Frostweed Family
Crocanthemum
Identification notes: The identification of most of our species of Crocanthemum requires an understanding of the 2 types of flowers produced. Chasmogamous flowers have showy yellow petals and larger sepals, the distinct portion of the 2 linear outer sepals usually linear, (0.7-)1.3-5.5mm long, the distinct portion of the 3 broader inner sepals 2.5-12(-14)mm long. Cleistogamous flowers lack petals and have smaller sepals, the distinct portion of the 2 linear outer sepals 0.2-3mm long, the distinct portion of the 3 broader inner sepals 1.5-4.8mm long. In our species the chasmogamous flowers open earlier (April-July) than the cleistogamous (June-September). In others, the two types of flowers open at the same time (March-June) or cleistogamous flowers are nearly always absent. Capsules from chasmogamous flowers are larger and contain more seeds than those from cleistogamous flowers.1 Chasmogamous flowers usually solitary, terminal or subterminal, later overtopped by lateral branches; seeds papillate, 35-46 per
chasmogamous capsule, 5-9(-12) per cleistogamous capsule; chasmogamous capsules (4-)6-7(-8.5)mm long, cleistogamous capsules
(2-)2.3-3.0(-3.8)mm long; upper surface of cauline leaves with some long simple trichomes mixed with shorter stellate trichomes
.............................................................................................................................................................................. Long-branched Frostweed
1 Chasmogamous flowers usually (1-)2-18, rarely overtopped by lateral branches; seeds smooth or reticulate, 12-35 per chasmogamous
capsule, 1-20 per cleistogamous capsule; chasmogamous capsules (2.4-)3.5-5.7mm long, cleistogamous capsules 1.5-4.2mm long; upper
surface of cauline leaves with the shorter stellate trichomes only.
2 Stems mostly 20-50cm tall, clustered, arising from an upright stem; distinct portion of outer sepals of cleistogamous flowers linear,
(0.3-)0.6-1.2(-1.8)mm long, about 3-5× as long as wide; distinct portion of calyx of chasmogamous flowers (2.4-)3.5-4.5(-8)mm long;
cleistogamous capsules sharply 3-angled in cross-section; leaf with broadly cuneate base ........................................... Hoary Frostweed
2 Stems mostly 10-30cm tall, scattered, arising from horizontal elongate rootstocks; distinct portion of outer sepals of cleistogamous
flowers rudimentary, knob-like, 0.2-0.5mm long, 1-2× as long as wide; distinct portion of calyx of chasmogamous flowers (0.7-)1.5-3.0
(-4.0)mm long; cleistogamous capsules rounded in cross-section; leaf with narrowly cuneate to attenuate base .............Low Frostweed
Lechea
Identification notes: Lechea is recognizable by its production of numerous basal shoots (usually prostrate) in late summer and fall. These are evergreen and overwinter, and the fertile stems (usually erect or ascending) are produced from renewed growth of the basal shoots in the spring and summer.
1 Pubescence of stems strongly spreading, not appressed; inner sepals U- or V-shaped in cross-section); plant tall, often > 50cm tall
..................................................................................................................................................................................................... Hairy Pinweed
1 Pubescence of stems more or less appressed, usually strongly so; inner sepals shallowly curved in cross section; plants variable in height.
2 Outer (slender) sepals equaling or exceeding inner (broad) sepals.
3 Base of fruiting calyx clearly differentiated into a hardened, shiny, yellowish, obconic base 0.4-0.6mm long, contrasting in color and
texture with the rest of the calyx; pedicels averaging > 2mm long .................................................................... Oblong-fruited Pinweed
3 Base of fruiting calyx not conspicuously differentiated in texture and color; pedicels averaging < 1.5(-2)mm long .............................
................................................................................................................................................................................ Thyme-leaved Pinweed
2 Outer (slender) sepals shorter than inner (broad) sepals.
4 Capsules ellipsoid to narrowly pyriform, normally about 2× as long as wide..................................................... Oblong-fruited Pinweed
4 Capsules of a broader shape, ovoid, broadly ellipsoid, or subglobose, normally < 1.5× as long as wide.
5 Capsules obviously longer than the sepals................................................................................................................... Leggett's Pinweed
5 Capsules almost completely enveloped by the sepals.
6 Leaves sparsely pubescent on midrib and margin only beneath; branches and stems sparsely subappressed-pilose; seeds 4-6
....................................................................................................................................................................... Large-podded Pinweed
6 Leaves appressed pubescent on surface beneath; branches and stems moderately to densely gray-canescent; seeds 2-3
....................................................................................................................................................................................... Beach Pinweed