Torrubia
(named by Leveille, in honour of a Spanish writer on "Vegetable Wasps," as wasps attacked by the plants of this genus [see below] were formerly called). A genus of Fungi, of which by far the larger number are parasitic in insects, spiders, and their allies; while a small number live on other Fungi. Torrubia is the name by which the genus is generally known; but it must give place to the name Cordyceps, previously conferred by the eminent Swedish mycologist, Elias Fries.
The genus belongs to the group of compound Pyrenomycetes (which see); but is peculiar in the substances on which the various species live, and also in the erect, clubbed, fleshy mass of mycelium (called a stroma), the appearance of which is shown.On, or embedded in, it are the flask-shaped perithecia, inclosing asci. In each of the latter are eight thread-like spores, which usually soon break into joints. These joints are capable of giving origin to the cycle again, if they fall on a suitable stratum, e.g., the body of an insect. But they produce not the Pyrenomycetous fungus, but a smaller vertical stroma, branched or simple, composed of a bundle of mycelium threads, which bear numerous round or elliptical, pale, minute conidia, or spores. This stage of these Fungi was formerly regarded as belonging to a distinct group (Hyphomycetes), without asci, and the various forms were grouped together under a new generic name--Isaria. This genus resembles Cordyceps in having an erect, club-shaped stroma; but, instead of inclosing perithecia with asci, the filaments of the mycelium end in free tips, each of which bears small, oval or globular, pale conidia, capable of reproducing either Isaria or Cordyceps. For convenience, the genus Isaria is still kept up, as the perfect or mature forms of a large number of the Fungi placed in it have not yet been recognised, and to attempt to dispense with the group would, at present, only cause confusion and uncertainty. Moreover, there is reason to believe that several of the forms referred to Isaria do not belong to Cordyceps, but should be referred to other genera; in-a-much as they live on a wider range of materials, and some injure living plants also (e.g., Isaria fuciformis destroys grasses in Australia and in the South of England), while Cordyceps is not known as a parasite on living plants. Most of the species in the latter genus abound in tropical countries; but several have been found in Britain, in all their stages of development, on dead insects. Among the best-known of these are C. entomorrhiza and C. militaris: these form slender stalks 1in. to 2in in height, the clubbed heads on which are ovoid or globose. On tracing the stalks downwards, they are found to rise from the bodies of larvae or pupae, buried in the soil or among dead leaves. These Fungi may be regarded as beneficial to gardeners, inasmuch as they destroy insects, many of which feed on garden produce. They are not often met with, however, and can scarcely be regarded as of much importance from this point of view. On the other hand, no species of Cordyceps is known to be injurious in gardens. Probably, the species most widely known, by its popular name at least, is the so-called "Vegetable Caterpillar," often sent from New Zealand. This reaches a height of from 6in. to 8in., the club being from 3in. to 4in. long, and 1/8in. thick. It grows out of the body of some large larva (usually that of an insect allied to the Otter Moth or Ghost Swift), and is often erroneously supposed by the finders to be a caterpillar in course of development into a Fungus. This Fungus is C. Hugelii, Corda; though more generally referred to in English works by the name C. Robertsii, given to it, by the Rev. M. J. Berkeley, at a later date than Corda's. Mr. Berkeley has described a still larger species from Australia, under the name Sphaeria Taylori.