1466 



A TEXTBOOK OF THEORETICAL BOTANY 



Asterad Type. The basal cell contributes to the building of the 

 embryo. 



II. In the second cell-generation the terminal cell divides transversely. 



a. The basal cell contributes little or nothing to the building of 



the embryo. 



CaryophyUad Type. The basal cell becomes a large suspensor 



cell usually without division. 



Solanad Type. The basal cell forms a suspensor of two or 



more cells. 



b. Chenopodiad Type. The basal cell contributes to the building 

 of the embryo. 



The Piperad Type is based on Peperomia (Fig. 1343) rather than on Piper, 

 about which little is known embryologically. The Type includes Balano- 

 phora and Scabiosa. 



Fig. 1343. — Peperomia pellucida. Development of the embryo. A, Four- 

 celled embryo surrounded by a few endosperm cells. B-E, Stages in 

 embryo and endosperm development. (A after Campbell, the rest 

 after Johnson.) 



The Onagrad Type is fairly widespread and is more or less uniform in 

 the Onagraceae. In this Type are also included: Euphorbia, Capsella 

 (Fig. 1344), Lythrum, Mentha, Veronica, Trifolium, Liliiim, and Junciis, as 

 well as a number of other genera, each distinguished by some Variation. 



The Asterad Type includes almost all the members of the Compositae 

 which have been examined and the following well-known genera, as Varia- 

 tions: Erodium, Polygonum, Urtica, Lamium, Oxalis and Poa (Fig. 1345). 



