A genus containing three hundred or more species from all parts of the world. They are characterized by having linear or oblong sori on the under surfaces or near the margins of the fronds, and the veins are forked or pinnate, free.

Asplenium Nidus australasicum.

Fig. 311. - Asplenium Nidus australasicum.

Only a few kinds are grown largely for market work, amongst the best being: biforme, often mistaken for bnlbiferum, but being more compact in growth; Belangeri, a native of Java, with finely divided fronds; bulbiferum, the well-known "Carrot-top Fern", with graceful arching fronds that produce bulbils or offsets freely, as the name indicates; A. Colensoi, A. foeni-culaceum, A. Hilli, A. inoequale, A, lucidum, and A. erectum are other kinds that sell best in 3-in. pots, and are wanted at all times. A. Nidus, the "Birds' Nest Fern" from Australia, has become a very popular market Fern of late years, and it is not unusual for one firm alone to have an annual output of 60,000 to 70,000 plants in 3-in. pots, besides large numbers in 5-in. and 7-in. pots. The large shining-green fronds forming a cuplike cluster are highly decorative. The variety australasicum (fig. 311), has a black and sharply keeled rachis, while multilobwm or multilacerum has the upper portion of the fronds cut into crested or pinnatifid segments.