[1] It grows below 1,200 metres (3,900 ft) in chaparral, coastal prairie, coastal sage scrub, closed-cone pine forest, grassland, and oak woodland habitats.

[1] It is California Department of Fish and Wildlife and IUCN listed Vulnerable species, and is on the California Native Plant Society Inventory of Rare and Endangered Plants.

[2] Its current range is uncertain because many known occurrences of the plant have been extirpated.

[2] Leptosiphon grandiflorus is an annual herb producing a hairy stem with occasional leaves which are each divided into linear lobes up to 3 centimeters (1.2 in) long.

The inflorescence at the tip of the stem is a loose cluster of a few white or pinkish funnel-shaped flowers with lobes up to 1.5 centimeters (0.59 in) long.