been alluded to, and by keeping the water off the foliage and giving free ventilation, the trouble from this cause may be reduced greatly.
In getting up specimens of these small growing adiantums for exhibition purposes, it is a good plan to group several young plants in a pan about ten inches in diameter, and a shapely plant may thus be formed in a few months by treating them in the same manner as one would A. cuneatum for a similar purpose.
A. Macrophyllum. This is one of the most distinct of the large family of maidenhair ferns, and as a matter of fact to many persons to whom the idea of a maidenhair fern is associated with the light and airy fronds of A. cuneatum, the rather stiff and heavy looking leaves of this species would seem to belong to an entirely different genus.
The large pinnated species of adiantum, among which we find A. macro-phyllum, A. Peruvianum, A. Seemannii and A. Wilsonii, form a very interesting group, and one which adds greatly to the beauty and variety of a collection of ferns. Adiantum macrophyllum is a moderate growing species, the fronds being erect, from one to two feet high, simple pinnate, and having stiff black stems.
The pinnae of the barren fronds are very large, being frequently three to four inches long, by about two inches wide, and when first unfolding are bright pink in color, finally changing to deep green.
The pinnae of the fertile fronds are usually smaller, the spores being found in an almost continuous band around the margin. These spores germinate fairly well if carefully gathered and preserved, and the young plants thus secured are much better than those obtained from division of old crowns, as they grow more freely and in better form.
No special difficulty is experienced in the culture of A. macrophyllum, the main features being a moderately light soil, good drainage, and the glass shaded throughout the greater portion of the year. In regard to temperature, the same may be given as to A. Farleyense, namely, from 65 to 70 degrees at night, and also like the latter variety it may be said that A. macrophyllum does not like a strong draught over the young foliage while unfolding, else it is likely to be crippled, though after the fronds of this species are fully hardened they will stand quite a good deal of exposure without any danger of injury.
A. macrophyllum is a native of the West Indies and tropical America, and has been in cultivation for a little more than a century, though yet uncommon in trade collections.
A. Mundulum. This is one of the many interesting and useful forms of Adiantum cuneatum, and is correctly termed Adiantum cuneatum mundu-lum. The varietal name, which signifies neat, is well applied in this case, the plant being of dwarf and compact habit, and is better adapted for small ferneries than as an exhibition plant.
The fronds of A. cuneatum mundulum are shorter and rather stiffer than those of the parent form, not often more than nine or ten inches long, very dark green, and closely furnished with narrow, wedge-shaped pinnae. In general outline the fronds are deltoid, and when well matured they possess sufficient substance to be useful in cut flower work, where a small frond is required.
A. cuneatum mundulum comes true from spores, and also germinates freely, the spores being produced abundantly on old plants, and it flourishes under the same treatment as A. cuneatum, thus being by no means difficult to manage.
Nicely grown plants in 3-inch pots are very short and bushy, and may be used to advantage where A. cuneatum proves too tall, and if the plants are not soft when used, will possibly last a little longer than the last named fern, under the same conditions.
A. cuneatum mundulum is of garden origin, and although in cultivation since 1879, is not frequently met with in the trade, in fact, seems scarcer now than it was ten years ago, no doubt owing to the greater demand for ferns of more endurance than is found among the maidenhairs in general.
A. Tetraphyllum. Among the less common species of maidenhair ferns, Adiantum tetraphyllum is deserving of special mention, and some idea of its general outline may be had from the illustration which accompanies this note. But, unfortunately, an ordinary photograph fails to show us the fine distinctions of coloring that present themselves in the living plant, and in consequence we are compelled to fall back upon cold type for our descriptions.