Flora of New Zealand Series

Sisymbrium heterophyllum Forst. f. Prodr. 1786, 46.

C. hirsuta L. var. debilis Banks ex Hook. f. Handbk N.Z. Fl. 1864, 12.

C. heterophylla (Forst. f.) Schulz in Engl. Bot. Jb. 32, 1903, 487 (non Wood in Bot. & Fl. 1870, 38).

A polymorphic sp. not fully resolvable into distinct vars without breeding and cultural tests, owing to the interplay of genetic and habitat factors. It is closely related to C. hirsuta L., which is naturalized and possibly hybridizes with it. The two vars described below show clear-cut differences. A third, more complex, group is also described. Names are not given in view of the uncertainty as to the type.

(a) Erect var. Delicate herb up to 30 cm. or more tall, sparingly branched from rather stout to slender stock. Radical lvs ∞, up to c. 10 cm. long, with 5 to 15 alt. to opp. pinnae on slender petiolules. Pinnae obovate-cuneate, broad-oblong to suborbicular, crenate-mucronate, shallowly lobed to entire; terminal lflt up to 1 × 1·5 cm., cordate to truncate or cuneate at base. Cauline lvs smaller; pinnae fewer, often narrower, more deeply lobed; lobes crenate-serrate, us. mucronate. Branches erect or spreading, produced into racemes with up to 15 fls or more. Fls distantly placed, pedicels subpatent to ascending, c. 1-2 mm. long. Sepals c. 2-3 mm. long, ± obovate-oblong; petals white, c. 4-5 mm. long, obovate, narrowed into short claw. Ovary glab.; siliques ascending, c. 3 × 1·5 cm.; style slender, c. 1-3 mm. long. Seeds slightly > 1 mm. long. Dist.: N., S., St., Ch. Lowland forest, scrub and streamsides, common. Example of var.: BD 76096, Wainui-o-mata, near Wellington, light forest, Allan.

Schulz's proles macrantha (Mon. Gatt. Cardamine, Engl. Bot. Jb. 32,· 1903, 487) is based on luxuriant forms. His var. macrostylis (loc. cit.) has an attenuate style 1·5 to 2.5 mm. long.

(b) Slender var. Stock very slender, branches ± prone, often rooting at nodes, almost filiform; basal lvs small, soon falling; cauline up to 5 cm. long on filiform petioles; pinnae 3-7, small; terminal pinnae 5-7 mm. long, rather deeply to shallowly lobed (lobes us. 3), lateral entire to 3-lobed. Fls rather smaller. Siliques up to 2.5 cm. long, slender; style c. 2 mm. long. Seeds ± 1 mm. long. Dist.: N., S. Streamsides, damp grassy ground in light shade, less common. Example of var.: BD 65060, A. P. Druce; stream bank on bases of Carex secta, Reporoa Bog, N.W. Ruahines, c. 1200 m.

Schulz's proles micrantha appears to include this var. along with other forms.

A third group has plants with a rather stout stock, much branched above, and-a more compact habit. Branches many, rather dense, c. 5 cm. long; basal lvs us. ∞, c. 4-8 cm. long; lflts 5 to 9 or more, broad-ovate to suborbicular, entire to very shallowly lobed, veins not or obscurely mucronate; cauline lvs few, smaller, more deeply lobed. Racemes terminal, ∞ to few, c. 2-5 cm. long. Siliques c. 2.5 cm. long, erect, rather crowded on subpatent to ascending slender pedicels. Style c. 1 mm. long. The plants are glab. to ± pilose, the habit becoming less dense in shade. Schulz's var. hirtella (loc. cit.) appears to come into this group; described as having the stem below or up to the calyx with spreading short hairs, the lvs also sts hirsute. The development of hairs appears to depend very largely on habitat conditions. Schulz also describes a var. leiocarpa with completely glab. ovary. Plants coming into this group are widely distributed in N. and S. on streamside gravel, in light forest and on rocky ground, in lowland to montane areas. As with most of the accepted spp. the range of forms is very great and the limits uncertain.