ENDOPHYTIC PARASITES. 



37^ 



of species of Astragalus (Papilionaceae of Asia Minor), the entire vegetative body- 

 consists indeed of single, jointed cell-filaments, which this investigator terms simply 

 mycelium. He follows this up into the growing-point of the host-plant, and shows 

 how, out of this vegetative body, in the tissue of the leaf-base of the host, cushion- 

 like swellings arise, from which the flower-buds of the parasite develop, and which 

 finally protrude right and left out of the base of the leaf. 



It has been mentioned above that many Fungi complete their vegetative 

 development entirely in the interior of their host-plants (and animals), finally 

 putting forth only their fructifications to the exterior. In this class of plants, 

 so remarkable also in other respects, we meet however with exacdy the opposite 



Fig. 244. — hc^ Tissues of the root of a Cissiis in which the vegetative body bb of a Bntgntaitsia lias 

 penetrated. Transverse section— highly magniiied (after Graf Solms-Laubach). 



extreme, namely, that the host-plant is entirely enclosed within the parasite — that the 

 parasitic Fungus, grows around the Alga which nourishes it on all sides, so that 

 Fungus and Alga together constitute in a certain sense a single mass consisting of 

 two forms of tissue, of colourless fungal tissue and of green algal cells. This is the 

 case in the Lichens. 



If we now cast a short glance at the saprophytes, we find the ordinary case 

 among the Phanerogamic species to be that the plant, after germination, developes 

 within the nourishing substratum (mostly loose humus), while its vegetative body 

 dissolves and absorbs the vegetable remains enveloping it. Only after prolonged 

 nourishment and invigoration of the plant does the saprophyte send up flowering 



B b 2 



