160 – II.3. BRASSICA CROPS (BRASSICA SPP.)
this group (Figure 3.6). It is grown for its thick stemmed flowering shoots that are cut for
market as the first flowers open, allowing for several harvests. The common names for
this variant include Gai Lan and Chinese broccoli. Tsen and Lee (1942) include the
subsp. rosularis and subsp. narinosa in this chinensis group. The USDA Germplasm
Resources Information Network (GRIN) database includes rosularis in the chinensis
group, but keeps narinosa as a separate subspecies (USDA-ARS, 2011). The plants of the
subsp. narinosa are stout, low growing, glabrous biennials. The lower leaves are small,
puckered and orbicular-ovate with broad white petioles, arranged in short clusters.
The upper stem leaves are very broad, entire and clasping. Siliques are about 2 cm long or
less with a very short, stout beak about one-half or one-third as long as the pod. Tsen and
Lee (1942) also place subsp. japonica and subsp. nipposinica within the chinensis group;
however, the USDA keeps both of these subspecies separate (USDA-ARS, 2011). These
two subspecies are considered synonyms for this form, exhibiting pencil-thin leaf stems
supporting deeply indented feathery leaves (Figure 3.7). The flowering stalks produce
siliques about 6 cm long.
Figure 3.4. B. rapa subsp. Chinensis, Bok choy
Source: Courtesy Tainong Seeds.
Figure 3.5. B. rapa subsp. Chinensis, Baby or Shanghai bok choy
Source: Courtesy Tainong Seeds.
Figure 3.6. B. rapa subsp. Parachinensis, Gai Lan or Chinese broccoli
Source: Courtesy Evergreen Seeds.
Figure 3.7. B. rapa subsp. Nipposinica
Source: Courtesy North Carolina State University.
B. rapa subsp. rapa, the common turnip, develops a bulbous storage organ in the first
year of growth. The top 1-6 cm above ground is an expansion of the hypocotyl that is
fused with the expanded root below ground. A narrow tap root extends below the storage
