baby stars, linanthus, and leptosiphons

genus Leptosiphon

Member of phlox family (family Polemoniaceae)
dicots (class Magnoliopsida)
flowering plants (subphylum Angiospermae)

Except for historical records that I'm ignoring, there are no other wild species of this genus in the bay area.

There are quite a few Leptosiphon species in the bay area and my IDs thus far have not been good quality. This page lists some key features, but I don’t attempt to replicate the whole Jepson decision tree. Instead, each flower description includes enough information to (hopefully) confirm an ID hypothesis (with help from CalPhoto).

Key features:

densely bracted head or not
calyx position (among bracts or just under corolla)
calyx & calyx membrane [may be difficult to isolate, so not used in key, but useful for Jepson comparison]
corolla tube, throat, and lobe colors
exact corolla lobe length
leaf lobe length and shape
stigmas linear or not (Leptosiphons generally have 3 stigmas on 1 style and 5 stamens)

corolla pediceled above sparse bracts

I.e. the calyx is at the top of the pedicel and ± cupping the corolla throat.

serpentine leptosiphon
Leptosiphon ambiguus

calyx clearly shorter than corolla tube & throat
corolla:

throat maroon
lobes pink with a yellow base, possibly white between
lobes 4–6 mm

common

flax-flowered linanthus
Leptosiphon liniflorus

calyx slightly shorter than corolla tube & throat
corolla:

throat yellow
lobes white, usually with distinct colored veins
lobes 8–10 mm

uncommon

photo

pygmy linanthus
Leptosiphon pygmaeus

calyx slightly longer than corolla tube & throat, so calyx lobes tend to poke between petals
corolla:

throat yellow
lobes pale purple/white
lobes 1–2 mm

rare

photo

bolander’s linanthus
Leptosiphon bolanderi

calyx slightly shorter than corolla tube & throat
corolla:

throat generally yellow
lobes pink/pale purple/white
lobes 2–3 mm

rare

large-flowered leptosiphon
Leptosiphon grandiflorus

corolla ± sessile above densely bracted head (corolla starts spreading within bracts or not much above)
corolla 15–30 mm long

throat yellow
lobes white blending to pink/pale purple/white

uncommon

corolla salverform above densely bracted heads

I.e. the calyx is among the bracts, but the corolla has a long tube.

corolla lobes > 4 mm

photo

coast yellow leptosiphon
Leptosiphon croceus

corolla:

tube yellow/reddish
throat yellow-orange
lobes bright yellow, generally with 2 red spots at base
lobes 6–8 mm

leaf lobes 4–7 mm, middle lobe rounded
very rare

photo

rose leptosiphon
Leptosiphon rosaceus

corolla:

tube pink/yellow
throat yellow
lobes white, blending to pale purple for a rare subspecies
lobes generally 6–9 mm, tip rounded

leaf lobes 5–12 mm, narrow to linear, rounded
calyx ± glabrous, nonglandular
rare

false babystars
Leptosiphon androsaceus

corolla:

tube reddish
throat generally violet at the base and yellow above, but may be white
lobes pink/pale purple/white
lobes generally > 8 mm, often abruptly soft-pointed
stigmas 2–6 mm and well exserted from corolla tube

leaf lobes 6–30 mm, tips pointed
calyx ciliate, nonglandular, abaxially generally glabrous
common
different petal shape (see photos) and slightly larger corolla diameter than variable linanthus (Leptosiphon parviflorus)

variable linanthus
Leptosiphon parviflorus

corolla:

tube maroon/pink/yellow
throat yellow/orange/purple
lobes pink/yellow/purple/white, sometimes with red/purple spots at the base [Jepson says “often”, CalPhotos says “almost never”]
lobes 4–8 mm
stigmas 1–7 mm and strongly exserted from corolla tube

leaf lobes 2–18 mm, middle lobe tip acute
calyx densely hairy, glandular
common
different petal shape (see photos) and slightly smaller corolla diameter than false babystars (Leptosiphon androsaceus)