ORDER HYPOCREALES 289 



Stroma the orange-colored perithecia develop, projecting from the surface 

 by their short ostioles. Cordyceps consists of many species mostly parasitic 

 on insects but with one or two species growing on subterranean fungi. 

 They produce stout or slender stalks bearing a round or more often elon- 

 gated, usually pointed, stromatic head in which arise the numerous 

 perithecia. The latter may be almost completely buried in the stroma or 

 they may project from it so as to be almost free. The well-known "vege- 

 table caterpillar" is a species of this genus. This fungus attacks a cater- 

 pillar which has entered the ground to pupate and from its body a stalk 

 several inches high emerges into the air bearing the perithecia in the 

 stroma in its upper part. Claviceps, the ergot fungus, with a dozen or more 

 species, produces its purple sclerotia in the spikelets of grasses and related 

 plants. On the ground, usually after overwintering, they send out stalked 

 stromatic heads in which the perithecia arise. The ascospores infect the 

 flower heads of the host species where an external conidia-bearing layer is 

 produced (Sphacelia stage) . These conidia are borne by insects or rain to 

 other grasses. Eventually the ovaries are completely filled, or all except a 

 small portion of the upper end, with a firm stromatic mass which may be 

 many times as large as the normal ovary. C. purpurea (Fr.) Tul. is the 

 commonest species of ergot. It occurs in cultivated rye, less often in wheat, 

 and in many other grasses. The fresh sclerotia have considerable medicinal 

 value. They are poisonous when eaten in large quantity as often happens 

 in time of famine when highly ergotized rye or wheat is consumed by the 

 underfed populace. Pastures in which this fungus is abundant sometimes 

 cause serious diseased conditions to develop in the animals feeding there. 

 (Figs. 93, 94.) 



The author has long contended that the color and consistency of the 

 perithecium or stroma are not at all satisfactory as a basis of distinction 

 of the Sphaeriales and Hypocreales. The structure and mode of develop- 

 ment of the perithecium are of far greater value in determining the true 

 relationships. Many of the Hypocreales should be placed in the Sphae- 

 riales and perhaps some in the Pseudosphaeriales. The fact that many, 

 perhaps the majority, of the species of the Hypocreales are described as 

 lacking paraphyses suggests the need of more intensive research upon the 



Fig. 93. Hypocreales. (A-C) Family Nectriaceae. (A, B) Nectria cinnabarina Fr. 

 (A) Portion of tree branch with conidial stromata (Tubercularia stage) with and with- 

 out surrounding perithecia. (B) Section through stroma with two perithecia at one 

 side, the remainder still conidiiferous. (C) Sphaerostilbe gracilipes Tul. Section through 

 stroma showing two perithecia and a synnema and conidial head of the Stilbella stage. 

 (D-G) Family Clavicipitaceae. (D) Cordyceps militaris Link. Caterpillar with several 

 stalked stromata. (E) Cordyceps ophioglossoides Link. Asci containing ascospores. 

 (F, G) Claviceps purpurea (Fr.) Tul. (F) Section of stromatic head. (G) Section through 

 a single perithecium. (A-E, after L. R. and C. T. Tulasne: Selecta fungorum carpo- 

 logia, vol. 3, pp. 1-221. F-G, after Tulasne from Engler and Prantl: Die Naturli- 

 chen Pflanzenfamilien, Leipzig, W. Engelmann.) 



