There are two principal traditions of Tai Chi in the Chen Family. In both cases the traditions were a combination of the Tai Chi that was taught to the Chen Family by Chiang Fa with the traditional Chen Family Cannon Pounding (Pao Chui) art which had derived from the Shaolin Temple tradition.
One school of Tai Chi, the so-called Old Frame of Chen Tai Chi developed from Chen Chiang-hsing (who taught Yang Lu-chan) and his student, Chen Gen-yun. His student Chen Yan-xi taught Chen Fa-ke (1887- 1957, the foremost exponent of this style whose students are responsible for its spread.
The New Frame of Chen Tai Chi developed from Chen You-heng, another student of Chiang Fa and developed via Chen Chung-sang to Chen Xin [a.k.a Chen Pin-sang] (1849-1929), the foremost latter- day exponent of this style .
The Old Frame Chen Style of Tai Chi bears a close resemblance to the New Frame Chen Style and also to the Zhao Bao and Hu Lei styles. Apparently it is not based on the classic '13 postures' which are central to the Yang and Wu Styles of Tai Chi and so it varies considerably from them.
For more detailed information on the historical development of these styles of Tai Chi see Peter Lim's fine articles: